The Influence of Green Building Application on High-Rise Building Life Cycle Cost and Valuation in Indonesia

Abstract

The building sector has slowly but constantly had the largest contribution to global carbon emissions. Thus, business in the building sector has a responsibility to contribute to reducing carbon emissions. One of the ways of doing this has been by developing the concept of a green building, which is one of the solutions for sustainable development. However, the main obstacle for the property developer is a misconception that capital cost spending is more important than the life cycle cost of the building. The majority of property owners and developers are more concerned about the initial cost without taking into consideration that the initial cost is closely related to the operational cost of buildings, especially high-rise buildings. From this phenomenon, there are research opportunities that aim to determine how the concept of green influences the financial decisions of developers in Indonesia that are applied to high-rise buildings. The method used in this research is inferential analysis to determine how the influence of the application of green building factors into the valuation of a building. The valuation is based on one of three methods in a building’s valuation, which is the cost approach. Then, a comparison between the building’s valuation using green and non-green is conducted in terms of the cost analysis and sensitivity. The result of the analysis is known that according to the developer practitioners in Indonesia with the green building concept, the increase in construction costs is not always accompanied by a decrease in operating and maintenance costs, as well as an increase in property values. These findings can have implications for achieving expectations, that is increasing property values through the use of the green building concept by reducing the operational and maintenance costs.

1. Introduction

Today’s growing urban population has a long-term impact on the environment and natural resources. Buildings account for 32% of total global energy use [1,2]. The construction industry slowly but progressively contributes the most to carbon emissions in nature, aggravating global warming, which has recently intensified. Buildings account for 50% of the overall energy expenditure in Indonesia and more than 70% of the total power use. The building also accounts for 30% of greenhouse gas emissions and consumes 30% of all generated raw materials. Global energy consumption, particularly in high-story structures, is expected to rise by 70% between 2000 and 2030, and by an even greater percentage beyond these years. The concept of green buildings or environmentally friendly buildings helps to slow the rate of global warming by modifying the microclimate [3].

The processes required to generate an artificial indoor climate through heating, cooling, ventilation, and lighting account for approximately 50% of energy use in buildings. Building energy usage accounts for around 25% of the overall building operating expenditures. In the United Kingdom, buildings consume around 50% of the total commercial energy available domestically. Meanwhile, in China, buildings account for 38% of the total energy consumption. In 2005, heating, ventilation, and air conditioning accounted for 45% of end-user energy consumption in the building sector, followed by water heating (19%), equipment (14%), and lighting (10%). In general, buildings and construction account for at least 30% of global greenhouse gas emissions [4]. Energy has a direct influence on property business because energy costs account for approximately 30% of building operating expenditures. In this case, the building system’s impact should be considered as a whole system for sustainability. The world has to cut greenhouse gas emissions as a prevention against the effects of global warming. The building and property sectors can play a key role in this decrease [5]. For building design, it is critical to consider the long-term environmental and economic benefits of urban expansion and development. It is estimated that environmentally friendly designs employing building technology can lower the emissions of CO₂ by up to 58.3% and save at least 30% of energy [6].

Various strategies were carried out in implementing green building practices, as research by Mahmoud [7] tested living roofs technology in terms of the energy saving in buildings in Saudi Arabia. As a country with a hot and arid climate, the use of living roofs is the right component to be applied to the design of buildings in Saudi Arabia, which mostly use decked roofs. The benefit of using living roofs is that apart from reducing carbon emissions, it can also increase the value of a property. In Barcelona, the research of Moghaddam et al. [8] also investigated the factors that can save energy through building orientation using green facades. Research shows that the building orientation with the support of the use of green facades can significantly reduce energy consumption and increase the thermal comfort of occupants. Lu et al. [9] highlighted the use of Building Integrated Photovoltaics (BIPVs) in Singapore that are climate tropical to achieve zero-energy buildings. The use of BIPVs is believed to provide economic benefits and reduce CO₂ emissions. Lastly, a recent study conducted by Cannavale et al. [10] tested the use of photo-chromic materials in building envelopes which are believed to reduce energy consumption and provide visual comfort for building occupants. Based on this, their research shows that compared to the use of clear glass, photochromic glass is proven to save energy for cooling within one year, and artificial lighting for visual comfort is also the best choice.

Green buildings are designed for economic and environmental sustainability, taking into account the local climate and cultural needs, which can facilitate the occupants’ health, safety, and productivity [5]. The green building movement is now mature enough to demonstrate the value of the green economy in the real estate market for building owners and tenants, as evidenced by the rapid increase in the use of renewable energy and the conversion of information technology and technology development into the development of smart cities, eco-districts, and eco-campuses. Residential high-rise buildings in Indonesia continue to grow, despite the pandemic. This is a unique phenomenon because the property market is declining. It seems that investors are looking at the timeframe to gauge the risks to construction costs and the market’s recovery after the pandemic. In other words, the pandemic period is used as a construction period with an estimated recovery of Indonesia’s very large residential property market. High capital has been invested in high-rise construction. The development of green buildings or green property, especially high-rise buildings, is not only in great demand but has also become a necessity today. In Indonesia, which has a tropical climate, the construction system still relies on the conventional methods; this is because the construction of green buildings still depends on the initiative of investors or building owners. In fact, the use of energy for buildings in the operational phase is very large, which is around 85% of the total CO₂ emissions [11]. One strategy that can reduce the use of energy is to design a building envelope with a natural lighting system through ventilation [12].

The biggest impediment for building developers is the belief that capital expenditures are more essential than building life cycle costs. The bulk of building owners and developers are preoccupied with the initial expenses, failing to comprehend that the initial expenditures are inextricably linked to the building operational costs. The employment of infeasible designers, construction materials, and mechanical/electrical equipment will have an impact on the building’s operational and maintenance expenses over time. According to Razali et al. [13], several misunderstandings in the investment process cause investors to delay investing in this field, which becomes an impediment to investing in the field of sustainable property, such as (1) believing that investment in this field is irrelevant or even detrimental to the risk of financial returns, even though there is no academic evidence to support It, (2) the credibility to back up sustainable investment studies, and (3) the belief that the sustainability factor must contribute value over time. The operational energy consumed for building functions over time is the highest share of energy used in buildings because of the energy needed to provide comfort and various services in buildings that have a long lifetime.

Theoretical descriptions and studies conducted by Li et al. [14] prove that the initial investment, operational costs, and the benefits obtained are the main considerations in green buildings. Many studies have been conducted to determine the impact of the green building idea on the costs [15,16,17,18] and benefits of investing [19,20,21]. One of the reasons for this study is that today’s judgments regarding whether or not to engage in green buildings are typically based simply on upfront expenditures plus, in some cases, decreased energy and water bills [11]. Additionally, because the computation of life cycle costs has not been done, it is unknown exactly how the components of green architecture affect an investment, particularly in Indonesia. Knowing more, particularly about the impact of the use of features in the concept of green construction in high-rise buildings on an investment, will clarify the developer’s stance and gaps in the investment decision.

This research further investigates the aspects of the green building concept that influence developer investment decisions by looking at their application to buildings, which, in this study, takes the form of high-rise buildings in Indonesia. The purpose of this research is to learn more about the impact of using the green building concept on the financial decisions in high-rise buildings. It is hoped that the research findings will provide empirical evidence on the effect of applying the green building concept on a high-rise building investment in Indonesia, as well as become a supporter of the green building concept in terms of investment, encouraging property developers to develop environmentally friendly properties.

Based on the foregoing, it is possible that an investment in a property product is heavily impacted by the benefits which are to be acquired. In terms of the investment costs and returns, the development of green buildings remains a big problem for many Indonesian developers. The use of green building principles is more discretionary in Indonesia and has not become mandatory. No mandatory measures or incentives have been offered to encourage the development of green buildings, such as in Jakarta, which is home to the most stringent building developments. As shown in Figure 1, there are four basic elements related to green building financing, namely, cost reduction because green buildings are more energy efficient compared to conventional buildings [22], initial costs are quite high, especially for new structures [23], increase building performance [24], and property value [25]. The problem formulation in this paper (Figure 1) is “how does the application of elements in the green building concept affect in the finance of high-rise buildings in terms of life cycle cost and valuation?”, and what are the differences between green and non-green buildings based on the scope of the problem formulation?

2. Green Building Variables to Project Finance

The definition of green buildings often has similarities with sustainable buildings, and indeed the two are related. In general, a green building is defined as a high-performance building whose main focus is on the parameters of low energy consumption, water use, emission reduction, reducing the environmental impact, and achieving indoor environmental comfort [12]. In short, green buildings are properties that are designed and built in a resource efficient manner, to reduce the environmental impact and improve human health [15]. While sustainable buildings are intended as buildings designed and built to reduce the adverse effects of human activities, based on three main pillars, namely the economic aspects, social aspects, and environmental aspects [12].

The design and material criteria that will be researched and used as variables can be measured by the investment aspects, which are the design and material aspects. The design aspects are highly considered in designing green buildings. A green building cannot be considered as a sustainable building unless it follows the process from the planning to the design, construction, operation, maintenance, repair, and demolition of the building [26]. This practice extends and complements classical building designs in the interests of the economy, utility, durability, and comfort. Future developments can be demonstrated by a green building design. According to Li et al. [27], sustainable development is essential, hence a green building design is critical. To create a green building that not only has a low environmental impact but is also practical, economical, and comfortable to use, it is critical to integrate the design with a design team that works as a whole throughout the process and considers every aspect of the building in an integrative and holistic manner.

The material aspect Is also heavily studied; it is claimed that employing green building materials can help redirect the indoor air quality (IAQ), meet customer preferences, and meet certain regulatory criteria [28]. The following is a discussion of how the concept of the green building criteria forms the variables in this study. The first produces 4 variables, the second produces 5 variables, and the third produces 3 variables, so a total of 12 variables were studied.

2.1. Appropriate Site Development

The suitability of the site development, that is the consideration of the consequences of the site’s selection, is critical for minimizing the negative environmental impacts that may accompany a project, ranging from the construction activities to the people who will occupy the facility. How will the building’s location be able to reduce the negative effects on the surrounding environment? Land suitability is defined as the ability to maintain/improve urban green areas, avoid new land clearing/greenfield areas, be easily accessible and adjacent to public infrastructure, improve the quality of the microclimate, and lessen the load of rainwater runoff. According to Huo et al. [29], site selection focuses on the reuse and restoration of existing structures or sites, lowering the development footprint, construction waste/garbage, and the city’s heating effect (heat island effect).

The placement of the building must also comply with the legislation, land use, and function, as well as pay attention to the development to avoid negative environmental impacts [30]. Regarding the initial location planning, Hu et al. [31] stated that by minimizing the building footprint (footprint development), such as designing a building to rise upwards so that it has a smaller building footprint than a building design that expands to the side, gives rise to a larger building footprint [32].

Table 1. Formulation of variables related to the suitability of land development.

Source	Land Development Suitability Theory	Regarding Design & Material Aspects	Variables
[29]	Designing the building to rise upwards so that it has a smaller building footprint.	Minimize building footprint	(X1) Thin building design vertically (X2) Horizontal thin building design (X3) Direction of the opening area for natural lighting (X4) Use of green roof
[30]	The location of the building is in accordance with regulations, land use and function, avoiding negative environmental impacts.	Designing buildings
[31]	Designing while minimizing the building footprint.	Minimize building footprint
[32]	Use and restoration of existing buildings or sites; reduce the development footprint; reduce construction waste/garbage and reduce the heat island effect.	Reduce the development footprint and reduce the heat island effect

shows the variable formulation.

The initial variable concept found is the design of the building shape and orientation design as well as the use of green roofs, which will be explained as follows:

2.1.1. Building Shape and Orientation Design

The form of a structure (its stacking, mass, and general geometry) has a substantial impact on its function, energy efficiency, and occupant performance. Many aspects of green design are affected by building orientation, from the building performance to visual stimulation for the building’s inhabitants. Consider the sun’s direction, wind, natural light availability, shade caused by vegetation, topography, and the surrounding structures. High-rise structures receive direct sunshine and heat radiation [33].

The position of the building or buildings with respect to the direction of the sun’s path in the sky is referred to as the good sun orientation. Daylighting can be enhanced by decreasing the depth of the floor slabs, particularly in office buildings. The deeper the floor slabs, the more difficult it is to bring sunlight into the space, increasing the need for artificial lighting. It will be challenging to generate appropriate illumination for the room if the floor slab is longer than 27.5 m. Landscape selection and irrigation water use can also be influenced by the orientation. Aside from having the qualities of a high-rise building, there are several types of buildings that can support high-rise buildings.

High-rise buildings can take the following horizontal forms:

• Triangle and square;
• Round, ellipse, and trapezium;
• Pentagon, hexagon, octagon, and polygon;
• The combination of the above forms.

Vertically, high-rise buildings can take the following forms:

• Increasingly to over, the size is large;
• the higher the building, the smaller the shape;
• The stable period.

The design of the building’s shape can be divided into two types based on the previous definition of tall buildings vertically in a horizontal form [34]: the design of the shape of the building with the formation of a thin vertical building shape and the design of the shape building with the formation of a thin horizontal building shape.

2.1.2. The Use of Green Roof

One of the goals of implementing green building is to maintain or expand the city’s greenery to improve the quality of the microclimate, reduce CO₂ and pollutant substances, prevent soil erosion, reduce the burden on the drainage system, and maintain a balance of clean water and groundwater systems [7]. Improving the quality of the microclimate around the building, which includes human comfort and habitat, can be accomplished by installing a green roof covering 50% of the roof area that is not used for mechanical electrical (ME) means, computed from the canopy area. Green roofs not only provide a green public space for building inhabitants, but they also provide ecological and environmental benefits. Furthermore, green roofs increase the thermal resistance of the roof, minimizing the heat flow through the roof and into the space beneath.

Green roofs are classified into two types: intensive and extensive. Green roofs that are densely planted are thicker and can support larger plants. However, because intense green roofs add weight and necessitate irrigation and upkeep, most projects opt for the extensive type, where the soil layer is thinner (less than 4 inches) and often made of a lightweight substance such as perlite [7]. The estimation of the total comprehensive wet load of green roofs can range from less than 49 kg/m² to a maximum of 98 kg/m².

2.2. Energy Efficiency and Conservation

Reduced energy use is referred to as energy conservation. The primary purpose of energy conservation is energy savings. Meanwhile, energy efficiency is defined as any approach, technique, or concept that allows for the more efficient use of energy and contributes to a reduction in the global energy demand. Energy efficiency and conservation are efforts to control and save electrical energy through building designs that maximize natural lighting and ventilation, employ energy-saving features, and employ environmentally friendly technologies capable of producing new energy sources for buildings from existing natural resources [35]. Energy efficiency and conservation can drastically lower the operating costs. Such as passive building design (building orientation and shaping to maximize natural lighting, passive cooling and natural ventilation, the consideration of new energy sources (such as the sun and wind), the use of building envelopes, the use of energy management controls to be more efficient (such as automatic sensor lights), and the use of energy-efficient cooling systems). Several points are the use of better insulation, better glass (double glazing, Low-e), more efficient air conditioning, motion sensors to turn on lights and HVAC, naturally maximizing ventilation and illumination, and properly measuring the HVAC system used.

Table 2. Formulation of variables related to energy efficiency & conservation.

Source	Theory	Regarding Design & Material Aspects	Variables
[35]	Better use of insulation, more efficient air conditioning & glass, motion sensor for lighting & HVAC, maximizing ventilation, and natural lighting.	The use of low-E glass material, energy-saving air conditioning, and natural lighting design.	(X5) Use of Low-e glass (X6) Use of energy-saving air conditioning system (X7) Use of a smart lighting system (X8) Use of photovoltaic solar panels (X9) Use of building envelope with secondary skin
[36]	The passive design of buildings (orientation and shaping of buildings to maximize natural lighting, passive cooling, and natural ventilation).	The passive design of the building for natural lighting and ventilation and the use of environmentally friendly technologies.

shows the principles of efficiency and energy conservation.

The next three variables are derived from the concepts of water conservation, material resources and recycling, and indoor air health and comfort.

2.3. Water Conservation, Material Resource & Recycle, and Indoor Air Health & Comfort

Water conservation is an effort to control the use and efficiency of water by saving the use of clean water with efficient features, the use of recycled water installations, the use of rainwater/grey water technology for irrigation and toilet flushing, and regulating the liquid waste treatment. The concept of water conservation can be seen in

Table 3. Formulation of variables related to water conservation.

Source	Theory	Regarding Design & Material Aspects	Variable
[3]	Reduce, reuse, and recycle water.	Use of recycled water	(X10) Use of a recycled water system
[25]	Minimize wasted water, efficient use of fixtures, and use of recycled water.	Use of recycled water
[28]	The use of appropriate water equipment for discharge capacity, and the use of alternative sources of clean water.	Utilization of alternative sources of clean water

.

Meanwhile, material selection can have an impact on the environment because of all the processes involved, such as extraction, production, and transportation, all of which can have a negative impact on the ecosystem. Some of the criteria for the building materials used for green building products in general, including products that are fabricated with efficient processes, including reducing the energy consumption (minimizing waste), materials that can be recycled at the end of their life, components reusable buildings, materials that are more durable than conventional products, and systems that inhibit moisture or biological contamination in buildings. The formula for the variable use of environmentally friendly materials can be seen in

Table 4. Variable formulas related to green material.

Source	Theory	Regarding Design & Material Aspects	Variable
[3]	Minimize energy used.	Environmentally friendly materials.	(X11) Use materials of environmentally friendly.
[25]	Minimize wasted water, efficient use of fixtures, and use of recycled water.	Use of recycled water.
[28]	The use of materials by minimizing the energy used, environmentally friendly and safe.	Safe and environmentally friendly materials.

.

The last variable relates to good air circulation and lighting, controlling temperature comfort, reducing the exposure to cigarette smoke in the room, using non-toxic building materials for occupants, adequate views outside the building, and controlling noise levels. Comfort in the room can be done by avoiding materials that are low in hazardous materials (VOC) in furniture and interior finishing, the use of natural lighting, and good ventilation. In addition, user comfort in the building includes the regulation of the air temperature, air flow, relative humidity, and thermal conditions in the building, and the use of low VOC materials [3], as shown in

Table 5. Formulation of variables related to spatial health and comfort.

Source	Theory	Regarding Design & Material Aspects	Variable
[3]	The right air temperature, stable air flow, and humidity and the use of low VOC materials.	the use of low VOC materials.	(X12) Use of low-VOC materials in wall paint.
[25]	The right air temperature, stable air flow, and humidity and the use of low VOC materials.	use of low VOC materials in furniture/finishing.

.

3. Methods

The two stages of research are applied in this paper. First is the empirical study, and the second is building valuation modelling. The method and process are presented in Figure 2.

3.1. Empirical Study

The first method is an empirical study to confirm the effect of the application of green buildings on the cost of the building’s life cycle and the value of the building. Effect and relationship analysis were used to obtain the confirmed results [32]. The empirical study was conducted in Indonesia with respondents from property development practitioners ranging from CEOs to functional management. The data were collected by a survey method using questionnaires. Then, the data are compiled and analyzed using multi-correlation with regression. The regression models are X1 to X12, regarding the use of the green building concept, and Y1 to Y3 regarding the building’s valuation. Here, the Y1 is the increased construction costs. The Y2 is the reduction in operational costs, and Y3 is the increased property value. So that in this study, there are 3 models of the influence of X1 to X12 to Y1, to Y2, and to Y3, separately. Therefore, the questions in the questionnaire are differentiated according to the three models. There are 12 questions based on 12 variables of X. The questions are in the form of the level of agreement from the respondents about the effect of using the green building concept on a building’s valuation.

3.2. Building Valuation Modelling

The second stage was the cost model to obtain the value of the building. In this paper, the value of the building is carried out using a cost approach based on Life Cycle Cost (LCC). The basic formula is the cost of the land, plus the cost of the construction as an initial cost-plus operation cost, maintenance cost, replacement cost, and energy cost. There are two interdependent variables, namely the depreciation and salvage value. In this model, it is not calculated with the assumption that the ratio of the salvage value to the depreciation is the same between green and non-green buildings. It is also based on the idea that a developer would likely cost a new building or rebuild or reconstruct a property on a comparable piece of land. The formula of LCC that is applied in this paper is:

LCC (PV) = Initial cost
                   + {annual energy cost × [P/A. i%, years]}
                            + {annual operating and maintenance cost × [P/A, i%, years]}
                  + {replacement cost × [P/F, i%, years]}.

(1)

There are two steps in this stage that are the determination of the cost model and the LCC model for the building’s valuation. The two steps are carried out for a comparison between green buildings and non-green buildings. The comparison of the two is done in terms of the LCC and sensitivity.

4. Results

4.1. Profile Respondents

In this study, we obtained 198 respondents. The respondents involved consisted of Project Managers, Design Managers, Property Managers, General Managers, Senior Managers, Board of Directors (BOD), and a Chief Executive Director (CEO) who had and/or are currently directly involved in high-rise building projects in construction management and property development in Indonesia. The data collection process used a questionnaire survey which was given directly to the respondents.

4.1.1. Current Position

This section shows the position of the respondents related to their involvement in the development of green buildings. Based on

Table 6. Profile of respondents.

	Profile Respondent	Percentage	Number
Current position	Project Manager	29%	61
	General Manager	24%	51
	Design Manager	14%	29
	Property Manager	12%	24
	BOD	11%	23
	CEO	10%	10
Type of green building project ever built	Hotel/Apartment	37%	73
	Residential	15%	29
	Office	14%	28
	School/Campus	12%	24
	Mall	12%	24
	Hospital	8%	16
	Etc.	2%	4
Experience of respondent	<5 years	45%	88
	5–10 years	32%	64
	10–15 years	10%	20
	15–20 years	8%	16
	>20 years	5%	10

, as many as 29% of respondents are project managers, as many as 51 respondents or 24% come from general manager, 29 respondents or 14% represent design managers, 24 respondents or 12% are property managers, 23 respondents or 11% represent BOD, and the rest, that is 10 respondents or 10%, are CEOs.

4.1.2. Types of Green Building Project Ever Built

In this question, the respondent could choose more than one answer to the green concept building that has been handled, to find out the respondent’s experience in high-rise building projects and the application of the green building concept. In Table 6, 73 respondents, or 37%, have handled hotels or apartments. As many as 29 respondents, or 15%, have handled residential areas. Twenty-eight people, or 14% of respondents, have been involved in the development of office buildings. A total of 24 respondents, or 12%, have handled buildings on a school/campus and a mall building. A total of 16 respondents, or 8%, have handled a hospital building, and 2% of the respondents have been involved in the development of other buildings. From these results, the most dominant respondents are those who have ever built a hotel and apartment-type building.

Of the many respondents’ involvement in building development, the majority of respondents admitted that green concept development in high-rise buildings is mostly applied to office buildings and malls. This is because the use of energy for large-mass buildings will be more efficient than for certain small units, such as for the use of VRV AC, Low-e glass, and automatic lighting systems. The majority of respondents think that the use of the green concept in buildings such as apartments in Surabaya is still very expensive, so not many are interested in this green concept. In apartment buildings, the application that is often done is through the formation of a mass that extends east–west to prevent the entry of solar heat into the building. The advantage of this application is that the selling price of the apartments in the north–south direction will be more expensive than in the east–west direction.

4.1.3. Experience in Green Building Project

This question is used to find out the experience of the respondents in green building projects. The experience of respondents in green building projects is expected to represent information about the green buildings in Surabaya. Based on the results of the questionnaire survey, as shown in Table 6, as many as 45% of the respondents have under 5 years of experience. A total of 32% have experience between 5 and 10 years As many as 10% of the respondents have 10–15 years of experience. As many as 8% of the respondents have 15–20 years of experience, and 5% of the respondents have worked in green building projects for more than 20 years.

According to the respondents who have 5 years of experience, green building is a new concept known in Indonesia, so the respondents in this group do not have experience in the related fields. The respondents who have experienced from 5 to 15 years think that the green building concept is a must; it is no longer voluntary. This is also approved by the respondents who have more than 20 years of experience in green building development. They mentioned that green building may be expensive at first, but it is a very good investment in the future, especially in terms of protecting the living environment.

4.2. Descriptive Result

An overview of the respondents’ opinions is presented in Figure 3. The frequency shows the number of respondents who choose at the scale level 1–5. Scale 1 indicates the lowest agreement, and scale 5 indicates the highest agreement. The operational definition of each variable, X and Y, is as follows:

X1:

The building has a span that extends vertically (more than 10 floors), not extending any more than 27.5 m, which serves to facilitate cross ventilation in the building.

X2:

The building has a span that extends horizontally (not more than 10 floors), not extending more than 27.5 m, to facilitate cross ventilation in the building.

X3:

Natural lighting is lighting sourced from nature which is commonly known as sunlight. It is viewed from the direction of the opening which mostly faces the north–south side (not in the direction of the movement of the sun). The amount of light that enters is according to the recommended table of daylight factor. For example, for office buildings, the daylight factor for the general room is 1.9%, while for the drawing room it is 3.8%.

X4:

The roof of the building is partially or completely covered with vegetation and growing media, planted on a waterproof membrane. It can also include additional layers such as root barriers, drainage, and irrigation.

X5:

A type of glass that has a low emissivity that can reduce heat from the outside with savings of up to 30%, with a maximum dimension of 2134 mm × 3048 mm.

X6:

Air conditioning system planning must consider the most efficient design. For example, a VRV AC inverter with one outdoor for several indoor units.

X7:

The light is turned off automatically by the motion sensor and lux sensor. Planning artificial lighting in office buildings using dimmers to save electricity consumption.

X8:

Solar panels/solar cells are used for partial lighting (in this case using DC direct current) and require an inverter (battery) to be used to power AC devices.

X9:

The building elements that surround the building are transparent or non-transparent walls and roofs where most of the thermal energy is transferred through these elements. In order to streamline the air conditioning load, the building envelope planning must plan the building envelope by calculating the Overall Thermal Transfer Value (OTTV) not exceeding 45 W/m².

X10:

Serves to treat dirty water and used water so that it can be reused for secondary water consumption (flushing toilet/plant watering system).

X11:

Material that resembles concrete and has strong properties, is water and fire-resistant, durable and is made in a factory, lightens the burden of building structures, and the price is relatively more expensive than red brick.

X12:

If the paint emits a strong odor, it means that it contains high levels of VOCs. If there is an odor but it is not too strong, it means that the paint contains solvent, but it is not too high. Paints that are completely solvent-free should absolutely not emit an odor. Does not contain timbel (Pb) and mercury.

4.3. The Effect on Green Application to Building Valuation

In each aspect of the green building, the impact on the investment will be described. These positive and negative values are to indicate the prediction of the financial variable (Y) by the green building variable (X) or an indication of the shape and magnitude of its influence. A positive number means that if X goes up, Y goes up, and if Y goes down, then X also goes down. A negative value means that if X goes up, then Y will go down, or if X goes down, then Y will go up. The discussion of the results of this confirmatory research on the effect of 12 green building variables (X1–X12) on the finance variable is discussed to be the basis for the assumptions of compiling the cost breakdown structure and the assumptions for calculating the LCC.

The effect of implementing a green building on a building appraisal is presented in order of the 12 variables, as follows.

4.3.1. The Effect of Thin Building Design Vertically (X1)

The formation of a thin vertical building shape and orientation design has the opposite impact of raising construction costs by −0.113. That is, the greater the surface area of the structure that is thin and rising, the lower the rise in the construction costs, and the greater the increase in the construction costs if the surface area of the building is thin and increasing. The level of influence produced (−0.113) by the establishment of a thin vertical mass on the increase in the construction costs are classified as extremely low. A smaller footprint is one of the best construction budget-saving measures, so the smaller the area, the more efficient the use of the energy sources for the building. It is predicted that building prices will rise. The taller the building, the greater the dead load, wind pressure, and earthquake load, which will necessitate a larger foundation and structure, increasing the construction cost. Thus, the best height of the building to maximize the structure and material consumption is roughly 30 floors.

The formation of a thin vertical building shape and orientation design has a positive effect of 0.127 for the decrease in the operational costs; a positive value implies an effect that is in the same direction as the drop in the operational costs. That is, the larger the surface area of the structure that is thin and rising, the lower the operational expenses, and the smaller the surface area of the building that is thin and rising, the smaller the decrease in the operational costs. The level of influence generated (0.127) by the creation of a thin vertical mass is described as low or weak in terms of the decreasing operational costs. The optimal time to incorporate a green design is during the conceptual design phase. A thin building will undoubtedly receive more natural illumination and can be maximized, allowing it to reduce the use of lights in the structure, resulting in a lower power usage. As a result, the operating costs can be decreased [37].

The formation of a thin vertical building shape, on the other hand, has a −0.05 influence on the increase in the property value. That is, the more the surface area of the building that is thin and growing upwards (the number of floors increases), the less the increase in the property value is, and the larger the increase in the property value, the smaller the surface of the building that is thin and rising upwards is. This contradicts the statement that the market price of green concept property is higher than the property that does not apply the Green Development concept. A higher occupancy value and an ease of maintenance make it easier to sell and obtain a higher market valuation. They are also backed by the majority of responders who disagree with these findings. The value of a property in Indonesia increases with the height of the building. The function of commercial structures is to rise above the ground. This is because the more floors that can be built, the more floors that can be sold, and hence the higher the property value.

4.3.2. The Effect of Thin Building Design Horizontally (X2)

In addition to the vertical formation, the production of a thin horizontal building shape has a 0.152 rise in the construction costs. It means that the bigger the surface area of the building that is thin and horizontally stretched (without increasing the number of stories), the greater the increase in the construction expenses. Additionally, the smaller the surface area of the building that is thin and horizontally elongated, the less the increase in the construction expenses. This discovery, however, contradicts the findings that structures with horizontally thinned mass formations can save on initial investment expenses. In this case, the concern is that the smaller the surface area that contacts the site, the more efficient it is in using energy sources for its construction. The most significant user expenses are the beginning costs in the review research [38]. The majority of the respondents agreed with the study’s findings, stating that the increase in the expenses was caused by the rising amount of the site/land used, which increased the land price to be paid, leading the cost to being expensive. The shape that extends to the side will increase the utilization of the system and utility structure.

The formation of a thin horizontal building shape has a unidirectional effect on lowering operational expenses by 0.020, while the larger the surface area of a thin and horizontally elongated building, the lower the cost is. Additionally, the lower the running costs are, the smaller the area of the building that is thin and horizontally elongated is. The smaller the building area, the more efficient the use of energy sources for later building operations are. Many respondents agreed and explained this, who claimed that horizontally thin structures do not require more energy since, in addition to using thin designs, buildings are not excessively tall, therefore less amounts of energy are used when the building functions are lower. The same applies is the case of the utilization of lifts and water pumps. The creation of a thin horizontal building shape and orientation design, on the other hand, has relatively little influence on boosting the property value. The rise is negligible, at 0.005. The findings of this study are consistent with that the green concept is used as a differentiation to stimulate a broader market-driven, and as free promotion. The worth of the property can grow based on the price of the land occupied by the building. Because more and more land is being used, and land prices continue to rise, the selling price will rise as well.

4.3.3. The Effect of Direction of the Opening Area for Natural Lighting (X3)

The direction of the opening area for more natural lighting on the north–south side increases construction costs by 0.009. This indicates that when the number of openings is increased in this direction, the increase in construction is bigger, and when the number of openings is decreased in this direction, the increase in construction is smaller. This discovery contradicts previous results that the position and exterior of building apertures affect the amount of solar radiation entering the building, meaning that the area and location of the openings affect the building’s ability to retain heat [39]. The majority of the respondents agreed with this notion; the lack of many openings in the east–west portion and the extensive use of walls will save money on window frames and glass. This is based on the site’s situation, if it is not possible for the north–east direction to provide openings and be forced to be given openings, which can ultimately increase the construction cost.

The location of this opening area has the opposite effect of decreasing the operational costs by −0.233, which suggests that the decrease in the operational costs will be smaller if additional openings are offered in this direction. Furthermore, the fewer openings there are in this direction, the cheaper the operational costs will be. However, the findings of this study contradict the widely held belief that the correct location for a building is approximately 20 degrees north. Building orientation is critical for energy conservation, as a good building orientation can save a significant amount of energy and reduce carbon production [8]. Many respondents stated that the direction of the opening does not affect the operational costs because it depends on the function of the building, i.e., whether it is an office or a residence. Because office buildings typically employ air conditioning, the orientation of the openings has little effect on their operation.

The direction of this opening area has a −0.258 negative effect on the increase in the property’s value. The negative indicates that when there are more openings in the north–south direction, the increase in the property’s value is smaller, and when there are fewer openings in the north–south direction, the growth in the property’s value is even bigger. This discovery, however, varies in that with the appropriate building orientation, the maximum benefit from the natural heating and cooling design can be realized, which in this case is the direction of openings in the north and south which is appropriate for boosting thermal comfort in the building since it receives less sunshine and has light refraction so that it does not cause a glare for the occupants in it. This concept is supported by the majority of respondents who stated that in Indonesia, the placement of lighting openings depends on the function you want to display. It is more important to have massive walls or openings for lighting. For residential functions, the direction of the north–south opening is more chosen by consumers than the east and west opening, thus making the selling price of the units facing the north–south higher.

4.3.4. The Effect of the Use of a Green Roof (X4)

The use of green roofs/roof gardens has a unidirectional effect on increasing construction costs by 0.099, which means that as there is an increase in the use of green roofs, the increase in construction costs will be greater, and the less the number of uses of green roofs, the smaller the increase in construction costs. This can be explained by the that the installation of a green roof is not cheap, and making a green roof requires careful planning because it requires water tanks, cooling towers, planting space, etc. To make a green roof/roof garden system, a special system is needed so that no water seeps into the roof and floors, thus requiring a very expensive cost to be applied to high-rise buildings.

The use of a green roof/roof garden has a low effect on decreasing the operational costs by 0.365. The wider this green roof is and the more applications it has, the lower the operational costs will be. Additionally, the fewer applications of this green roof, the lower the operational costs will be. Green roofs can improve the insulation quality and reduce temperatures up to 10 degrees, which means a reduction in the cooling requirements and saving energy and money. In addition, the use of green roofs that are longer than conventional roofs also have an effect on saving maintenance costs. For how many savings in terms of the cooling costs can be made depend on the size of the building and the type of green roof. The floor under the green roof will indeed feel cooler than the one without using a green roof because the park can reduce the impact of the heat island effect around it, so that the use of air conditioning can be minimized.

The use of a green roof/roof garden has a direct effect on the increase in the property value by 0.296. This means that the greater the use of the green roof system, the greater the increase in the property value, and the less use the green roof system receives, the smaller the increase in the property value. The use of a green roof/roof garden can increase a property’s value and sell development by functioning as a public space to be used as a communal and entertainment space, which can be used as a recreation area and may contain outdoor areas, swimming pools, observation decks, and other things; this can increase the economic value of the building. In addition, green roofs can also reduce noise pollution around buildings and also improve the air quality around them. Green roofs can increase the selling value of buildings by raising the image of environmentally friendly buildings. In addition, the utilization of green roofs for commercial areas, such as sky dining, can also increase the value of the property.

4.3.5. The Effect of the Use a Low-E Architectural Glass (X5)

The use of Low-e glass material has the opposite effect on increasing construction costs by −0.594, which means that the wider/more Low-e glass is used, the smaller the increase in the construction costs. Additionally, the less Low-e glass which is used, the greater the increase in the construction costs will be. In European countries, reporting the additional investment required to use Low-e glass compared to ordinary glass is on average less than 0.3% of the cost of building new housing, and surcharges have decreased considerably over the last ten years. However, this result is not in accordance with the findings in Indonesia, as the price of Low-e glass is much more expensive than clear glass in general, which can reach 5–10 times the price of clear glass.

The use of Low-e glass material has a positive effect on reducing the operating costs by 0.177. The value is positive, which means that the wider the use of this glass, the lower the operational cost will be, and the less the use of this glass, the lower the operational cost will be. The small SC owned by Low-e glass can cause the external heat load to be smaller so that it will be more efficient for the use of air conditioning, which can reduce the cooling load in the building until it reaches 30%, so as to reduce the use of AC energy. The use of air conditioning in office buildings uses Low-E glass. An opinion states that Low-E glass can indeed reduce heat, but developers in Indonesia still pay less attention to the use of this glass because they are fixated on the use of air conditioning to create a comfortable atmosphere in the room and are constrained by the high cost of glass.

Likewise, the use of this glass increases its property value and has a unidirectional effect of 0.303, which means that the more Low-e glass is used in buildings, the greater the increase in a property’s value, and the less Low-e glass which is used in buildings, the smaller the increase in the property’s value. The increase in the property value from the use of glass is partly because it can reduce condensation problems on window borders, and has a greater flexibility for architects, designers, and users. Additionally, it can be used as a media for the promotion of environmental care. The use of Low-E glass could be used as a property sales strategy, that is selling environmentally friendly concepts in their buildings.

4.3.6. The Effect of the Use an Energy-Saving Air Conditioning (X6)

The use of energy-saving air conditioning (E-save AC) has the opposite effect on increasing construction costs, by −0.369, which means that the more E-save AC units are used, the smaller the increased construction costs will be. Additionally, the fewer the number of E-save AC units which are used, the greater the increase in the construction costs. The total cost of installing an E-save system is 5% to 22% higher than chilled water with an equivalent capacity. However, many respondents did not agree with this result, according to one respondent, in terms of the cost of E-save AC being very much different from ordinary split AC. One of the factors that make E-save AC more expensive is the compressor work system and its more complex piping system.

The use of E-save AC has a unidirectional effect on decreasing the operational costs, by 0.335, which means that the more E-save AC is used, the lower the operational costs will be. Additionally, when air conditioning is used less with an E-save system, the lower the operational costs will be. This is in accordance with the previous concept, that the wattage used by this E-save AC is lower than conventional AC so that it can save electrical energy. In addition, the E-save AC will be easier to maintain because of the centralized system. Savings occur in the efficiency of the ducting used, and the variable speed in each condensing unit makes load sharing more efficient so that it can save the energy being used. This system would be more efficient for commercial buildings such as office buildings or malls.

The use of E-save AC has a positive but very low effect on increasing its property value, amounting to 0.045. This means that the more the E-save AC system is used in the building, the greater the increase in the property value. Additionally, the fewer the number of uses of this E-save AC system, the smaller the increase in the property value will be. This is supported by the use of air conditioning with an E-save system that is more flexible in design, and location placement, and can avoid protruding units that can damage the beauty of the space [6]. Additionally, it is easier for space reconfiguring. In addition, the concept of air conditioning that carries the concept of being environmentally friendly is a very strong image as a promotional medium. For developers, increasing property values with E-save AC is still not considered.

4.3.7. The Effect of the Use a Smart Lighting System (X7)

Besides solar panels, another energy-saving concept is the use of smart lighting systems which have a positive effect on increasing construction costs by 0.074. This means that the more the number of uses of this automatic lighting system, the higher the construction costs will be. Additionally, the fewer the number of uses of this system, the lesser the increase in the construction costs will be. The use of modern lighting systems requires higher costs than conventional lighting systems because complex and modern lighting systems are usually included in the integrated lighting system. Automation systems for smart buildings and the market price are still much more expensive than conventional systems. The majority of respondents also agree with this increase, because the system for its application is more expensive than conventional lighting systems.

The use of smart lighting systems has a positive effect on reducing the operational costs, by 0.227, which means that the more use this system receives, the lower the operational costs will be, and the less use this system receives, the lower the operational costs will be. These results are in accordance with the concept of implementing an artificial lighting system that can save the consumption of electricity by using a smart lighting system. Although there are no exact figures, it is generally estimated that the resulting energy savings can reach 10–30% through self-scheduled controls. Using occupants to control the system can also still create savings. In fact, the energy savings from motion sensors vary quite a lot, and the average savings is 30% for private offices. For large-scale buildings in Indonesia, the use of this automated system would be more effective in saving electricity costs, such as in offices and malls.

The use of smart lighting systems has a positive effect on increasing the value of its property, amounting to 0.181, which means that the more the number of uses the smart lighting systems receive, the greater the increase in the property’s value. Additionally, the fewer the number of uses of this system, the smaller the increase in the property’s value. This result is supported by user productivity which can be increased by optimizing the indoor climate, and long-term investment protection due to maximum flexibility, certified reliability, and long service life. With decreasing utility costs from using this automation system, the operating income in America will increase. Every USD 0.10/ft2 saved in energy can increase the market value of the property by USD 0.80/ft2. Smart lighting systems include promotional media and strategies to highlight the property products made compared to conventional buildings.

4.3.8. The Effect of the Use of PV Solar Panels (X8)

The next green building aspect is the use of solar panels for independent electric power systems which negatively affects the increase in construction costs by −0.119, which means that if the use of solar panels is increasing, the smaller the increase in the construction costs, and the less solar panels are being used, the greater the increase in the construction costs. These results can be explained as follows, in accordance with a literature review which states that the use of this system will increase the initial cost of adding materials and tools to support the panel because it requires a special system and installation in order for the panels to be installed and used. The installation of solar panels will turn into an effective application to provide power to buildings and equipment located far from the existing grid if this system is integrated with the building envelope, such as roofs or windows, so that it can save costs for the system and its installation [40]. The use of solar panels in tall buildings would be very expensive, from the installation system and the price of the panels. In addition, they are of the opinion that the energy produced will not be sufficient to meet the energy needs of the building’s users.

The use of solar panels has a unidirectional effect (0.230) on the decrease in the operational costs. The greater the use of solar panels, the lower the operational costs will be, and the less use solar panels receive, the lower the operational costs will be. According to Li et al. [27], the real benefit of using this is a reduction in electricity bills. In addition, solar panel maintenance is typically done once a year to check for system corrosion, physical damage, or other potential problems, and most of the maintenance is the monitoring system performance. The later use of solar panels when properly utilized would save electricity usage from the PLN/State Electricity Company.

The use of solar panels to increase property values has a positive effect on increasing property values, although it is very low (0.074). This means that the more use solar panels receive, the greater the increase in a property’s value, and the less use solar panels receive, the smaller the increase in a property’s value. There is also a reduction in the operational costs. Installing a photovoltaic (PV) system or solar panels can definitely increase the attractiveness of a building as a promotional medium. A PV system creates an environmentally friendly image for the company so that it can attract potential customers to the products offered. Another advantage is that it also reduces the building’s carbon footprint as it generates electricity without emitting any greenhouse gases or other pollutants. From the results, the majority of respondents agree with this result that solar panels with very expensive prices can definitely increase their property value, by looking at the function and efficiency of the solar panels themselves as independent electrical energy producers.

4.3.9. The Effect of the Use a Building Envelope with Secondary Skin (X9)

The use of a building envelope in the form of a secondary skin has a positive effect on the increase in construction costs by 3.70. This means that the more surface area that uses the secondary skin, the higher the increase in construction costs, and the smaller the surface area that uses the secondary skin, the smaller the increase in construction costs. This result is consistent with a previous theory and research which states that in new buildings, the cost of building envelopes is generally 5% to 25% of the total building cost, and can be higher if certain design criteria are met, such as storm or explosion resistance [41]. Almost all of the respondents agree with this increase, with the consideration that the use of an additional building ‘skin’ definitely increases the construction cost more than those without an additional ‘skin’.

The use of a secondary skin has a positive effect on reducing the operational costs by 0.014. This means that the more secondary skins are used, the lower the operational costs will be, and the fewer secondary skins which are used, the lower the operational costs will be. This is in accordance with Moghaddam et al. [8] who state that the right design and placement will be able to maximize the passive cooling of the building and can save energy use in the building. The majority of respondents agree with this decrease, due to the use of an additional ‘skin’ as a shield, meaning heat from the outside will not enter directly, so, in general, the operational use of electrical energy for the air conditioner can be reduced. In addition, the use of a secondary skin has a very low positive effect on the increase in a property’s value, amounting to 0.101. The larger the surface area that uses the secondary skin, the higher the property value will be. The building envelope greatly affects the performance level of the building in achieving the most cost-effective design. So, the right design can improve the quality and performance of the building. Apart from being a retainer of the sun’s heat in buildings, a secondary skin can be used as a promotional medium and as an addition to the selling value of the property later.

4.3.10. The Effect of the Use a Recycled Water Systems (X10)

The use of this recycled water treatment system has a strong positive effect on increasing construction costs, amounting to 0.724, which means that the larger the size of the water treatment system used, the higher the construction cost will be, and the smaller the size of the water treatment system used, the smaller the construction cost will be. The initial cost of installing this system requires a higher initial cost due to the need for the addition of a new system and the project and arrangement of the greywater system and plumbing equipment that will be used [42]. The cost will be expensive for the water pump and the piping system used to drain water into the bathroom.

The use of this recycled water treatment system has a negative effect on reducing the operational costs (−0.170), which means that the larger the recycled water treatment system which is used, the lower the operational costs will be, and the smaller the recycled water treatment system which is used, the greater the operational costs will be. Even at the time of operation, this system requires a large amount of energy, especially to drain recycled water to flush toilets in high-rise buildings, especially because of the use of the pump. The use of this system in high-rise buildings will increase the use of electrical energy to treat and pump these waters because this system is large enough that it will increase the operational and maintenance costs later. Thus, there are still a few tall buildings that use recycled water systems in Indonesia.

The use of this recycled water treatment system has a positive effect on increasing its property value by 0.027, which means that the greater the use of the recycled water treatment system in the building, the greater the increase in the property’s value, and the smaller the use of the recycled water treatment system in the building, the smaller the property value will be too. Buildings become more environmentally friendly by controlling the waste which is released. Other benefits to the environment include cooling and cleaning the air, reducing the heating and cooling energy costs, beautifying the surrounding environment, and reducing asthma and heat-related diseases. The use of this system can reduce water use and is more efficient in terms of product yields, such as reducing water and fertilizer costs. The Return on Investment (ROI) of the use of greywater management ranged from 3 years and was considered to be economically attractive [43]. The use of the water treatment system is very expensive in operation, so there are still very few high-rise buildings that use this water treatment system in Indonesia.

4.3.11. The Effect of the Use a Material of Environmentally Friendly (X11)

One of the environmentally friendly materials is the lightweight brick wall. The use of lightweight brick walls has the opposite effect of increasing construction costs by −0.147. A negative value means that the more light bricks which are used, the smaller the increase in the construction costs will be. Additionally, the lower the amount of light brick used is, the higher the construction cost will be, as lightweight bricks are relatively more expensive than conventional bricks. However, the overall construction work using conventional bricks is not always cheaper than using lightweight bricks. This statement is supported by the use of lightweight bricks as walls that can reduce the volume of structural elements such as columns, beams, floor plates, and foundations because the load that supports them is light. Additionally, the construction is relatively simple, and it is more economical when transporting to the site and reducing human labor so that it can reduce the costs incurred for the use of building structures or for the calculation of the foundation. In Indonesia, installing lightweight bricks can save time on the project, the labor used in the masonry, as well as the savings in the plaster used.

From the results of the analysis, the use of light brick walls has a very low effect (−0.088) on the decrease in the operational costs. That is, the lightweight bricks are used, the smaller the decrease in the operational costs will be, and the less light bricks are used, the lower the operational costs will be. This result is not in accordance with the findings which state that the cost of wall maintenance is more efficient because it has a low water absorption and is resistant to water seepage so that the walls are not easily moist and are safe for wall paint and wallpaper. Additionally, operational costs are more efficient because they are able to withstand the scorching heat of the sun, thereby saving energy costs for daily operations. Lightweight bricks can make walls more susceptible to water corrosion and cracking if the plastering used is not done properly.

The results of the study stated that the use of lightweight bricks had a very low effect on increasing the property value (0.0007). Although very small, this positive effect means that the more light bricks are used in tall buildings, the greater the increase in the property value, and the less light bricks are used, the smaller the increase in the property value. This is based on the significance of reducing the weight of the building without sacrificing the strength, allowing for the reduction in dead loads, which is very useful for structural reasons, for reducing the large dimensions of a steel reinforcement in buildings [41]. In addition, the application benefits walls that require a good insulation. Lightweight brick is thermal insulation that is able to withstand the heat and scorching sun outside the room, and the room is cooler than conventional brick walls even without air conditioning. Because lightweight brick is not only airtight but also watertight, there is little possibility of water seepage in the building, which in this case will provide its own comfort for living and activities and has a good resistance to earthquakes. Using lightweight bricks can increase the value of their properties, such as for residential functions, and lightweight bricks make the selling value slightly higher.

4.3.12. The Use of a Low-VOC in Wall Paint (X12)

The use of low VOC wall paint has a negative effect on the increase in construction costs by −0.0015, which means that the more paint is used, the smaller the increase in the construction costs, and the less paint is used, the greater the increase in the construction costs. The costs used for low-VOC wall paint will be at least more expensive because the quality of the paint is the main factor in the price; the price is still quite high because the market is still not commonly available. This is due to changes in the mixture in the paint composition. The use of this paint on high-rise buildings in Indonesia in particular is still not considered for its impact on users, other than because the price is more expensive than ordinary paint.

The use of low VOC wall paint has a negative effect on reducing the operational costs by −0.370, that the more the number of uses of this paint receives, the lower the operational costs will be, and the less use this paint receives, the lower the operational costs will be. The paint has a resistance and the use of this paint does not significantly affect the operation of high-rise buildings, but its maintenance can be minimized due to the durability of the paint. In Indonesia, the use of wall paint with low VOC labels on high-rise buildings by this developer is still not being considered.

However, the use of low VOC paint has a positive effect on increasing the property value by 0.320. Although it is classified as a weak effect, the more uses low-VOC wall paint receives in the building, the greater the increase in the property value, and the less uses of low-VOC wall paint there is in the building, the smaller the increase in the property value. By choosing a material with a lower level or no VOCs, one of which is the use of wall paint, health problems can be avoided and the need for air purifiers is reduced. The comfortable use of indoor space can increase employee productivity. In Indonesia, developers are still less interested in the use of this paint, especially in apartment buildings where consumers usually do not pay attention to the type of paint used and are more concerned with the facilities.

4.4. The Result of the Effect to Building Valuation

Regarding the 12 variables for implementing green building in high-rise buildings, the aspect that has a positive or direct effect on increasing construction costs in Indonesia are the thin horizontal building shape and orientation design, the direction of the area of natural lighting openings being more on the north–south side, the use of secondary skins, the use of smart lighting systems (motion sensors/lux), the use of recycled water treatment systems for flush and irrigation, as well as the use of green roofs, the use of thin vertical building shape and orientation design, the use of lightweight brick walls, the use of light-weight bricks, the use of solar panels, the use of E-save AC, the use of Low-E glass, and low VOC wall paints have a negative or opposite effect on increasing the construction costs.

Operational and maintenance costs in high-rise buildings with the green building concept according to developer practitioners in Indonesia can be reduced or have a positive value with the formation of a thin vertical or horizontal building shape, the use of a secondary skin, the use of solar panels, the use of smart lighting systems, the use of E-save AC, the use of glass, the use of Low-E, and the use of green roofs. While the direction of the openings on the north–south side, the use of lightweight brick walls, the use of a recycled water system, and the use of low VOC paint have a negative or opposite effect on the operational decline.

The increase in the property value in high-rise buildings with the green building concept, according to developer practitioners in Indonesia, can be increased by using almost all of the 12 green building variables, except for the use of thin vertical building formations and the direction of natural opening areas which are mostly on the north–south side. The resume of the result of the discussion is presented in

Table 7. Influence of green building application on building cost and valuation.

Code	The Variables of Green Building Applications	The Variables of Building Valuation (Y)
		Increased Construction Costs (Y1)	Reduction in Operational Costs (Y2)	Increased Property Value (Y3)
X1	Thin building design vertically	−	+	−
X2	Thin building design horizontally	+	+	+
X3	The direction of the opening area for natural lighting	+	−	−
X4	The use of green roof	+	+	+
X5	The use of Low-E architectural glass	−	+	+
X6	The use of energy-saving air conditioning	−	+	+
X7	The use of a smart lighting system	+	+	+
X8	The use of solar panels	−	+	+
X9	The use of building envelope with secondary skin	+	+	+
X10	The use of a recycled water system	+	−	+
X11	The use materials of environmentally friendly	−	−	+
X12	The of low-VOC materials in wall paint	−	−	+
+ show a direct influence		− show the opposite influence

.

5. Discussion

5.1. The Influence of Green Building Application on High-Rise Building Life Cycle Cost

The comparison between green and non-green building valuation can be conducted in terms of the building’s cost and sensitivity. It is based on the assumption that the land valuation is the same. In this paper, the comparison is made to a high-rise building in Indonesia that functions as a commercial property. The Cost Breakdown Structure (CBS) is a hierarchical representation of the project costs. It represents the cost of the components in the Work Breakdown Structure (WBS). The CBS is an important tool in the financial aspect of a project. Figure 4 presents the CBS of typical green buildings in Indonesia.

The LCC comparison between green and non-green buildings of a commercial property is presented on

Table 8. The calculation result of LCC.

Study Title: Commercial Building MARR (Minimum Attractive Rate of Return) is 6%, Life Cycle is 10 Years, and Present Time is Year 2022		Estimated Cost (USD)
		Green	Non-Green
Initial Cost	Planning cost	343,349	343,349
	Land cost	10,477,161	10,477,161
	Building cost	13,733,960	8,550,350
	Fixed equipment cost	961,377	961,377
	Cost of green building features	3,518,189	0
	Professional service	1,510,350	1,200,000
	Mobile equipment costs (furniture)	2,060,094	2,060,094
	Administration cost	1,258,625	1,258,625
	Other costs	3,775,875	3,775,875
	Total initial cost	37,638,981	28,030,670
Energy Cost	EE lighting cost	103,499	425,000
	Daylighting cost	52,725	471,278
	Cost of AHU fans	193,816	325,000
	Cost of air-con system	15,134	2,134,000
	Cost of water usage	3373	1,316,500
	Total energy cost	368,550	4,671,778
Operation and Maintenance Cost	Operational cost	760,500	3,250,000
	Cleaning fee	5,003,736	6,350,000
	Costs of work safety and security	1,072,229	1,505,000
	Building equipment maintenance costs	2,621,004	4,779,718
	Cost of environmental control	1,429,638	5,213,765
	Cost of garden maintenance (green area)	1,072,229	1,072,229
	Rainwater harvesting maintenance costs	1282	20,235
	Total operational and maintenance cost	11,960,840	22,190,947
Replacement cost	Energy equipment replacement	6177	326,000
	Water equipment replacement	1282	82,000
	Environmental control replacement	540	5400
	Other replacement		2,494,273
	Total Replacement cost	13,226	3,503,833
LCC	Total Life Cycle Cost (Present worth)	49,981,597	58,397,229

. The cost difference between green and non-green buildings can be explained from the examples of each category as follows. For the initial cost category, the examples are building costs and the costs of green building features. For building costs, a green building is 60% greater than a non-green building. This is due to the consequences of different building elements. Meanwhile, for the cost of green building features, there is no cost for non-green buildings. For the energy category, an example of a difference in the costs is the cost of an air-con system. The difference is extreme, this is because in green buildings, green features are used which save energy and even produce energy, for example, with the use of photovoltaics. Meanwhile, a non-green building uses a 100% conventional system. For the category of operational and maintenance costs, the difference between green and non-green buildings is not as big as in the other categories. In the replacement cost category, almost all the cost components have a large difference between the green and non-green buildings. An example is the cost of replacing the energy equipment. The costs for non-green buildings are much higher due to the use of conventional energy equipment, which the elements and components of have a short technical life, which causes a frequent replacement and increases the costs.

The recapitulation is presented in

Table 9. LCC of green building.

Cost Category	Green Buildings		Non-Green Buildings
	LCC (USD)	%	LCC (USD)	%
Initial cost	37,638,981	75.27%	28,030,670	48%
Energy cost	368,550	0.7%	4,671,778.33	8%
Operational and Maintenance cost	11,960,840	24%	22,190,947.1	38%
Replacement cost	13,226	0.03%	3,503,833.75	6%
Total	49,981,597	100%	58,397,229.2	100%

with the comparisons of non-green buildings. Non-green LCC is calculated in the same way under the assumption of the basic cost of a high-rise building. Some examples of building features as a comparison between green buildings and non-green buildings are presented in

Table 10. Building features of green and non-green buildings.

Features	Green		Non-Green
	Illustration	Average Initial Cost (USD)	Illustration	Average Initial Cost (USD)
Roof	Green roof	USD 22,000 150 m2	Conventional roof	USD 8000 150 m2
AC	E-save AC VRV System	USD 25,000 150 m2	Conventional System	USD 4000 150 m2
Lighting	Smart lighting (Smart LED) system	USD 2400 150 m2	LED conventional system	USD 670 150 m2

.

Figure 5 shows the different LCC models between green and non-green buildings. The differences in the percentage of initial cost and maintenance/operation cost. The highest cost for green building is in initial cost meanwhile the non-green is in operational and maintenance costs. In the model of LCC, one of the most important ways to understand uncertainty is sensitivity.

Table 11. Sensitivity of green building.

i	% Cumulative Change in i	Green Buildings		Non-Green Buildings
		Total LCC (USD)	% Cumulative Change LCC	Total LCC (USD)	% Cumulative Change LCC
7.80%	30%	49,939,970	−5.20%	66,497,954.37	7.4%
7.20%	20%	49,953,245	−3.50%	61,916,158.64	−4.1%
6.60%	10%	49,967,109	−1.80%	59,477,577.94	−1.85%
6.00%	0%	49,981,597	0.00%	58,397,229.20	0.00%
5.40%	−10%	49,996,743	1.90%	57,252,643.51	1.96%
4.80%	−20%	50,012,586	3.80%	55,594,162.20	4.8%
4.20%	−30%	50,029,164	5.90%	53,783,848.09	7.9%

present the sensitivity of interests (i%). It means that how LCC is influenced by the change in interest. Figure 6 illustrates the comparison of sensitivity between green and non-green buildings.

Equation:

Y = 18.586 − 3.071X1 (green)

(2)

Y = 24.298 − 4.018X2 (non-green)

(3)

Observing the two graphs, it is seen that non-greens are more sensitive to changes in the cost of capital. This means that changes in cost capital at the same value will have a greater influence on changes in the value of buildings to be non-green compared to green buildings.

5.2. The Influence of Green Building Applications on High-Rise Building Valuation

5.2.1. Analysis of the Effect of the Implementation of Green Building Concept on the Increase in Construction Costs

Based on hypothesis testing, it was found that all green building variables have an effect on increasing the construction costs together. With the results of hypothesis testing for the effect of the green building variable on the partial increase in construction costs, it was found that only the X9 variable, that is “The use of clean wastewater treatment systems, which are recycled for toilet flushes, for garden irrigation” have an effect on increasing the construction costs.

In general, the level of closeness of the relationship between the effect of the application of green building aspects and the initial cost of high-rise buildings is quite large, specifically 77%. While the ability of the criteria for the green building concept in explaining how it affects the increase in the investment costs is also quite high, at 59%, the remaining percentage is the influence of other factors not included in the research model. The results of the classical assumptions in the analysis found that in the normality test, the data tested were normally distributed. In the results of the autocorrelation test, it was found that there was no autocorrelation. The results of the multicollinearity test on the green building variable indicated that there was no multicollinearity or correlation between the green variables.

This green building variable is more accurate in predicting the construction costs because the standard error of the estimated construction cost variable is 0.900, where this value is smaller than the standard deviation of 1.15. That is, the smaller the standard error value compared to the standard deviation value, the better the model used. Variations (big-small or up-down) from the increase in the investment costs, which are worth 49.05, partly come from the green building variable which was studied, which is 28.78, and the remaining 20.26 is caused by other variables that also affect the increase in the construction costs, but were not included in the studied model.

5.2.2. Analysis Effect of the Implementation of Green Building Concept on Reducing Operational Costs

Basically, the level of the closeness of the relationship between the effect of the application of green building aspects with building operational costs is quite high, that is 0.62%. The ability of the criteria for the green building concept in explaining how it affects the limiting of the reduction in the operational costs, with a percentage of 38%, where the value of the coefficient of determination is relatively small. Another criterion consideration is to look at the results of the classical assumptions through the normality test of the data. These results indicate that the data are normally distributed. In the results of the autocorrelation test, it was found that there was no autocorrelation, and there was also no symptom of multicollinearity or correlation between the green variables. Furthermore, the green building variable is more accurate in predicting the construction costs because the standard error of the estimated construction cost variable is 1.325, where this value is smaller than the standard deviation of 1.384. This means that the smaller the standard error value is compared to the standard deviation value, the variation (big–small, up and down) of the model to explain the decrease in the operational costs is getting better.

5.2.3. Analysis Effect of the Implementation of Green Building Concept on Increasing Property Value

To find out that the twelve green building variables can explain and predict the variable model, hypothesis testing is carried out. Based on the test results, all green building variables have an effect on increasing the property values together. However, partially, there is no effect of each variable on the increase in the property values. In general, the level of closeness of the relationship between the concept of green building and the increase in property values in high-rise buildings is strong, that is 82%. While the ability of the criteria of the green building concept in explaining its effect on increasing property values is quite large, which is 67.5%, the remaining percentage is the influence of other factors not included in the research model. The results of the classical assumption test found that the data were normally distributed in the data normality test. In the results of the autocorrelation test, it was found that there was no autocorrelation, and there were no symptoms of multicollinearity or correlation between green building variables. The standard error value of the estimated property value increase variable is 0.819, smaller than the standard deviation value of 1.182. The green building variable is more accurate in predicting property values. The variation (big–small, up and down) of the increase in the property value with a value of 51.71 partly comes from the green building variable studied, which is 34.9, and the rest is caused by other variables that also affect the increase in the property value, but are not included in the model researched.

6. Conclusions

The increase in property values in high-rise buildings in Indonesia can occur by decreasing the operational and maintenance costs as well as increasing the construction costs, such as using a horizontal thin building shape and orientation designs, building envelopes with secondary skins, smart lighting systems (motion/lux sensors), and the use of green roofs. The increase in the property value also occurred with the decrease in the operational and maintenance costs and construction costs that did not increase with the use of solar panels, the use of energy-efficient air conditioners with VRV systems, and the use of Low-E architectural glass. However, the use of more natural openings on the north–south side will prevent property values from increasing, construction costs from increasing, and operating costs from not decreasing.

The study that discusses the effect of applying the green building aspect is still relatively general in high-rise buildings. The findings in this study can contribute to strengthening the concept of the building life cycle cost and the valuation of green buildings. Contributing to strengthening the concept of reducing the operational and maintenance costs obtained from combining material resistance and design that extends the life of the building system and the building itself, energy savings for its operations of 10–15% also clarify the property values. The model of investment decisions for green building can be an interesting and important topic for future research. Next, stakeholder management design is expected to start more aggressively promoting the importance of implementing the green building concept, as well as making building owners more aware of incorporating the green building concept into their buildings.