Passivhaus

Round 1

Reviewer 1 Report

Actual topic.  however it based on very limited number of literature sources. Also many of them are outdated and do not provided any latest information on technology used in modern  PH  and real data (energy consumption ) achieved in PH.

There are at least 5900 research papers in 2020 on PH topic in ScienceDirect database.

So more careful review work should be done in order to bring extra value to this paper.

Author Response

Thanks very much for your feedback. Through your feedback and the journal guidelines, after consulting with the editors, the manuscript type was updated to 'Entry', whose main form of expression is definition and explanation. Additionally, recent references (from the last 5 years) were added to review the performance of Passivhaus buildings with up to date data achieved in modern Passivhaus buildings.

Nonetheless, the following text was added to address your feedback:

L10-12: This article aims to introduce the Passivhaus background, development and the basic design principles for design. Finally, it also presents a brief description of the performance of Passivhaus buildings.

L69-72: This article aims to define the Passivhaus background, design concept and principles, as well as presenting an overview of the studies that had shaped the Passivhaus. Finally, it briefly presents the performance of Passivhaus buildings, although it is not intended as an exhaustive literature review.

L290-317:

4. Passivhaus performance

In its origins, the Passivhaus standard was optimised as a design strategy for heating-dominated central- and northern-European climates. The main objective was to reduce the energy consumption to needed to heat the building comfortably without using conventional heating systems. Nowadays, the Passivhaus standard has been extended to other countries, such as Mexico [29], Chile [30], China [31], the USA [32] and other warm climates [33], with different climates as those in Europe. Several studies had studied the performance of the building fabric in Passivhaus dwellings showing a minimum performance gap between ‘as designed’ and ‘as constructed’ measurements [34]–[37].

The strict guidelines of the Passivhaus standard deliver low-energy homes, which although there is still evidence of deviation from the design intent, the magnitude and extent of the gap were small [38] when compared to non-Passivhaus dwellings. The most common performance gaps between ‘as designed’ and ‘as constructed’ were observed in airtightness—Passivhaus (+0.05 m³/h/m²@50Pa of ‘as designed’) vs non-Passivhaus (+1.3 m³/h/m²@50Pa)—,  walls—Passivhaus (+0.03 W/m²K) vs non-Passivhaus (+0.14 W/m²K)—, roof—Passivhaus (+0.04 W/m²K) vs non-Passivhaus (+0.10 W/m²K)—and hole heat loses—Passivhaus (+2.5 W/K) vs non-Passivhaus (+20.6 W/K). Another study that evaluated 97 UK Passivhaus dwellings suggests that the mean heating demand is 10.8 kWh/(m²a)—‘as constructed’ measurements—with no statistical difference compared to those predicted 11.7 kWh/(m²a) [34], which is considerably low to the UK average dwelling heating demand (145 kWh/(m²a)) and the predicted in build homes (50 kWh/(m²a)).

Although the Passivhaus standard proved to be a reliable design method for low-energy homes with a minimum of performance gaps, the construction of Passivhaus dwellings is widely perceived to have a cost premium in homes built to this standard [7], [39]. However, the Passivhaus ‘cost premium’ may not always be significant and has the potential to achieve adequate levels of indoor environment quality [19]. Nonetheless, one of the biggest concerns about Passivhaus is a greater perceived risk of overheating compared to less insulated homes [19], [20]. However, there is not a significant difference between overheating frequency measured in Passivhaus and non-Passivhaus dwellings [40]. Moreover, recent works provide evidence against overheating that Passivhaus through modelling [41] and physical measurements [42].

Reviewer 2 Report

This manuscript is a review of the passive houses. It introduces the Passivhaus background, development and the basic principles for design.

It is interesting and current topic. The manuscript is well-written and has a logical structure. I have some comments and questions.

1. L35 and L173: “Error! Reference source not found” – Please correct them.
2. Section 2.1. What is the recommended value for the A/V ratio?
3. Section 2.2. What is U-values? Can you give some examples for the insulation’s material?
4. Line 94: Which company is the developer of THERM software?
5. Line 107: “filled with different gases.” Can you give some examples of these gases?
6. Section 2.4. What is the range the optimal size for windows and doors?
7. Section 2.5. Can you write some details about the n50 test? (1-2 sentences)

Author Response

Thanks very much for your feedback. Below the answer to your points:

1. L35 and L173: “Error! Reference source not found” – Please correct them.

L36 - Reference to Table 1 added.

1. Section 2.1. What is the recommended value for the A/V ratio?

L77-79 - Text added:

Hence, the A/V ratio will change as the building does. Hence smaller buildings[1] usually have higher A/V ratios (1.1-1.3 m²/m³) while bigger buildings[2] have lower A/V ratios (0.46 m²/m3).

1. Section 2.2. What is U-values? Can you give some examples for the insulation’s material?

U-values described previously in L80 when the term appears the first time.

L95-96 Text added:

…of mineral wool, polystyrene, polyurethane foam or cellulose. Other materials such as 500 mm thick straw-bale walls or vacuum insulation, which tends to be thinner but expensive

1. Line 94: Which company is the developer of THERM software?

L106 – Text added:

…developed by Lawrence Berkeley National Laboratory [15].

1. Line 107: “filled with different gases.” Can you give some examples of these gases?

L120 – Text added:

… with inert gas, such as Argon or Krypton

1. Section 2.4. What is the range the optimal size for windows and doors?

L128-131 – Text added:

It is important to note that windows are critical to balance overheating in summer and heat gains in winter. Although their size varies with the design of each project, a ‘standard size’ for the component certification is 123 x 148 mm.

1. Section 2.5. Can you write some details about the n50 test? (1-2 sentences)

LL153-156 – Text added:

and measures air leakage through the building. The n50 test creates a differential pressure of 50 Pa between the outside of the building and the inside through a blower door test. The blower door test involves placing a compressor into a building opening (i.e. a door or a window), sealing the ventilation inlets and exhaust to create an underpressure inside the building to identify leakages [1].

[1] Approximate size 8 x 8 x 8 m. External area: 384m²; Internal volume 343m².

[2] Approximate size 16 x 16 16 m. External area: 1536m²; Internal volume 3375m².

Round 2

Reviewer 1 Report

accept as it is