Evaluating Climate Change Adaptation in Vernacular Dwellings: Thermal Comfort and Ventilation of Yikeyin in Haiyan Village, Kunming

Abstract

In response to global climate change, harnessing the climate-adaptive wisdom of vernacular dwellings is crucial for sustainable architectural design. This study takes Haiyan Village in the Kunming plateau area as a case study, focusing on three typical vernacular dwelling types of Yikeyin—‘Half seal’, ‘One seal’, and ‘Two seals’. Using Ladybug and Honeybee within the Rhino Grasshopper platform, a quantitative comparative analysis was conducted to evaluate their natural ventilation efficiency (characterized by Air Changes per Hour, ACH) and indoor thermal comfort (characterized by Predicted Mean Vote, PMV, and Predicted Percentage of Dissatisfaction, PPD). The results indicate the following: (1) Throughout the year, the ‘Two seals’ dwelling type exhibits the most stable diurnal temperature variation, while the ‘Half seal’ dwelling type shows the greatest fluctuation in its diurnal temperature range. (2) The summer ACH values for ‘Half seal’, ‘One seal’, and ‘Two seals’ dwelling types are 3.8~4.5, 1.5~2.9, and 0.8~1.6, while the winter values are 1.9~2.6, 1.3~1.8, and 0.7~1.0. The ventilation efficiency in summer is generally higher than that in winter, and it shows a significant decreasing trend as building volume increases. (3) The summer PPD values for ‘Half seal’, ‘One seal’, and ‘Two seals’ dwelling types are 12%, 18%, and 35%, while the winter values are 22%, 15%, and 12%. (4) The ‘One seal’ dwelling type exhibits good ventilation and thermal comfort throughout the year. The ‘Half seal’ demonstrates the best ventilation and thermal comfort in summer but poorer thermal comfort in winter. The ‘Two seals‘ dwelling type achieves the best thermal comfort in winter, but lower ventilation efficiency, while in summer, both thermal comfort and ventilation are poor. This study not only addresses the gap in the quantitative assessment of climate adaptability in vernacular dwellings but also provides critical data support and a theoretical basis for the scientific preservation, adaptive renewal, and sustainable inheritance of vernacular architecture in the context of climate change.

1. Introduction

1.1. Research Background

Global climate change has been recognized as one of the most severe and far-reaching environmental challenges of the 21st century [1,2]. The Sixth Assessment Report by the United Nations Intergovernmental Panel on Climate Change (IPCC) [3] reveals that since the Industrial Revolution, the global average surface temperature has risen by approximately 1.1 °C and continues to climb, leading to a dual increase in both frequency and intensity of extreme weather events such as heatwaves, severe droughts, and storms [4,5]. These phenomena not only threaten human health and ecological security but also profoundly alter thermal-humidity conditions in living environments, posing external challenges to architectural design, urban planning, and energy utilization models [6]. As both a major source of greenhouse gas emissions and a critical field for climate action, the construction industry faces dual responsibilities [7]. How to reduce carbon emissions while enhancing environmental resilience and thermal comfort in building designs has become a central issue in international architecture and sustainable development research [8].

Among various climate adaptation strategies, traditional vernacular architecture—rooted in long-established regional climate wisdom—is regaining attention [9,10]. By leveraging local natural conditions and resource availability through site selection, spatial organization, and material construction, these buildings effectively adapt to temperature and humidity variations, creating comfortable living spaces with minimal energy consumption [11,12]. This kind of passive design, based on experience and environmental feedback, has been the focus of many studies [13]. Taking the southwestern region of China as an example, many vernacular dwellings ingeniously utilize natural ventilation, shading, heat storage, and other methods through unique site selection, orientation, layout, materials, and construction techniques to create relatively comfortable indoor environments under resource-scarce conditions [14,15]. However, with the acceleration of modernization, these precious traditional vernacular architecture and the ecological wisdom they embody are at risk of being forgotten or destroyed [16,17].

Existing research predominantly focuses on qualitative descriptions or single-season analyses, lacking a systematic quantitative assessment of the relationship between building forms and climate adaptability, particularly for vernacular dwellings in plateau regions [18,19]. And few studies combine it with future climate scenario predictions to evaluate its adaptability under changing climatic conditions [20]. Against the backdrop of global climate change, re-examining, scientifically evaluating, and inheriting the climate-adaptive strategies of vernacular architecture not only holds significant importance for cultural heritage preservation but also provides valuable inspiration for exploring low-energy consumption and sustainable architectural futures.

1.2. Villages Around Dianchi Lake, Kunming, Yunnan

Located in the low-latitude plateau of southwest China, Kunming City in Yunnan Province is situated between north latitude 24°23′–26°22′ and east longitude 102°10′–103°40′, with an altitude of approximately 1900 m. It exhibits typical subtropical plateau monsoon climate characteristics: the temperature fluctuation is not significant in different seasons but there are significant diurnal temperature differences, and intense solar radiation throughout the year. Figure 1 shows the enthalpy and humidity chart of Kunming City based on hourly data, with the horizontal axis representing dry bulb temperature and the vertical axis representing humidity radio. Each small dot on the graph represents the air state at a specific moment in the 8760 h of a year in the Kunming area (i.e., the temperature and humidity combination at that moment), and the color block represents the number of hours in a year that fall within the range. It is known that for most of the year, the dry bulb temperature of the air is between 16 and 24 °C and the humidity is in the range of 30–40%, indicating a relatively mild climate.

Kunming is also renowned for Dianchi Lake, a large freshwater wetland on the plateau. Dianchi Lake has a significant impact on the wind environment, humidity, and temperature regulation of the surrounding areas, forming a heterogeneous thermal environment compared to other high-altitude cities. This lakeside plateau climate poses special requirements for the structure, ventilation strategy, and enclosure performance of residential buildings, leading to the formation of differentiated and refined climate response patterns in traditional vernacular buildings during long-term adaptation. The villages distributed around Dianchi Lake are an important part of the formation of traditional settlements in Kunming. Under the dual influence of agricultural civilization and lake ecology, they have gradually developed settlement patterns and architectural types that are highly coupled with climate. Among them, Haiyan Village, located on the east bank of Dianchi Lake, has preserved the Yikeyin. As is shown in Figure 2, 54% of the types of buildings in Haiyan Village are historical buildings, 63% are two-story buildings, and 50% are brick and soil structure buildings. The proportions of ‘Half seal’, ‘One seal’, and ‘Two seals’ dwellings in Haiyan Village are 25%, 35%, and 10%, respectively (Figure 3).

1.3. Overview of Yikeyin in Haiyan Village

Yikeyin is a highly representative vernacular residential type in Yunnan Province, named for its square shape and orderly layout resembling a seal. This type of courtyard style residence is characterized by a square layout and a surrounding spatial organization, consisting of a principal room, side rooms, inverted seats, and a gatehouse. The central courtyard is the core space for lighting, ventilation, and microclimate regulation. The differences in courtyard proportions, opening arrangements, and volume composition may lead to significant differences in indoor microclimate performance and climate adaptation capabilities. Depending on scale and spatial configurations, various variants such as ‘Half seal’, ‘One seal’, and ‘Two seals’ have been derived (Figure 4, Figure 5 and Figure 6). The smaller ‘Half seal’ dwelling type usually has only one side room, and the ‘Two seals’ dwelling type is formed through splicing or expansion equivalent to the juxtaposition or more complex combination of two ‘One seal’ units.

Yikeyin is a two-story vernacular dwelling with Chuandou timber framing, surrounded by earthen walls or green brick walls, most of which are civil structures. The principal room is slightly higher, with a double slope gable roof. The roof is made of grey tiles, and the side room roof is an asymmetric slope gable roof, divided into long and short slopes. The long slope faces inward and the short slope faces outward, which can raise the height of the external wall, which is conducive to wind prevention, fire prevention, and theft prevention. The surfaces of each roof do not intersect with each other. Both the columns and the door are wooden structural elements. The ground foundation is made of a ‘three-in-one mud’ mixture of lime, tung oil, and porcelain powder, which makes the ground smooth and lustrous yet non-slip, cool and dry yet resistant to moisture (Figure 7).

1.4. Research Objectives

This study selects three typical dwellings—‘Half seal’, ‘One seal’, and ‘Two seals’—in Haiyan Village as research subjects, aiming to reveal the impact of different scales and configurations on indoor microclimates through quantitative analysis. The primary objectives of this study are to quantify and evaluate the climate adaptability of vernacular dwellings within the context of climate change. Specifically, to quantify the natural ventilation efficiency of the three vernacular dwelling types under typical climatic conditions in Kunming using architectural performance simulation software (such as Ladybug and Honeybee within the Rhino 6 Grasshopper platform). Secondly, we aim to assess indoor thermal comfort levels across different seasons for these dwellings, identifying potential risks of overheating or undercooling. Thirdly, we aim to compare differences in ventilation and thermal comfort between the three dwelling types, exploring how building scale and spatial organization influence indoor microclimates. Lastly, we aim to examine the adaptive potential and limitations of these vernacular dwellings in addressing future climate challenges, providing scientific references for the preservation, utilization, and sustainable design strategies of vernacular architecture. Through quantitative evaluation, this study fills the research gap in the existing literature by providing a systematic analysis of vernacular dwellings’ climate adaptability and predicting their performance under future climate scenarios, offering new insights and data support for assessing the climate resilience of vernacular architecture.

1.5. Structure of the Paper

The subsequent arrangement of this article is shown in Figure 8: Section 2 reviews the relevant research literature, including studies on the climate adaptability of vernacular architecture, natural ventilation, and thermal comfort, building performance simulation methods, and the impact of climate change on architecture. Section 3 provides a detailed introduction to research methodologies, covering subject selection and modeling, simulation software and parameter configuration, as well as meteorological data sources. Section 4 presents and analyzes simulation results, including assessments of ventilation performance and thermal comfort. Section 5 delves into the research findings, analyzing the adaptive potential and challenges of traditional vernacular dwellings within the context of climate change, while exploring both theoretical and practical implications of the study. Section 6 summarizes the paper and puts forward the research conclusions and future prospects.

2. Literature Review

2.1. Climate Adaptation of Traditional Vernacular Architecture

Traditional vernacular architecture has long served as a manifestation of the interaction between regional climate, culture, technology, and available materials. Existing research indicates that traditional buildings not only effectively adapt to local climate variations but also maximize resource utilization and minimize energy consumption through rational layout, construction materials, and design strategies. For instance, thick walls and small windows in the Middle East provide efficient insulation and ventilation (Hosseini et al., 2016) [21]. Traditional courtyard houses in northern China utilize rammed-earth walls for winter insulation (Li et al., 2022) [22]. Meanwhile, buildings in the water towns of Jiangnan regulate indoor temperature and humidity through shallow courtyards and water systems (Xiong et al., 2025) [23]. These strategies, rooted in long-term environmental feedback and accumulated experience, largely based on the principles of passive design, are effective in minimizing energy consumption while utilizing local resources.

However, while these studies emphasize the environmental advantages of traditional designs, they tend to focus on isolated building types or individual case studies, offering limited comparative analyses between different building variants or scales within the same region. Furthermore, there is a notable absence of comparative studies specifically focusing on traditional dwellings in high-altitude regions. Moreover, the existing literature often lacks comprehensive systematic assessments and evaluations of how these buildings’ adaptive potential may vary under future climate scenarios, particularly in terms of their long-term viability and ability to handle more extreme weather events (Yang, Liao, et al., 2025) [24,25]. This gap in knowledge highlights the need for more rigorous, comparative studies that quantitatively assess the performance of various traditional dwelling types under projected climate changes, which this study aims to address.

2.2. Natural Ventilation and Thermal Comfort

Natural ventilation is widely recognized as a crucial strategy for enhancing indoor air quality, regulating temperature and humidity, and reducing energy consumption in buildings. Research indicates that factors such as building orientation, window placement, interior spatial layout, and external wind conditions significantly impact a building’s natural ventilation efficiency. Although numerous studies have utilized Computational Fluid Dynamics (CFD) simulation tools to study ventilation efficiency and airflow dynamics, providing detailed wind velocity distributions and pressure fields to assist designers in optimizing building ventilation performance (Asfour et al., 2007) [26], much of the existing research has been case-specific, lacking generalized insights or direct comparisons across different building typologies. The challenge lies in quantitatively linking ventilation patterns with overall thermal comfort in a more comprehensive way.

Thermal comfort, a subjective measure of how satisfied a person feels within a thermal environment, is often assessed using models like the PMV-PPD index (Iwashita 1997) [27] or the Adaptive Comfort Model (ACM), which accounts for human adaptability to changing environmental conditions. The PMV-PPD thermal comfort model is extensively used to evaluate how indoor thermal environments affect occupants’ comfort. Research indicates that the combined effects of temperature, humidity, and airflow velocity influence subjective satisfaction with indoor environments. The Adaptive Comfort Model accounts for human physiological and behavioral adaptability, recognizing that people possess adaptive capabilities within certain temperature ranges. Consequently, this model is more suitable for assessing thermal comfort in naturally ventilated buildings (Xue et al., 2017) [28].

In recent years, an increasing number of studies have integrated natural ventilation with thermal comfort to comprehensively evaluate building indoor environmental quality, thereby aiding the design to better meet thermal comfort standards (Abdulraheem et al., 2025; Kocik et al., 2024) [29,30]. However, they do not fully account for the dynamic interactions between natural ventilation and thermal comfort in the context of traditional dwellings. While previous studies have made significant strides in assessing thermal comfort in naturally ventilated buildings, most focus on generic building types or single case studies, leaving a critical gap in comparative analyses of different traditional vernacular building variants. Our study seeks to bridge this gap by systematically evaluating the relationship between ventilation efficiency and thermal comfort across multiple traditional dwelling types in Kunming, offering insights into how spatial configurations and building scale influence indoor environmental quality.

2.3. Building Performance Simulation Method

In recent years, with the advancement of building performance simulation technologies, increasing research has begun to quantitatively analyze the climate adaptability of traditional buildings. Tools such as EnergyPlus 25.2.0, Autodesk CFD, or ENVI-met V5.7 are widely applied in studies examining the ventilation, daylighting, and thermal performance of traditional structures. In building performance simulation, EnergyPlus is a widely adopted energy efficiency modeling tool. It comprehensively evaluates thermal performance and energy consumption by simulating factors such as thermal conduction through building envelopes, indoor heat sources, and solar radiation. CFD simulation is widely applied to natural ventilation and airflow studies, providing reliable technical support for building ventilation design through detailed modeling of airflow paths, velocities, and pressure fields (Ramponi et al., 2012) [31]. Other advanced tools, such as ENVI-met, have been employed in parallel studies to simulate natural ventilation, thermal comfort, and thermal conduction through building envelopes, indoor heat sources, and solar radiation, offering comparative data that strengthens our understanding of these dwellings’ environmental adaptability.

Some scholars have employed these simulation tools to systematically evaluate the performance and adaptability of vernacular dwellings. EnergyPlus was used to simulate the energy consumption and comfort levels of traditional dwellings in northeastern Sichuan (Xia et al., 2024) [32] for integrating traditional architecture with modern sustainability goals. Similarly, recent studies have started validating the effectiveness of traditional farmhouse structures in Eastern Almería, Spain, under the typical high summer temperatures of the Mediterranean climate (Sáez-Pérez et al., 2024) [33]. A multifactorial analysis was conducted using ENVI-met software on representative examples of traditional courtyard-style architecture of the Yi ethnic group in southwestern Yunnan (Lin and Gui 2025) [34], and they clearly point out that the parameterized simulation and field verification framework have provided methodological reference for this study.

With the advancement of BIM (Building Information Modeling) technology, architectural design and evaluation increasingly rely on precise building performance simulation tools. Among these tools, platforms such as Rhino and Grasshopper, combined with plugins like Ladybug and Honeybee, have become essential instruments for building performance analysis [35,36]. These tools not only enable precise geometric modeling and meteorological data analysis, but also simulate building energy consumption, ventilation efficiency, and thermal comfort, providing designers with intuitive optimization solutions. This study will utilize these tools for natural ventilation simulation and thermal comfort analysis.

While these tools have been widely used in modern architecture, their application to traditional vernacular architecture has been limited. Most existing research applies these methods to contemporary buildings or isolated traditional structures without considering the full spectrum of variants within a given cultural and climatic context. This study aims to fill this gap by using these simulation tools to evaluate multiple traditional dwelling types in Kunming, offering a more comprehensive understanding of their performance across different climatic conditions and spatial configurations.

2.4. Impact of Climate Change on Buildings

The increasing frequency of extreme weather events caused by climate change will significantly affect the thermal performance and energy consumption of buildings. Research indicates that as global temperatures rise, longer hot periods may increase cooling demands, while milder winters could reduce heating requirements, creating challenges in terms of insulation and ventilation strategies (Martinez et al., 2025) [37]. Extreme weather events—such as bitter cold spells and severe storms—impose heightened demands on building envelope systems, ventilation systems, and shading facilities. The thermal insulation performance, natural ventilation potential, and shading measures of building envelope structures need to be re-evaluated to adapt to new climate conditions.

Optimizing the design of building envelopes and natural ventilation capabilities has become crucial for adapting to future climate conditions. Numerous studies indicate that passive design measures—such as natural ventilation and shading systems—employed in traditional buildings can effectively address potential future extreme climatic conditions (Zune et al., 2020) [38]. Studying the performance of traditional architecture in the current climate and predicting its adaptability in future climate scenarios is of great significance for developing adaptation strategies, preserving cultural heritage, and promoting sustainable building practices.

Most studies have focused on the energy implications of climate change in modern buildings, leaving a gap in understanding the vulnerability of traditional buildings in the face of such changes. Traditional buildings, designed for passive climate adaptation, may require reassessment of their insulation efficiency, natural ventilation potential, and shading capabilities to ensure their resilience under future climate conditions. This research aims to address these gaps by evaluating how traditional dwellings, such as those in Kunming, can adapt to the challenges posed by climate change, thereby contributing to the broader discourse on sustainable architecture and heritage preservation.

3. Methodology

3.1. Research Object Selection

As shown in Figure 9 and Figure 10, this study selected three representative vernacular dwellings in Haiyan Village, Kunming City—‘Half seal’, ‘One seal’, and ‘Two seals’—as research subjects. Through field surveys, precise measurements of dimensions, floor layouts, ceiling heights, wall thickness, and door/window positions and sizes were obtained. Using Rhino software, three-dimensional geometric models of these dwellings were constructed based on the measured data. Considering the complexity and accuracy requirements of simulation calculations, the models were simplified by omitting non-critical details (such as decorative elements) while retaining core features affecting ventilation and thermal performance, including building material, courtyards, room dimensions, spatial configurations, wall thickness, and window placement. Material properties were set according to typical values of conventional materials (such as bricks, wood, tiles, and ordinary window glass) referenced from relevant architectural physics manuals or databases.

3.2. Sources of Meteorological Data

The meteorological data used in this study are from the Typical Meteorological Year (TMY) dataset in EPW format, published on the official EnergyPlus Climate website by the U.S. Department of Energy (DOE). This dataset integrates representative hourly meteorological parameters from long-term observations, including dry-bulb temperature, wet-bulb temperature, relative humidity, wind speed, wind direction, and direct solar radiation intensity. It systematically and reliably reflects the typical characteristics of Kunming’s subtropical plateau monsoon climate, particularly its features such as small annual temperature variations, large daily temperature ranges, distinct dry–wet seasons, and intense solar radiation. Such standardized meteorological data are widely used in building energy consumption simulation, indoor/outdoor thermal environment assessment, and renewable energy system analysis, demonstrating high authority and applicability. These resources provide credible climatic boundary conditions and dynamic simulation inputs for this research.

3.3. Simulation Software and Parameter Setting

This study primarily utilizes Rhino and its plugins for simulation analysis: (1) Ladybug Tools are used to load and process typical annual meteorological data from the Kunming region in TMY. For the natural ventilation simulation, wind speed and wind direction data are standardized based on the TMY dataset for Kunming. This dataset includes seasonal variations in wind speed and direction, and these data are used in the simulation to define the wind speed profile. (2) Honeybee, as the core plugin, it is used to establish building performance simulation models, set simulation parameters, and invoke the background computing engine.

Simulation parameters included indoor heat sources from occupants and equipment, initial indoor temperature assumed to match outdoor conditions, simulation grid division configured according to default software settings or empirical parameters to ensure accuracy, and the time step. All simulations were conducted under identical climatic data, indoor conditions, and boundary settings to ensure the comparability of the results.

The simulated input winter and summer wind speed values are 2.7 m/s and 2.9 m/s, and southern winds prevail in both seasons. The wind speed profile reflects the typical climate conditions of the area to ensure that the simulation results realistically represent the local climate environment. The assessment of thermal comfort used the ASHRAE 55 adaptive comfort model, which adjusts comfort thresholds based on seasonal changes and the occupants’ ability to adapt to environmental variations. According to ASHRAE 55, the acceptable PMV range for indoor thermal comfort is between −0.5 and +0.5. In this study, PMV values were calculated at different indoor locations, with the indoor temperature target range set at 25–28 °C in summer and 16–20 °C in winter. Clothing levels were adjusted according to the season, with lighter clothing in summer (0.5 clo) and heavier clothing in winter (1.0 clo).

3.4. Data Validation

To ensure the reliability of simulation results, this study conducted on-site monitoring at the Yikeyin dwellings in Haiyan Village during a typical summer period, specifically 18–24 August 2023. This 7-day continuous monitoring was strategically selected to fully capture the seasonal climate characteristics of the study area and reflect real-world usage scenarios of the vernacular dwellings.

For data acquisition, four HOBO MX2301A (made by ONSET, Cape Cod, MA, USA) temperature and humidity loggers and four Testo 405i (made by Testo AG, the Black Forest region, Lenzkirch, Germany) anemometers were deployed. The instruments were positioned across key spatial units of the residential complex, including the courtyard, principal room, gatehouse, and side room—this layout was designed to ensure the representativeness of monitoring data, covering both indoor and outdoor microclimate parameters (temperature, humidity, and wind speed). The sampling frequency was standardized at once every 10 min.

Subsequently, the measured outdoor microclimate data were input as boundary conditions into the simulation model, followed by a comparative analysis between simulated and on-site measured values. The results indicated that the root mean square error (RMSE) between simulated and measured indoor temperatures was 0.8 °C, with a mean absolute error (MAE) of 0.6 °C. Notably, both sets of temperature trends showed high consistency (as illustrated in Figure 11), validating the model’s accuracy in thermal environment simulation and providing reliable data for subsequent analyses.

4. Results and Analysis

4.1. Summer

4.1.1. Natural Ventilation in Summer

Summer simulation results demonstrate that building volume and spatial configuration significantly influence natural ventilation efficiency. As shown in Figure 12, the ventilation performance of the ‘Half seal’ dwelling consistently achieves the highest ventilation efficiency, with an average air change rate of 3.8 times/h, and a peak of 4.5 times/h. The ‘Half seal’ design, featuring compact courtyard dimensions, high atrium openness, and a large window-to-wall ratio, creates an efficient through-draft channel. This configuration achieves the highest average air change rate among the three courtyard types. Its airflow distribution is exceptionally uniform, while virtually eliminating ventilation dead zones. Particularly near windows and doors, ventilation performance remains optimal. Most areas experience rapid air renewal throughout most time periods.

The ‘One seal’ dwelling shows intermediate ventilation efficiency between ‘Half seal’ and ‘Two seals’. The average ACH is 2.2 times/h, and the ACH for the north side of the secondary bedroom drops to 1.5 times/h, resulting in airflow stagnation areas. While its atrium’s wind-guiding and exhaust functions outperform large-scale buildings, increased room numbers and expanded volume in comparison to ‘Half seal’ may create ventilation dead zones in some interior spaces, resulting in slightly lower ACH and airflow stagnation in deep areas. The optimization of window alignment and atrium dimensions could further enhance ventilation.

Simulation results indicate that ‘Two seals’ exhibits the lowest overall ventilation efficiency, which leads to significant airflow stagnation, especially in the interior spaces and transition areas. The average ACH is only 1.1 times/h, and the ACH in the transition zone and deep room is less than 0.8 times/h. Enlarged building volume and complex internal layouts cause extended airflow paths with multiple turns, significantly reducing ACH. Potential ventilation dead zones emerge, particularly in transitional areas connecting deeper interior spaces, where the ventilation problem is prominent.

4.1.2. Indoor Thermal Comfort in Summer

Figure 13 demonstrates that the ‘Half seal’ dwelling consistently remains in the comfortable PMV range, while the ‘One seal’ and ‘Two seals’ dwellings experience higher PMV values, especially in areas with reduced ventilation, leading to some discomfort. The PMV values for the ‘Half seal’ dwelling in summer remain within the cool-to-neutral zone, indicating excellent thermal comfort performance with minimal overheating risk. The ‘Half seal’ design, with its high air change rate, effectively suppresses heat accumulation. The PMV value remains stable between −0.3 and +0.2 during summer, with an average PPD of just 12%, showing that 88% of the time it is within the thermal comfort zone. Evaluation results based on the ASHRAE 55 Adaptation Model indicate a strong positive correlation between indoor thermal comfort performance and ventilation efficiency in summer [39].

The ‘One seal’ dwelling demonstrates good overall thermal comfort due to atrium shading and moderate ventilation, though poorly ventilated edge spaces may experience elevated PMV readings and moderate localized overheating risks. The PMV of ‘One seal’ dwellings is predominantly distributed between −0.2 and +0.4. In localized overheating zones (e.g., west-facing side rooms), the PMV rises to +0.4, corresponding to a 18% PPD and an 82% comfortable period. The ‘Two seals’ dwelling suffers from inadequate ventilation causing slow heat dissipation, maintaining PMV values in prolonged warm ranges at +0.3~+0.4 for a long time, with an average PPD of 35%. During the afternoon hours from 13:00 to 16:00, the PPD exceeds 40%. Its PPD significantly exceeds other courtyard types, resulting in the highest overheating risk and poorest thermal comfort.

4.2. Winter

4.2.1. Natural Ventilation in Winter

Due to low wind speeds in winter, the ACH of all three types of dwellings decreased compared to in the summer. However, the relationship between ventilation and heat retention becomes more pronounced when considering building volume and enclosure structure configurations. As shown in Figure 14, the ‘Half seal’ dwellings maintain high ACH levels of 1.9 times/h. Due to the large opening area, cold air infiltration causes indoor temperature fluctuations of up to 5.2 °C. The ‘One seal’ dwelling ACH averages 1.3 times/h, with temperature fluctuations controlled at 3.1 °C, achieving a balance between ventilation and thermal insulation. Although the ‘Two seals’ dwelling demonstrates the lowest winter ventilation efficiency, with an average ACH of only 0.7 times/h, leading to less airflow and potentially higher indoor humidity levels, the low ventilation rate reduces heat loss and minimizes temperature fluctuations to only 1.8 °C.

4.2.2. Indoor Thermal Comfort in Winter

The chart in Figure 15 highlights the differences in thermal comfort across dwelling types in winter. Thermal comfort simulations indicate that winter performance primarily depends on a building’s thermal inertia and solar utilization capacity. The ‘Half seal’ dwelling, with rapid temperature drops at night, shows PMV values in the cooler range, indicating discomfort. The ‘Half seal’ design, with its low thermal inertia, experiences rapid nighttime or sunless temperature drops, resulting in PMV typically ranges from −0.8 to −0.4, with an average PPD of 22% and high subcooling risks. However, direct sunlight through skylights during the daytime can temporarily improve thermal comfort.

The ‘One seal’ configuration, leveraging moderate dimensions and wall thermal capacity, maintains stable indoor temperatures with minimal fluctuations, meaning that PMV remains stable between −0.6 and −0.2, with an average PPD of 15% and 75% comfort periods. The ground floor of the principle room shows the best thermal comfort, while the PMV shows a slight coolness. The ‘Two seals’ dwellings, characterized by large scale and high thermal inertia, maintain better temperature stability but may still fall below comfort thresholds under prolonged cloudy conditions. Due to its high thermal inertia, the PMV remains between −0.5 and −0.1, with a PPD of just 12%. However, on cloudy days without sunlight, the PMV in some poorly lit rooms may drop to −0.7, while the PPD rises to 18%.

4.3. Comprehensive Comparison

Based on the simulation results of natural ventilation and indoor thermal comfort in both summer and winter, the three courtyard types demonstrate distinct performance characteristics. The ‘Half seal’ type shows superior ventilation efficiency and thermal comfort in summer, achieving the highest average ACH and comfort zone coverage while maintaining the lowest overheating risk. However, its low thermal inertia and large opening areas lead to significant heat loss in winter, causing rapid temperature drops at night and during cloudy periods, with markedly reduced thermal comfort. The ‘One seal’ type balances performance across seasons, in summer, ventilation through courtyards and shading prevent heat accumulation, while in winter, heat retention is maintained by moderate scale and enclosed exterior layouts. The ‘Two seals’ dwelling type, characterized by its massive size and complex internal spaces, exhibits the lowest summer ventilation efficiency and heat retention capacity, with highest overheating risk. Winter performance is enhanced by high thermal inertia that minimizes temperature fluctuations and reduces supercooling risks. Nevertheless, some sun-deprived areas may still experience overall cooling under overcast conditions.

From Figure 16 and Figure 17, it can be seen that the average ACH for ‘Half seal’, ‘One seal’, and ‘Two seals’ dwellings are 3.8 times/h, 2.9 times/h, and 1.6 times/h in summer, while in winter, they are 2.5 times/h, 1.8 times/h, and 0.9 times/h. The daily temperature fluctuations in summer for ‘Half seal’, ‘One seal’, and ‘Two seals’ dwellings are 3.5 °C, 2.6 °C, and 1.7 °C, while in winter, they are 6.2 °C, 3.5 °C, and 2.1 °C. The mean summer PPD for ‘Half seal’, ’One seal’, and ‘Two seals’ dwellings is 12%, 18%, and 35%, while the mean winter PPD is 22%, 15%, and 12%.

Table 1. Quantitative comparison of the core performance of three types of traditional courtyard dwellings in summer and winter.

Types of Yikeyin	ACH in Summer (Times/h)	Summer PMV	ACH in Winter (Times/h)	Winter PMV
Half seal	3.8~4.5	−0.3~+0.2	1.9~2.6	−0.8~−0.4
One seal	1.5~2.9	−0.2~+0.4	1.3~1.8	−0.6~−0.2
Two seals	0.8~1.6	+0.3~+0.4	0.7~1.0	−0.5~−0.1

further summarizes key performance characteristics of the three courtyard types, providing a reference for quantitatively comparing their advantages and shortcomings in seasonal microclimate adaptability. As shown in Table 1, the summer ACH values for ‘Half seal’, ‘One seal’, and ‘Two seals’ dwellings are 3.8~4.5, 1.5~2.9, and 0.8~1.6, while the winter PMV values are 1.9~2.6, 1.3~1.8, and 0.7~1.0. The fluctuation range of PMV in summer for ‘Half seal’, ‘One seal’, and ‘Two seals’ dwellings is −0.3~+0.2, −0.2~+0.4, and +0.3~+0.4, while in winter, they are −0.8~−0.4, −0.6~−0.2, and −0.5~−0.1.

The radar chart (Figure 18) presents comprehensive evaluations of the three courtyard types across four dimensions: summer ventilation efficiency, summer thermal comfort, winter ventilation efficiency, and winter thermal comfort, with qualitative explanations provided for each indicator in Table 1. It uses a 1–5 point scale for quantitative scoring (1 = worst, 5 = best), with scores based on the core performance indicators in Table 1. The chart visually demonstrates performance differences among the courtyard types. Among them, the ‘Half seal’ type demonstrates the best ventilation and thermal comfort in summer, but poorer thermal comfort in winter, the ‘One seal’ type exhibits good ventilation and thermal comfort throughout the year, and the ‘Two seals’ type achieves the best thermal comfort in winter but has low ventilation efficiency, resulting in the worst thermal comfort and ventilation in summer.

The analysis shows that building size and spatial organization have a significant impact on natural ventilation efficiency and thermal comfort. Smaller volume and more open spatial layout are conducive to the formation of effective through-air, while large and complex buildings are more prone to poor ventilation areas.

(a) From the comparison of natural ventilation efficiency in summer, the ‘Half seal’ dwelling has the highest ventilation efficiency, while the ‘Two seals’ dwelling has the lowest. The overall ventilation efficiency decreased in winter, but the trend was consistent with that in summer.

(b) Summer thermal comfort comparison shows that the PPD values of the ‘Two seals’ dwelling type were significantly higher than those of the other two dwelling types, indicating the highest risk of overheating in summer. On the contrary, the ‘Half seal’ dwelling type has the highest PPD in winter, while the ‘Two seals’ dwelling type has the lowest PPD.

(c) According to the comparison of the range of daily temperature fluctuation, the diurnal temperature range of the ‘Two seals’ dwelling type is the most stable, while that of the ‘Half seal’ dwelling type fluctuates the most across the year.

From the perspective of adaptive strategies, building volume, spatial layout, and courtyard morphology are core factors influencing natural ventilation and thermal comfort. Smaller volumes with high openness facilitate summer ventilation and heat dissipation, while larger volumes with high thermal inertia help maintain winter insulation and temperature stability. This finding indicates that traditional courtyard designs have evolved over time to achieve adaptive balance with local climate conditions. However, when addressing future climate changes, performance differences across types require targeted optimizations tailored to seasonal needs. For instance, introducing enhanced ventilation measures in ‘Two seals’ designs, or improving winter insulation in ‘Half seal’ configurations, can collectively enhance annual comprehensive thermal comfort.

5. Discussion

5.1. Climate Adaptability and Limitations of Traditional Dwellings

This study quantitatively demonstrates that Yikeyin in Haiyan Village contains effective strategies to cope with Kunming’s climate. For instance, the central courtyard not only provides natural lighting and partial heat gain but, more importantly, facilitates natural ventilation. The rational layout of doors and windows also reflects the utilization of prevailing wind directions and solar pathways. Under current climatic conditions, these strategies enable traditional vernacular dwellings to maintain acceptable thermal comfort for most of the year, embodying the sustainability inherent in traditional architecture. However, the research also reveals limitations. As building scale increases (from ‘Half seal’ to ‘Two seals’), ventilation efficiency significantly decreases, while summer overheating risks rise.

This study uses IPCC SSP2−4.5 climate scenarios to assess the potential impact of future climate change on building performance. In this situation, future temperature increases are expected to increase the risk of overheating in certain building types. For example, the ‘One seal’ dwelling retains 68% comfortable hours (10% reduction), while the summer overheating days of the ‘Two seals’ dwelling may drop the comfortable hours to 45% (30% reduction), highlighting the necessity of adaptive design to adapt to future climate change, and proving that moderate-scale dwellings have stronger climate resilience. This suggests that simply replicating or expanding traditional architectural forms may not preserve their original climate-adaptive advantages. Additionally, although traditional dwellings’ enclosure materials, such as brick walls, possess certain thermal inertia, their insulation performance may prove insufficient when facing potentially more extreme high-temperature scenarios in the future, especially without access to modern insulation materials and technologies.

5.2. Adaptation Potential Assessment in the Context of Climate Change

By integrating climate change projections (e.g., temperature increases in Kunming as predicted in IPCC reports or regional climate models), we can preliminarily evaluate the adaptive potential of these three traditional dwellings. The excellent ventilation performance of the ‘Half seal’ dwelling may still offer some advantage in coping with higher summer temperatures, but insufficient winter insulation could become more prominent. The relatively balanced performance of the ‘One seal’ dwelling might maintain adaptability under future climates, though both summer overheating and winter insulation issues could worsen, potentially requiring additional shading, enhanced ventilation, or localized insulation measures. In increasingly hot climates, poor ventilation and summer overheating of ‘Two seals’ dwellings would likely intensify, necessitating fundamental renovations such as adding mechanical ventilation, reinforcing shading systems, or altering spatial layouts to improve airflow organization. This demonstrates that traditional buildings’ climate adaptability is not static, and it requires ongoing assessment and adjustment according to evolving climate realities. The wisdom embedded in these designs, like utilizing courtyard ventilation and rational spatial arrangements, can inspire future architectural innovations, though specific forms and constructions must advance with the times.

5.3. Practical Significance and Implications of the Study

The findings of this research carry significant practical implications:

(1) This study provides scientific evidence for preserving and restoring the ‘Yikeyin’ series of residential buildings in Haiyan Village. Cultural heritage conservation and restoration should not merely focus on superficial restoration but prioritize functional enhancement. For instance, optimizing window and door openings while maintaining traditional esthetics can improve ventilation efficiency, and applying modern insulation treatments to walls may enhance thermal comfort during winter.

(2) Traditional dwellings’ climate-adaptive strategies, such as compact layouts, courtyard utilization, and passive ventilation systems, offer valuable references for contemporary sustainable architecture, particularly for buildings in similar climate zones. Designers can draw inspiration from these spatial organization principles, integrating modern materials and construction techniques to create sustainable structures that harmonize with regional culture while adapting to climate conditions. The core of the traditional Yikeyin lies in its courtyard, whose spatial prototype can be transformed into a vertically oriented climate buffer atrium. The systems dynamically respond to climate data to maximize energy efficiency.

Drawing from the courtyard principle of the ‘One seal’ dwelling type, the atrium functions as a solar chimney. By expelling hot air, it drives natural ventilation in lower levels, reducing air conditioning energy consumption. Through adjustable shading and high thermal inertia materials, it absorbs or releases energy to stabilize internal temperature and humidity fluctuations. The ‘Half seal’ design, with its smaller volume and open space, achieves the highest ventilation efficiency. Drawing from the compact form, layouts with reduced depth, dual corridors, or offset cores create direct exterior access for most spaces, leveraging through-drafts to enhance natural ventilation efficiency. Horizontal ventilation pathways evolve into vertical ducts. Computer simulations precisely control openings to channel prevailing winds through the building, ventilating interior spaces and eliminating ventilation dead zones in high-rise structures. The ‘Two seals’ design maintains stable indoor temperatures in winter due to its large volume and high thermal inertia. High-performance insulation using phase-change materials, combined with intelligent building envelopes, efficiently controls indoor temperature fluctuations.

(3) The research highlights the need to address summer overheating in both traditional and modern buildings under climate change scenarios. Designers should prioritize passive strategies like optimizing building orientation, maximizing natural ventilation potential, and implementing efficient shading measures. For large-scale structures, particular attention should be paid to ventilating internal spaces.

5.4. Aligning with Existing Policy

Research reveals performance disparities among different residential types, translating into localized technical guidelines for energy-efficient retrofits of traditional dwellings. These provide ventilation enhancement solutions and thermal insulation optimization recommendations for local courtyard-style buildings, supporting the precise implementation of ‘Dual Carbon Goals’ within traditional neighborhood renewal.

Research also indicates that risks of summer overheating and winter overcooling directly impact residents’ quality of life. When implementing rural housing renovation subsidies, shifting from esthetic subsidies to performance subsidies is recommended. This approach strengthens human settlements in rural revitalization objectives based on achieved performance metrics, such as ventilation efficiency and indoor thermal comfort after renovations. It encourages residents to voluntarily preserve and enhance the climate-adaptive design features of traditional courtyard houses during self-initiated renovations. This strategy improves livelihoods while effectively preserving regional ecological wisdom.

5.5. Limitations of the Study

Although this study provides a systematic quantitative assessment of the climate adaptability of the ‘One seal’ traditional dwellings in Haiyan Village, Kunming, several limitations remain and should be addressed in future research.

(1) Model simplification and boundary assumptions.

To ensure computational feasibility and comparability, the simulation models were simplified by omitting detailed architectural elements (e.g., decorative eaves, lattice windows) and assuming that each building was situated in an open, unobstructed environment. While this approach isolates the physical effects of form and spatial organization, it does not fully account for settlement density, mutual shading, or topographic influences, which may cause deviations from real-world microclimate conditions.

(2) Uncertainty of meteorological data and climate scenarios.

The study relied on the Typical Meteorological Year (TMY3) dataset for Kunming, which represents general climate conditions but excludes extreme events. Future climate adaptability was inferred from IPCC-projected temperature trends rather than regional climate models (RCMs), thus offering indicative rather than predictive conclusions.

(3) Applicability of the thermal comfort model.

The ASHRAE 55 Adaptive Comfort Model, derived mainly from Western population data, may not fully reflect the physiological and behavioral adaptation of local highland residents. Moreover, occupant behaviors—such as window operation, activity patterns, and adaptive habits—were not dynamically modeled, potentially affecting ventilation and comfort evaluations.

(4) Material parameters and field validation.

Although limited on-site measurements validated the summer simulations, the sample size and monitoring duration were restricted. Thermal properties of adobe and timber were obtained from references rather than in situ testing, potentially leading to discrepancies due to material aging and moisture variability.

(5) Sample diversity and typological scope.

The three dwelling types—‘Half seal’, ‘One seal’, and ‘Two seals’—represent key typologies but cannot encompass the full diversity of courtyard dwellings in the Dianchi Lake region. Broader surveys covering various orientations, combinations, and historical phases would improve representativeness.

(6) Future research directions.

Future work should (i) integrate the building models into settlement-scale CFD or ENVI-met simulations to evaluate coupled wind and thermal environments; (ii) employ dynamic climate scenarios (e.g., RCP4.5, SSP2–4.5) to assess adaptive thresholds under different warming conditions; (iii) incorporate local behavioral data to calibrate region-specific comfort models; and (iv) explore hybrid strategies combining vernacular passive wisdom with modern green technologies to support sustainable conservation and renewal of traditional dwellings in plateau regions.

6. Conclusions and Prospects

This study evaluated the climate adaptability of three variants of Yikeyin dwelling, ‘Half seal’, ‘One seal’, and ‘Two seals’, in Kunming via field monitoring, meteorological simulation, and statistical validation, with key findings supported by quantified data. Under current climates, ‘Half seal’ dwellings excel in summer (ACH = 3.8~4.5 times/h, PMV = −0.3~+0.2, PPD = 12%) but lack winter stability and thermal comfort (Diurnal temperature fluctuation = 6.2 °C, PMV = −0.8~−0.4). ‘Two seals’ perform well in winter (Diurnal temperature fluctuation = 2.1 °C, PMV = −0.5~−0.1, PPD = 12%) but suffer summer overheating (ACH = 0.8~1.1 times/h, PPD = 35%). ‘One seal’ achieves an optimal balance, with summer ACH = 1.5~2.9 times/h, PMV = −0.2~−0.4, PPD= 18%, winter diurnal temperature fluctuation = 3.5 °C, and PPD= 15%, confirming its suitability for Kunming’s plateau climate.

As the predominant typology in the area (35%), the ’One seal‘, with its ’middle course’ design philosophy, achieves an optimal balance in overall annual performance, reflecting a high degree of climate-adaptive intelligence. This study not only addresses the gap in the quantitative assessment of climate adaptability in vernacular dwellings but also provides critical data support and a theoretical basis for the scientific preservation, adaptive renewal, and sustainable inheritance of vernacular architecture in the context of climate change.

This study’s simulation analysis is grounded in a critical premise, which the residential buildings under investigation are situated within open spaces, disregarding potential obstructions and wind field interference from neighboring structures. This simplified approach allows for a focused examination of how architectural form, scale, and spatial configuration fundamentally influence indoor microclimate dynamics, enabling a direct comparison of three Yikeyin variants. However, it should be noted that in actual village settlements, high building density creates mutual shading effects between adjacent dwellings. These interactions may affect simulation results through two mechanisms: (1) Wind environment modification: Adjacent buildings alter local wind pressure distribution, potentially obstructing or redirecting prevailing winds, which significantly impacts ventilation efficiency at building openings. Areas previously well-ventilated in open spaces could become dead zones due to wind shadow effects under dense layouts. (2) Solar heat reduction: Shading from surrounding buildings decreases solar radiation received by exterior walls and courtyards. While this may reduce thermal load and overheating in summer, it diminishes beneficial solar heating in winter, potentially exacerbating indoor coldness.

Therefore, the conclusions drawn in this study under open-field assumptions, particularly the quantitative findings regarding optimal ventilation in ‘Half seal’ configurations and the highest summer overheating risks in ‘Two seals’ configurations—should be approached with caution when applied to actual high-density settlements. The simulation results should be interpreted as revealing three inherent physical characteristics of architectural forms, rather than representing their absolute performance in real-world built environments.

Future research could integrate the monomer model established in this study into a comprehensive settlement model based on authentic village layouts for simulation. Through CFD simulations of wind environments across entire areas and analysis of solar radiation under mutual shading conditions, we can more accurately evaluate the climate adaptability of traditional dwellings in real-world complex built environments. This will advance research findings from theoretical guidance to direct support for practical conservation and renewal initiatives. The study reveals the potential value and challenges of traditional architecture in addressing climate change, emphasizing the importance of scientific assessment and creative adaptation of traditional wisdom. We hope this research contributes to sustainable development in the architectural field.