Tropical weather is characterized by high humidity, high temperature, and intense solar insolation; therefore, traditional tropical housing is predominantly dependent on natural ventilation and passive cooling for thermal comfort. In the literature and practice, however, there is a gap of knowledge on Myanmar vernacular housing, specifically with regard to the variation in weather caused by climate change. In this paper, the authors review passive design techniques used in Myanmar vernacular houses to achieve thermal comfort. Using an experimental design approach, simulation studies were carried out to compare the impact of various passive design techniques on thermal comfort in three Myanmar climates. Different passive design techniques used in the two houses were further reviewed. Fifteen models were generated through an evaluation of the latter to examine the thermal performance of Myanmar housing throughout a year, with typical weather and predicted future climate scenarios. The results revealed that the efficacy of traditional passive design techniques would not be sufficient to achieve thermal comfort in the predicted future climate scenario. For this reason, the authors suggested that the passive design techniques of Myanmar vernacular housing need to be improved, with innovative solutions in order to cope with the changing climate.

The integration of vernacular strategies in Myanmar housing seems to have remained remarkably resilient and is still the norm even in modern dwellings. However, no regard is given to the possible impact of climate change.Using one-year monitored indoor and outdoor thermal environment data, typical and a morphed weather data representing future climate change scenarios, the authors investigated whether modern dwellings in Myanmar can provide thermal comfort in the present and future, and measured how vulnerable to overheating risks they are. Building envelope materials based on typical construction found locally and window shading were varied in the simulations, in order to understand their role in the resultant building performance.The analysis showed that the number of hours above 30°C in 2019 doubled when compared to a typical weather year. This study contributes valuable insights into how the combined effect of air temperature and humidity will affect building thermal performance in future climate scenarios. Temperature readings reaching the 'danger' heat index threshold were 14.06% of the time in 2019 and only 5.49% in the typical weather year. This indicated that modern dwellings in Myanmar are facing two challenges: high vulnerability to extreme heatwave events, and inadequate response to increased mean air temperatures.

Myanmar's territory mostly experiences tropical monsoon climate, where temperatures are normally not extreme, but humidity can increase discomfort. In response, vernacular architecture strategies have evolved to deal with excess heat and humidity. One of the most prominent of these strategies is the use of high multistage roofs with ventilation. Over the years, many of the traditional buildings were altered but the use of multistage roof design has remained remarkably resilient in Myanmar. Nevertheless, little is known about their contribution to thermal comfort and their vulnerability to overheating risks due to the pervasive threat of the climate crisis.In the work presented here, a thorough review of multistage roof typologies was followed by an investigation of their performance when building parameters including form, ventilation and materials were varied. Twenty-four dynamic simulations were performed using three building typologies and thirty-two fluid dynamic simulations were performed using two building typologies. In all cases, indoor volumes were kept the same. The results suggest that with the use of typical light-weight permeable envelope, the indoor temperatures follow ambient temperature closely; although a heavier-weight set of materials did not impact significantly on the maximum air temperatures, it has made a different with regard to the lowest temperatures and overall comfort. The variable that impacted the most on the results was roof ventilation mode, with the best results being 3.5% of a year better than the worst. The multistage roof was found to help reduce heat gains form solar radiation.The findings showed that Myanmar's vernacular buildings with multistage roofs offer an opportunity to improve indoor comfort in tropical climates and therefore its ability to moderate indoor temperatures through the use of simple building physics and geometry should be honoured.

In Brazil, the delivery of homes for low-inc ome households is dictated by costs rather than performance. Issues such as the impact of climate change, affordability of operational energy use, and lack of energy security are not taken into account, even though they can severely impact the occupants. In this work, the authors evaluated the thermal performance of two affordable houses as-built and after the integration of envelope improvements. A new replicable method to evaluate the cost-effectiveness of these improvements was proposed. The case study houses comprise the most common affordable housing type delivered widely across Brazil and a proposition of a better affordable housing solution, built in Porto Alegre, southern Brazil, integrating passive design strategies to increase thermal comfort. The findings reveal a potential for improving indoor thermal conditions by up to 76% and 73%, respectively, if costs are not a concern, and 40% and 45% with a cost increase of 12% and 9% if a comfort criterion of 20–25 °C was considered. Equations to estimate costs of improvements in affordable housing were developed. The authors concluded that there is a great scope for building envelope optimisation, and that this is still possible without significant impact on budget.

No abstract