Improving indoor environmental quality in an affordable house by using a vegetated wall: A case study in subtropical Brazil

Abstract

Indoor environmental quality of buildings, including thermal, acoustic, visual comfort, and air quality, directly impacts the comfort, health, and productivity of occupants. However, in Brazil, the high deficit of affordable housing units has led to a situation where environmental quality is often overlooked in favour of low investment costs, prioritizing quantity over quality. Furthermore, the poorest segments of the population, who rely on affordable housing, are disproportionately affected by energy costs. Therefore, it is crucial to conduct research on low-cost energy solutions for social housing to improve the sustainability of people's lives. In this light, a study was conducted to monitor the energy performance of a vegetated wall made of deciduous species and compare it to a bare wall used in an affordable house in subtropical Brazil. Parameters, such as internal and external surface temperatures, nearby microclimatic conditions, and heat transfer through the vegetated and bare walls, were monitored every 5 min over a two-year period. The heat flux analysis revealed that the vegetated wall reduced conductive heat up to 83 % during summer days, significantly lowering the external surface temperature by 8.6 °C due to the presence of the plant layer. Moreover, the vegetated wall generally exhibited lower shortwave and longwave radiative and convective heat fluxes. These findings contribute to our understanding of energy transfer through vegetated walls in subtropical Brazil, including the impact of adjacent microclimatic conditions. Furthermore, the results confirm the potential of vegetated walls to effectively reduce cooling and heating demands at a minimal additional cost.