Retrofitting Existing Residential Buildings for Energy-Efficient Indoor Cooling in Tropical Climates: A Framework for Affordable Climate Adaptation

Abstract

For buildings already built in a tropical climate, rising cooling demand and temperatures are leading to thermal challenges. Many home dwellings are poorly protected from direct heat from the sun and are unable to cool themselves sufficiently, making them more likely to rely on fans and air-conditioning. In this research, the empirical evidences concerning retrofit measures to enhance the indoor cooling conditions, reduce cooling-energy demand and improve the climate adaptation of the existing residential buildings in tropical climates were reviewed. The literature search was done systematically following the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA 2020) guidelines. Literature searches were conducted in major academic search databases and included citation searching, and a specific search using African data. Context such as climatic conditions, retrofit measure, thermal outcomes, energy performance, affordability and climate adaptation value were assessed for the studies that were eligible. The 12 empirical studies that were used for the core synthesis were comprised of nine studies conducted in African countries and three studies conducted in Asian countries. The results indicated that reflective roofs consistently reduced the indoor heat, with the cool roof treatments and external roof covers also showing a beneficial effect, depending on building and climatic conditions, whereas shading, insulation and suitable ventilation also gave further benefits. There were also some retrofit packages that showed potential for saving energy and improving indoor conditions that cost less. The effectiveness of ventilation was less consistent, however, and passive ventilation methods were less effective under some future climate scenarios. Based on these results, an affordable climate responsive retrofit framework was developed for building assessment, heat sources identification, prioritisation of interventions, selection of affordable retrofit packages, assessment of renovation performance and evaluation of climate-resilience. The framework is an evidence-based process to enhance current residential buildings, whilst taking into consideration household resources and changing climatic conditions.