A research group led by the Singapore University of Technology and Design found nearly half of 416 HDB flats it visited across 10 neighbourhoods were warmer indoors than outdoors, with poor or blocked airflow a key reason. [1]
The team surveyed more than 1,000 residents during nine months of home visits that began in October 2024. It found close to 60% of homes had lower airflow than outdoors. [1]
Around one-third of households were up to 2C warmer than their immediate void decks, and about 10% were up to 5C hotter than outdoors. In one home, researchers recorded a heat index of 35.9C indoors versus 31.1C outside. The largest cited temperature gap was 36.2C indoors and 27.8C outdoors. [1]
Dr Harvey Neo said: “We found that higher levels of indoor clutter and keeping windows closed for long periods were associated with warmer homes and poorer ventilation. When airflow pathways are blocked, heat accumulates indoors and is slow to dissipate.” [1]
The homes studied included those occupied by elderly residents and lower-income families, groups the researchers said were disproportionately affected by the heat. [1] The study also said many residents had normalised indoor heat despite possible health risks, especially for seniors whose ability to regulate body temperature declines with age. [1]
The researchers said future policy should focus on co-funding effective cooling and housing design improvements. [1]
