Heatwave driving you up the wall? 7 ways to cool your home without increasing your electricity bill

SINGAPORE – Retreating indoors seems like an obvious escape from Singapore’s relentless mid-year heatwave.

Yet, there is a chance that the air inside your home is actually warmer than the air outside.

A recent study led by the Singapore University of Technology and Design (SUTD) found that nearly half of more than 400 Housing Board flats were warmer than the outdoors.

Around one-third of these flats were up to 2 deg C warmer than their void decks. The hottest 10 per cent of the homes experienced indoor temperatures up to 5 deg C hotter.

This was mostly due to poor airflow within the 416 households visited by researchers in late 2024. 

In fact, almost 60 per cent of these flats had lower airflow than the outdoors, as they were stifled by clutter, closed windows and home layouts that were not conducive to cooling. 

The Straits Times highlights seven ways to optimise airflow and cool your home – all while keeping costs down during the global energy crisis. 

Open windows and doors

Modern life is replete with heat-emitting appliances, from refrigerators to computers. These release heat that can accumulate and raise the indoor temperature, unless it can escape outdoors.  

Dr Zheng Kai, a lecturer in the architecture and sustainable design pillar at SUTD, tells ST: “Our studies have found that many households leave their windows closed, so there is barely any natural ventilation in the home.” 

Dr Zheng is one of the researchers involved in the multi-institute study.

Multiple openings – for instance, a main door on one side of a room and a window on the opposite side – will enable cross-ventilation. Air will flow from one opening to another, and create a passive breeze along the way. Given that outdoor wind always changes direction, it is best to leave as many windows open as possible to maximise cross-ventilation.

Remove clutter

“Declutter and reduce bulky furniture pieces within the home to allow better air movement,” suggests Ms Priscilla Tan, founder of design firm StyledbyPT.

“Consider elevating heavy items such as beds and sofas with furniture risers to allow air to circulate underneath.” 

Keep loose items in cabinets and avoid placing tall furniture, such as privacy screens, near windows or main entrances. This helps to clear the breeze path between openings.

Dr Zheng says: “Occupants can do a simple approximation of the breeze path by identifying the direct line between two open windows.”  

Position fans strategically

By itself, a ceiling, standing or wall-mounted fan does not reduce temperature. Instead, it generates airflow that moves heat away from the body. Higher speeds create greater airflow and, therefore, a more significant cooling effect. 

“Ceiling fans are one of the most effective low-energy solutions and should be positioned centrally in living and sleeping areas,” says Ms Tan. 

When they are installed, ensure there is enough head room for air to be pulled down from the top of the room.

Standing fans can also be positioned according to usage. 

“To remove the heat from your unit, point the fan out towards the window, so the warm air in the home can be blown outwards,” says Dr Zheng. 

Use blinds, curtains and solar films 

Opening windows and doors will let wind move in and out of a home. But it also means inviting dust, insects, harsh sunlight and potentially prying eyes.

“If privacy or direct sunlight is a concern, consider installing Venetian blinds so that the window is still partially exposed and wind can flow through,” suggests Dr Zheng.

Ms Tan recommends sheer curtains in breathable, light-filtering fabrics like linen or cotton. 

Home owners can also consider installing solar film on windows that directly face the sun. This will reduce the heat gain in the space. 

“Just be aware that many ‘solar films’ in the market reduce visibility, but don’t reduce heat,” notes Dr Zheng. 

Add air coolers and misting systems

Misting fans and coolers rely on evaporative cooling. When water turns into vapour, it absorbs heat from the air, instantly lowering the surrounding temperature.

“These evaporative coolers do not emit heat like traditional air-conditioners, other than the waste heat from fans, which is relatively insignificant,” says Dr Zheng.

It is best to use these misting fans and coolers in open spaces, so humidity does not build up.

Evaporative coolers can be very effective during hot afternoons, when Singapore’s relative humidity usually drops from an average of 80 to 90 per cent to 50 to 60 per cent. But they work less well at night, when the relative humidity is higher. 

Plants also lower the temperature through evaporative cooling. 

“But a large area of green is needed to have any significant change in temperatures, so it’s not quite possible in a typical household,” Dr Zheng says.

In fact, plants may even impede airflow if they are bulky and placed in the way of breeze paths. 

Design strategic layouts 

“In living rooms, opt for floating furniture layouts rather than pushing everything against walls,” suggests Ms Tan. 

Conversely, corner-blocking layouts – such as those formed by L-shaped sofas pushed into corners – create dead air zones, she adds. “These spaces become heat traps because air can’t cycle out. Instead, leave a gap – you can place a tall plant in this gap instead.”

Avoid placing large furniture – such as sofas, wardrobes or shelving units – directly in front of windows or along the natural breeze path, as this blocks cross-ventilation. 

A rule of thumb: If air cannot “travel” in a straight or gently flowing path across the room, it will stagnate. 

Optimise materials

Ms Tan suggests switching to lighter, breathable textiles – for instance, linen bedsheets, cushion covers and throws.

“Solid, heavy materials like leather retain heat longer,” she says.

For those renovating their floors, she says: “Marble, tile and terrazzo floors tend to stay cooler underfoot, compared with wood, vinyl or carpet, which tend to trap heat.”

Dr Zheng adds: “Stones and tiles feel cool because they draw heat quickly from your feet, and they also lose heat quickly at night.

“Whereas wood and vinyl are insulators, so they feel warm and tend to radiate heat back into the room.”