FT NEWS

Summer is here in full force. With temperatures rising to unbearable extents in our hot country, it becomes a challenge to keep cool during the season. But, thankfully, there are measures we can take to create comfortable conditions inside our homes. Here are some passive cooling techniques, some wall and roof treatments and some structural upkeep tips that will aid in cooling down your home naturally. They reduce your air conditioning bills and make you more gentle towards the environment. Try them now!

1. Paint the roof and terraces white
A considerable amount of heat gain in buildings occurs through the roofs, simply because they are large surfaces directly under the sun. However, it is proven that this heat gain can be reduced by more than 60 per cent by turning any roof into a reflective roof. Simply painting the roof and terraces white (with a sun-reflective white paint) can aid in reflecting the heat from the summer sun all through the day. Hydrated lime (our good old-fashioned chuna) is a great (and easily available) alternative used for this purpose. Reflective roofs are also favourable for cooling down penthouse apartments and flats located on the topmost floor of a highrise building.

2. Top with greens
Installing a green roof is another sure-shot way to block the heat coming in from the roof. Green roofs insulate the surface, keeping the indoors cooler than any traditional roofing system.

3. Shade, shade, shade
Did you know you could lower the temperature up to 4°C with clever shading? Install exterior overhangs for the south-facing windows and canopies for doorways to shut out the direct heat of the high summer sun.

For hot-dry and warm-humid climates, I recommend year-round shading that does not hamper the ventilation of the building. For a composite climate (comprising a very hot summer season, a humid rainy season and a short, cool winter season) areas, I suggest overhangs or eaves that can be fitted at different angles to block the summer sun but

For apartments and homes where overhangs cannot be fitted, vertical fins and louvres can work well. Though fins and louvres obstruct the outside views, they can be adjusted at various angles as per the lighting and ventilation needs.

The east-facing and west-facing windows and openings also need to be shaded from the morning and evening sun. Due to the low angle of the sun path, vertical shading and egg-crate shading devices (a combination of vertical and horizontal shading) best suit the east and west directions.

If you are a green lover, you can have a vertical garden or a screen with climber plants to shade your east and west windows, balconies and other glazed surfaces. Plants soften the views and add an element of interest to the facade of the building.

4. Texture your sunlit walls
Walls that are exposed to sun for a large duration of the day are likely to invite a lot of heat into the home. Texturing increases the surface area of the walls, allowing them to stay much cooler than that of plain walls. The rough texture creates self-shading and also offers a greater surface area for re-radiation of absorbed heat. In the picture, you can see how the texture itself shades part of the wall, its white colour reinforcing the cooling effect.

5. Double-glaze your openings
Heat coming in through glass surfaces fails to pass back through the glass (due to the greenhouse effect), raising the temperature inside the home substantially. Double-glazed windows, doors and skylights have two layers of glass with a small gap between them. This reduces the ingress of heat through the openings, thereby reducing the cooling load of the home. Using tinted or toned glass that has a low solar-heat gain coefficient (SHGC) adds to the output.

6. Allow for the stack effect
The stack effect or chimney effect refers to the phenomenon of the rising of hot air inside a closed area. To work this out in your home, install operable skylights or louvres in the double-height spaces and staircase wells in your home. The prevailing warm air rises up and exits from the vents, leaving comfortable cooler conditions in the indoor space. It also allows for regular refreshing of air due to natural ventilation.

7. Insulate well
Walls, floors and ceilings should be properly insulated to shut the flow of heat due to conduction. This directly reduces the home’s dependence on the AC for cooling. You can check with your engineer if your home is insulated as per the required standards. (Or you can refer to this bulletin on building insulation by IGBC) If not, existing structural systems can be retrofitted with spray foam, sponge foam, silicone or rubber and sealed with sealants and weather strips.

Improper hardware joinery, cracks and crevices can also let a lot of heat into the home through draughts. Hire specialists to check and repair your openings, appliance joints and hardware to obtain utmost insulation.