As our national holiday approaches, so do the hottest days of summer. Let’s talk about low-energy ways to keep cool without turning up the air conditioner.
The easiest way to heat-proof your house is in the planning stages. It’s important to have a well-ventilated attic and roof. Good insulation, good overhangs to block solar radiation, and proper window placement go a long way to improving your comfort level in the dog days of summer. So does the orientation of the house — a north-south orientation with west-facing windows is NOT a good idea if you can avoid it. Remember that the hottest part of the day is late afternoon.
What if you have an existing structure and you aren’t in the process of renovating your home? Try thermal blinds, or better yet, heat-mirror film or glazing on your windows. The latter can cut 10-20% of the solar heat gain in your house. The trick is to stop the heat before it gets inside — which is why the old trick of putting tinfoil on the inside of the windows doesn’t help much. On the other hand, outside shutters, louvres and awnings do work.
Another good strategy is to plant deciduous trees strategically for the time of day and year. Never underestimate the cooling properties of greenery! And have you ever sprayed a fine mist of water around the room to cool it, or placed a bowl of water in front of a fan? Evaporative coolers work on the same principle, drawing heat energy out of the air in order to evaporate moisture. Another simple trick is to move your sleeping quarters downstairs for the summer if you can.
Using air movement to your advantage is easy — open your windows in the coolest part of the house in the morning, then close them and wait until the cool of the evening before reopening them (and keep those window coverings closed in the meantime). Open windows on opposite sides of the house for passive ventilation, and try to catch the prevailing wind direction. You can create a “heat chimney” by opening lower and upper windows — or a venting skylight — which will draw cool air in at the bottom, and vent hot air out at the top of the house.
Finally, try not to keep the house too cool. Many of us over-compensate for summer’s heat and reduce the indoor temperature to a level that we’d never tolerate in the winter! It should be possible to stay comfortable at 24-25 degrees Celsius. Staying hydrated, eating lightly, wearing a hat and light cotton clothes will also help you to stay cool naturally. Now go out and enjoy the festivities, wear sunscreen, and have a great holiday!