Hi all, Climate Master John Fischer here with KLCC's Living Less Unsustainably.
There's nothing like a heatwave to make you realize how hot it is - and motivate you to keep your home cool with as little energy use and climate impact as possible.
The first rule - don't let the heat in. Blocking the sun with an outside shade is much more effective than an inside shade. The sun will make the curtain warm inside the house, which will heat up the air around the curtain, which will move around, and warm the whole room. A great lesson in radiation, conduction, and convection - but a poor substitute for keeping the heat out in the first place.
Professional outdoor blinds are best, but you can improvise with an old sheet to convince yourself that the cost is worth the benefits - or just use the sheet during hot spells.
A well placed bush, or even a summer vine that grows up to shade a window during the warm season can be very effective. In the long term, having a deciduous tree on the south you house can really help keep things cooler - eventually.
The second - easier to implement strategy is the window dance. Open them when it's cool. Close them when it's hot. A fan blowing hot air out is most effective, but blowing cool air in early in the day can provide great cooling for a specific area. Putting storm doors back in winter position can help keep the heat out too. Don't forget to put them back into screen mode when the heat abates.
An indoor / outdoor thermometer can take the guesswork out of when to open or close. Of course if you are not around at 11:00 a.m. to close windows, the dance is not as effective - or fun.
And don't forget the second law of thermodynamics just because you are overheated. Temperatures will try to equalize across differences. If you must rely on air conditioning, it is always more efficient to run it when you need it - when you are home - than to keep the house cool when you are away - always. A programmable thermostat can help with the coming home to a hot house problem.
I'm John Fischer with living less unsustainably.