How To Keep Your House Cool Without AC – Part 3.
When 100-degree heatwaves strike, should you close windows or leave them open? How do you keep the upstairs cool naturally?
Sit back with a glass of ice tea and practice using that old paper fan correctly. Move it languidly not fast! Practice with your non-dominant hand so you can actually do something with your dominant hand – like scrolling down to read more.
Reduce And Reflect Sunlight
Sunshine is wonderful stuff, but it’s your enemy when you want to stay cool. Anything you can do to keep it from shining onto and into your house will help keep you cooler. That includes making your house and roof more reflective—reflective roof paint can make a sizable difference—and, especially, keeping sunlight from shining in through your windows. Why is the last so important? Sunlight is much more than visible light; it also contains ultraviolet (UV) radiation and infrared radiation (heat). Heat doesn’t travel through glass very quickly, but visible light and UV radiation do. And when they hit air molecules, or solid objects like your skin or the floor of your living room, a significant portion of their energy is converted to heat. This mini greenhouse effect is great when it’s cold outside, but not so good when it’s hot.
Closing drapes and shades can help keep out the visible light and UV rays so they don’t get converted to heat, so close them whenever your windows are closed—especially on windows that get direct or reflected sun. In an older home, functional shutters are fabulous for this. Even covering the windows with a portable screen or a large sheet of cardboard will keep the sun’s rays out quite effectively. Insulated window coverings are even more effective, as they help block the heat portion of the sunshine that comes in through the glass and frame.
If living in a cave bums you out and you have some money to spend, you can cover the insides of windows with special film to help block a portion of visible light and UV rays without totally blocking visibility. Removable film allows you to take it off during the winter when you want the free solar energy. There are also window shades designed to let you see out but still block most of the direct rays. Mesh ones don’t need adjusting; slatted ones may need to be adjusted as the sun moves. Replacing your windows may be an option if you have money to spare (and tax incentives may help offset the cost), especially if they are leaky and old; doing so won’t pay for itself as quickly as using drapes, shades, or removable film. If you go this route, be sure to choose windows with a “Solar Heat-Gain Coefficient” that matches your climate.