Tips for keeping your house cool, even in the heat of summer.
The Basics of Comfort
There are two things that factor into our comfort - temperature and humidity. Imagine standing in the shade on a dry, 25 degree day. Now imagine standing in a steamy, humid jungle on a 25 degree day. Same temperature, but drier air is more comfortable.
Why Your House Gets Hot
There are two basic ways in which your house heats up. Solar gain, and air loss. Solar gain is the addition of heat through solar radiation. Think of it like feeling the heat of the sun on your skin, which may feel hotter than the air temperature itself. Air loss is simply hot outside air getting into your house.
Strategies:
Reduce Solar Gain
Any windows, but especially those that get direct sunlight, will contribute to solar heat gain. Covering windows with blinds or curtains dramatically cuts down on the amount of heat that comes in. The more opaque the material, the better.
Reduce Air Loss
Although it may be tempting to open a window to cool off, if the outside air temperature is higher than the inside temperature, you will actually be making things worse. Try to keep windows and doors closed as much as possible, unless you need the fresh air.
Exchange Air at Night
Because the temperature drops at night, that is a great time to cool the house off. As soon as the outside temp drops below the inside temp, open all the doors and windows. Turn on all your bathroom fans and your kitchen range hood (if it vents outside). This will depressurize your house, and draw cool outside air in. If you have portable fans, position them so they are drawing air from outside and blowing it inside.
Turn on Your Furnace Fan (No, Really)
Many modern furnaces have a mode where the fan runs at low speed to circulate air throughout the house, but the furnace does not ignite. Moving the air around will help to keep the temperature more consistent between all parts of the house. If your furnace is in a basement, you will get some passive cooling as the air passes through the ducts down there.
Dehumidify
Remember how the drier the air is, the more comfortable it will feel? Dehumidifiers can help lower the moisture in the air, although they do create some heat as they run. This is only recommended if you have a humid house.
Use a Fan
Fans don't remove heat, but they do help us feel cool. Air moving over your skin helps with both evaporative and convective heat transfer.
Use a Damp Towel
It takes 970 times as much energy to evaporate water than it does to raise its temperature by 1 degree. This is what makes sweating such an effective cooling mechanism. By putting a damp towel around your neck, you will be getting the cooling effects of sweating, but your body won't have to do the work!
What Not to Do:
Opening the Fridge or Freezer
Refrigerators don't get rid of heat, they just move it from one place to another. They take heat from inside the appliance, and dump it into the room. The components that make this possible (compressor, fans) actually generate some heat as they run. Opening the fridge door to try and cool down the room is counterproductive. All the heat that gets into the fridge now has to be removed again, and this process actually creates more heat.
Upgrades:
In addition to these strategies, there are some upgrades that can make your home more energy efficient, and cooler in the summer.
Upgrade Insulation
Insulation resists the movement of heat. It doesn't just keep things warm, it also keeps things cool. Adding insulation to your attic prevents the intense heat up there from being transferred to your house. If you are replacing or upgrading siding, consider adding insulation board to the exterior walls.
Heat Pump Water Heater
Like a fridge, a heat pump doesn't create heat, it just moves it from one place to another. In this case, it grabs heat from your home, and uses it to heat your water. Since this water eventually goes down the drain when you cook or bathe, this heat is removed from the home.
Upgrade Windows
New windows are not only significantly better insulated, they have a Low-E (low-emissivity) coating on them that helps reflect sunlight and reduces solar heat gain.
Plant Trees or Shrubs
Planting trees or shrubs around your home can help keep it cool by providing shade. For optimal efficiency, plant deciduous trees. Since they lose their leaves in winter, you will get shade all summer but also get a bit of extra solar gain in the winter.
Key Points
Reduce your solar gain by covering windows.
Keep windows closed during the day.
Cool the house off at night by opening windows, and running bathroom and kitchen fans.
Consider upgrading insulation and windows.
Plant trees and shrubs near the house to provide shade.