by Eli Chamberlain
Summer is here and its hotter than ever. Keeping your home cool in the summer can be a real challenge, particularly if you don’t have air conditioning. At Hopi and Navajo very few households have air conditioning so it’s important to know how to keep cool without AC.
It may sound obvious but the most important way to keep your house cool is to keep the heat out during the day. Heat enters the home through two primary pathways, windows and attic spaces. Windows allow wanted daylight in but can also let heat in when they are in direct sunlight. Shading the window on the exterior is the most cost effective option for reducing solar heat gain. This can be accomplished in a variety of ways but shade screens are the most popular. Shade screens look like normal screens but they cover the entire window on the outside. The screen material is a little thicker than a normal screen which helps block up to 80% of the solar energy striking the window but still allows good visibility looking out. Shade screens are also removable to allow wanted solar heat gain in winter. Windows that use Low-E or Low Emissivity coatings reflect the solar energy striking the window to keep the house cooler. Low-E windows will also block wanted solar heat gain during the winter months so they may not be the best option for year round comfort. Using blinds and other interior window coverings do not help nearly as much as exterior shading. By the time the solar energy reaches the interior window covering it is already inside the window and is heating the house up. Other ways to shade windows on the exterior are with awnings, exterior shutters or even plants.
Attic temperatures can reach 150 degrees during hot summer days. If there is not an adequate thermal barrier between the inside of your house and the attic space much of this heat will transfer to the interior of the house. Insulation provides this thermal barrier to keep the attic heat out during the summer and the warm air inside your home during the winter. As a general rule of thumb you should have at least one foot of insulation in your attic and it should be evenly distributed. Compressed or missing insulation can create easy pathways for heat transfer to bypass other areas that are well insulated. Skylight shafts, attic accesses, and vertical “knee walls” that separate attic space from living space are all frequently over looked when insulating. An infrared camera on a hot day is a great tool to locate insufficient or missing insulation. A properly installed layer of insulation can make a dramatic effect on the comfort of your home year round.
Airing your house out in the evenings and then closing the windows during the day can help to keep the heat out. A simple box fan placed in a window pointing out will do a great job of cooling the house off at night. Ceiling fans also help to keep you cooler but they don’t actually cool the room down. As the ceiling fan pushes air across your skin it makes you feel cooler by pulling heat off of your body. This can also be a very cost effective way to feel cooler but remember to shut the ceiling fan off when you leave the room because it won’t actually cool the room off.
If upgrading your attic insulation and shading your windows is still not enough to keep your house cool, then you might want to consider an AC unit. The most economical option is a window unit that is easily to install and remove. Central AC units are much more expensive but do a better job of keeping temperatures even throughout the house. Air conditioners have SEER ratings which show how efficient they are at removing heat from your home. The higher the SEER rating, the more efficient the unit is.
It is sometimes difficult to determine what the best and most cost-effective options are to keep your house cool. A professional Home Energy Auditor can help you make these decisions so you don’t waste your money on something that won’t help you.
Photos courtesy of APS and Loren Anderson www.lorenandersonphoto.com