Installing attic insulation is an important part of any effort to make your home more efficient. Attic insulation does two things to increase energy efficiency. In the winter it keeps the warm air in your home from rising into your cold attic. This is a very important function as warm air naturally rises and without any insulation you will have a hard time keeping your house warm on cold winter nights. Secondly attic insulation helps keep the hot air that fills up your attic in the summer from pushing down into your house. On a recent early summer day here in Austin Texas one of our insulation installers measured the air temperature inside the attic to be 156 degrees. Even a little bit of hot air of that temperature making its way into your house can drastically increase the cost of cooling your home.
The most important thing when installing attic insulation is getting good coverage of all areas. Having holes or gaps in your insulation will drastically reduce its effectiveness. This is why many people prefer to have professionally installed blow in insulation in their attics instead of using the batts or blankets that you can do yourself. Batts do offer a little bit better insulation per inch of thickness, but they are much harder to get complete coverage with. Blown insulation can be blown into all the corners and crevices in your attic to make sure you don't have any gaps or leaks and usually costs less to install both in material and labor costs.
Attic insulation is measured in R values. R value is a measure of thermal resistance, but all you need to know is the higher the number the better the insulation. The government has published recommended R values for attic insulation in different areas of the country. You can visit http://www.ornl.gov/sci/roofs+walls/insulation/fig2.html to see a map of climate zones with recommended R values. These recommendations can provide a good baseline for what your home needs, but many experts feel that these government estimates are too low and that homeowners who go above the recommended R value for their climate zone still see significant energy savings.
Understand how attic insulation works is also important for figuring out if you need more attic insulation, it works on much the same principle as a down sleeping bag. it traps little pockets of air that then form an air barrier between the inside and outside temperatures. These pockets of trapped air are not allowed to move freely, preventing them from cycling through the insulation and transferring heat across it. This is important because, much like a sleeping bag, insulation that has been pressed down, trampled, or otherwise de-fluffed will not be as effective. As insulation settles and gets pressed down the pockets of air get pressed out dramatically reducing its effectiveness.
This is why it is particularly important for owners of older homes to increase their attic insulation, while they may have had adequate insulation when they were first built, over time their R value has decreased. Moisture getting into your insulation can also rapidly reduce its R value by weighing it down and making it less fluffy. You can tell whether or not your attic insulation has lost R value by looking in your attic and seeing if it still looks relatively fluffy or not. If it is matted down and trampled it is time to replace or add more insulation.
Barret Hudson is a representative of Green Collar Operations. We are an Austin company that helps homeowners dramatically reduce their utility bills through home weatherization. More information at www.greencollaroperations.com
