Posted: October 2009

Does your home need more insulation? Unless your home was constructed with special attention to energy efficiency—which goes for most houses built before 1990—adding insulation can reduce your utility bills. It can also reduce the draftiness of older homes, making them feel warmer without cranking up the heat.

Adding more insulation where you already have some, such as in an attic, will save energy. You can save even greater amounts of energy if you install insulation into places in your home that have never been insulated. These might include an uninsulated floor over a garage or crawlspace, or a wall that separates a room from the attic

How Much Insulation Do I Already Have?

Look into your attic

We start with the attic because it is usually easy to add insulation there. The following table will help you figure out what kind of insulation you have and what its R-value is.

Look into your walls

It is difficult to add insulation to existing walls unless:

• You are planning to add new siding to your house or
• You plan to finish unfinished space (like a basement or bonus room).

If so, you need to know whether the exterior walls are already insulated or not. One method is to use an electrical outlet on the wall, but first be sure to turn off the power to the outlet. Then remove the cover plate and shine a flashlight into the crack around the outlet box. You should be able to see whether or not insulation is in the wall. Also, you should check separate outlets on the first and second floor, and in old and new parts of the house, because wall insulation in one wall doesn't necessarily mean that it's everywhere in the house. An alternative to checking through electrical outlets is to remove and then replace a small section of the exterior siding.