To begin to answer this question, you must first find out how much insulation you already have and then determine how much more would be cost-effective. Many older homes have less insulation than homes built today. A qualified home energy auditor will include an insulation check as a routine part of an energy audit. For information about home energy audits, call us at Premier North Insulation. State energy offices are another valuable resource for information. An energy audit of your house will identify the amount of insulation you have and need, and will likely recommend other improvements as well.
If you don’t have someone else inspect your home, you’ll need to look for insulation in several places. Figure 1 shows the places in a typical house where insulation should be installed. These are the areas you should check. In each location, you’ll need to measure the thickness of the insulation and identify which type of insulation was.
Determining the R-Value You Need for an Existing House
The amount of insulation you need depends on the climate, type of heating (gas, oil, electricity) you use, and the section of the house that you plan to insulate. The attic is the first area to consider because it is accessible and therefore less expensive to insulate.
The first step is to compare the R-value of your insulation with the recommended R-values for your house and your type of space heating. Using these recommended R-values, subtract the R-value of the insulation already in your home. The result will be the R-value you should add.