Insulating your home is one of the most cost-effective ways to save energy and money. The Department of Energy provides a fact sheet on how to measure the thickness of the attic insulation and calculate its R-value. Table 1 may also be useful. It's important to note that the effectiveness of insulation depends on how it is installed.
To get a customized level of insulation for your home, use the DOE ZIP Code Isolation Program. The overall R-value of a wall or roof will be different from the R-value of the insulation itself, as some heat flows around the insulation through studs and beams in wooden or steel structures (thermal bridges). Even if your home is newer, adding insulation can pay for itself in a few years. When choosing insulation, consider the space you have, the apparent density of the materials, ease of access, cost, and whether you are building a new house or improving an existing one.
The R-value measures the performance of insulation by measuring its resistance to heat flow over time. Use the chart and climate map below to determine what level of insulation is best for your home. Make sure that the roof or walls can support the additional weight before installation. The Home Energy Saver tool can help you determine how much insulation should be added and where it should be added for maximum energy efficiency.
For more information on insulating materials, installation methods, and benefits, see Types of Insulation. The Federal Trade Commission has a standard (Title 16, Business Practices, Part 460, Labeling and Advertising of Home Insulation) to protect businesses and consumers from misleading advertising and improper installation. If you are building a new home, you can consider installing insulation at the bottom of the roof covering and sealing the attic space to create an “unventilated attic”. If you're not sure what type of insulation already exists in your home, take a sample to an insulation expert.
