Adding insulation, combined with sealing air leaks, is one of the most cost-effective energy-saving improvements you can make to an existing home. It can cut heating and cooling costs by 15 percent or more.
While every house is different, the basic rule of insulating is the same for all homes: install insulation on any surface separating a heated space from an unheated space-attics, walls, basement walls, floors and crawl spaces. Even if your home already has some insulation in these areas, there can be great benefits in adding more insulation, especially in your attic. Sealing air leaks around vents, chimneys, wires, and light fixtures must be part of any insulation job. Also, when installing insulation, include a vapor retarder if possible. If you are adding insulation to an area that already has a vapor retarder, then another vapor retarder is not needed.
An advanced energy assessment of your home will include an insulation inspection to identify the amount of insulation you have and how much more you need. The amount of insulation (measured in terms of thermal resistance called R-value) and the type of insulation that is best varies from home to home and depends on several factors: (1) how much insulation is currently in place, (2) the accessibility and space available for the insulation, and (3) the climate zone of the home.
The U.S. Department of Energy (DOE) divides the country by zones; Minnesota falls into two of the colder weather zones that call for higher R-values. DOE offers an Insulation Fact Sheet at http://www.ornl.gov/sci/roofs+walls/insulation/ins_08.html to help determine the best type and the amount of insulation needed. For more detailed information on insulation, see pages 19-30 of the Division of Energy Resources’ Home Envelope energy guide at http://mn.gov/commerce/energy/images/Building-Envelope-Guide.pdf on the DER website (www.energy.mn.gov).