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• Insulation
• Insulation Types
• Needs — By Region
Brief #3
Basement and Crawl Space Insulation
Attic Insulation
Duct and Pipe Insulation
Wall Insulation —  Wood Frames
Wall Insulation – Masonry Cavities
Wall Insulation – Installed on the Inside
Wall Insulation – Installed on the Outside

For most cases with historic buildings, adding a vestibule is not recommended.
• History, brick, plaster, seaweed, moasonry wall, fireplace, etc.

*Picture/relate to Robin



Heat loss through the ceiling and walls in your home could be very large if the insulation levels are less than the recommended minimum. You should check to see if the level of the attic and wall insulation of your home is at least at the minimum recommended amount. When your house was built, the insulation recommended at that time was installed. Given today’s energy prices, and that future prices probably will be higher, the level might be inadequate, especially if you have an older home. In 1997, the U.S. Department of Energy updated its recommended insulation R-Values.


If the attic hatch is located above a conditioned space, check to see if it is at least as heavily insulated as the attic, is weather-stripped, and closes tightly. In the attic, determine whether openings for items such as pipes, ductwork, and chimneys are sealed. Any gaps should be sealed with an expanding foam caulk or some other permanent sealant. If you have recessed light fixtures, determine if they are IC rated fixtures. It is strongly recommended that only air tight-IC rated fixtures be used. Other types allow large amounts of your heating dollar to escape into the attic. If you do not wish to purchase new IC rated fixtures, be certain to allow a three-inch space around any recessed lights. This will prevent the recessed light from overheating.

While you are inspecting the attic, check to see if there is a vapor barrier (retarder) under the attic insulation. The vapor barrier might be tar paper, kraft paper attached to fiberglass batts, or a plastic sheet. If there does not appear to be a vapor barrier, you might consider painting the interior ceilings with vapor barrier paint. This reduces the amount of water vapor that can pass through the ceiling. Large amounts of moisture can reduce the effectiveness of insulation and promote structural damage. Make sure that the attic vents are not blocked by insulation. You also should seal any electrical boxes in the ceiling with flexible caulk (from the living room side or attic side) and cover the entire attic floor with at least the recommended amount of insulation.


Checking a wall’s insulation level is more difficult. Select an exterior wall and turn off the circuit breaker or unscrew the fuse for any outlets in the wall. Be sure to test the outlets to make certain that they are not "hot." Check it with a lamp or portable radio. Remove the cover plate from one of the outlets and gently probe into the wall with a thin, long stick or screwdriver. If you encounter a slight resistance, you have some insulation there. You could also make a small hole in a closet, behind a couch, or in some other unobtrusive place to see what, if anything, the wall cavity is filled with. Ideally, the wall cavity should be totally filled with some form of insulation material. Unfortunately, this method cannot tell you if the entire wall is insulated, or if the insulation has settled. Only a thermographic inspection (discussed below) can do this.

Basement or Crawl Space

If your basement is unheated, determine whether there is insulation under the living area flooring. In most areas of the country, R-25 is the recommended minimum level of insulation. The insulation at the top of the foundation wall and first floor perimeter should have an R-Value of 19 or greater. If the basement is heated, the foundation walls should be insulated to at least R-19. Your water heater, hot water pipes, and furnace ducts should all be insulated.


No matter what kind of insulation you buy, check the information on the product label to make sure that the product is suitable for the intended application. A good insulation label should have a clearly stated R-value, and information about health and safety issues. An informative label should state:

  • The type of insulation material;
  • The R-value (measured at 75F);
  • The types of spaces that can be insulated;
  • Safety precautions in application and use, including any fire-hazard related restrictions;
  • The quantity in the package;
  • The name and address of the manufacturer or distributor.

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