Air leaks carry a large amount of heat. A home that is not sealed properly will allow heat to leak in or out, depending on the season. Look for areas where leaks can occur, such as cracked or missing caulking
around doors and windows. Plumbing, heating or electrical equipment that passes through the house also is an area to check for air leaks. Fiberglass insulation is a good insulator but poor air barrier, so dirty fiberglass insulation is a good indication of air leaks.

Air leaks can be found in a home using a number of techniques. Infrared cameras will show places in a home where air is leaking, but homeowners can use things as simple as an incense stick, a flashlight or even the back of their hand to search for air leaks.

Areas that are often not  insulated and overlooked for heatloss and air leaks.

The NDSU Extension Service has developed a program using infrared thermometers to check for air leaks in a home. The infrared thermometers are available for loan from county offices of the NDSU Extension Service, and information on areas in the home to check will be provided.

In addition to heat losses, leaks in a home can lead to problems with insects and moisture.