Thermal Imaging: A Diagnostic Test for Home Energy Ills

A challenge that many homeowners face in the winter is escaping heat, resulting in a colder home and a higher heating bill. Even if a building is insulated, cold air still can find its way in. One way of identifying problem areas causing loss of heat in your home is thermal imaging—using an infrared camera to identify trouble spots so that defects in insulation can be pinpointed and addressed.

Thermal imaging involves taking pictures of walls in your home to determine where air leaks or weaknesses in insulation are. It shows the different temperatures of surfaces, so cold spots become evident. An infrared camera is similar to a typical camera, but, instead of sensing light, it senses infrared energy, or the heat given off by objects. This is then formed into an image, which allows the viewer to pinpoint areas where insulation may be missing or defective or where cold air is entering through a gap. The imaging is completed and interpreted by a thermographer, a person trained in both the use of the camera and building construction, allowing them to accurately analyze the pictures taken.

Thermography reveals areas in the wall of this living room (dark blue cold spots) where insulation is not installed properly.

The same living room as seen normally

For example, colder spots on a wall would indicate a problem with insulation, such as insulation that has settled over time to leave gaps, or voids where the installers missed certain spots. An abnormally cold wall may indicate a complete lack of insulation in that area. The use of thermal imaging reveals things that would otherwise only be seen by taking apart the walls.

Thermal imaging can also reveal air leaks, the presence of moisture, thermal bypasses (air moving around or through insulation), and thermal bridges (for example, where heat is conducted much more quickly through the studs within a wall than through the insulation between the studs).

Homeowners in Massachusetts may be able to get free thermal imaging done through Mass Save, an organization sponsored by Massachusetts energy companies. After taking an online home energy assessment, Mass Save or Renew Boston can send out an energy specialist who will complete a free home energy assessment. This will include thermal imaging, provided that there is a 20 degree difference in temperature between the outside and the inside of the house, to get satisfactory readings. So, you may want to schedule an in-home energy assessment during the colder times of the year to ensure that thermal imaging is included.

Thermal imaging and other diagnostic tests, such as a blower door test, can also be done through private contractors for a fee. A blower door test depressurizes the interior of the house and allows thermal imaging to be more accurate, as well as testing for air leaks. Mass Save provides an online list of approved home performance contractors, which will vary depending upon the customer’s energy provider.

Third-party infrared testing ranges widely in price, as some companies charge by the hour and some by the square foot. You could expect to pay at least several hundred dollars, so taking advantage of the free assessment is definitely worthwhile. If the test reveals that insulation work is needed, Mass Save and Renew Boston can subsidize 75% of up to $2,000 in insulation work.

—Sean Yarolin