To Air is Human, To Insulate Divine

ts winter again, and boy, don't we know it New England. There's more snow on the ground than we can ever remember having! So I thought we might take a look at some of low cost ways you can help save thermal energy in your abode. The contributors to heat loss in a home are: conduction losses to the exterior, radiant losses from the exterior, convection from the exterior, and air infiltration/exfiltration. Here are a few examples of the efficacy of reducing conductive and air movement heat losses with simple but surprisingly effective methods. Let's take a look at air leaks. Usually infiltration happens on the lower floors of a building and exfiltration occurs at the top floors due to the stack effect (in a heated building, the indoor air is buoyant and applies pressure to the envelope. The pressure increases with the height of the envelope). Air infiltration not only makes a building consume more energy, but it makes it "drafty and cold", especially if you are sitting next to the source of the leakage! Take a look at the thermal imaging photos below. Here we see an unused air conditioning vent spewing out cold air on the first floor (stack effect). You can't see the air with thermal imaging camera, but you can see the cooling effect the air has on the walls and ceiling. For this retrofit I used a piece of magnetic plastic sheet. You can see in the after thermal image the dramatic reduction in airflow and the effect of adding a bit of insulation to the open areas of the vent. The delta T reduction between the vent and the ceiling was about 30%. Not bad, but I thought I could do better!