Last winter, I noticed that the furnace was starting up more often and running for much longer cycles.
It seemed as if it was operating non stop, and yet the house felt chilly.
There were inconsistent temperatures from one room to another. When I noticed a significant increase in my monthly heating bill, I called an HVAC contractor for repairs. The technician took the furnace apart, inspected all of the components and tightened a few wires. He didn’t find anything worrisome. He then tested the ductwork and discovered that approximately twenty-five percent of our heated air was escaping. These same holes and cracks were allowing outside, unconditioned air to enter the house. Because the full amount of heated air produced by the furnace was failing to reach the various rooms, the system was forced to work a lot harder and use more energy. The duct system is largely concealed behind walls and ceilings and in the crawlspace. I worried that fixing the problem would require a huge, messy and invasive renovation project. Instead, the contractor explained a process called Aeroseal. This fairly recent innovation seals flaws in the ductwork from the inside. The contractor first blocked off all of the supply and return registers. He then pumped highly pressurized air into the duct system. This air included adhesive polymer particles that are entirely non-toxic. As the air flowed out of the holes and cracks, those particles steadily built up along the edges and formed a tight seal. The Aeroseal process is guided by a computer program and warrantied for ten years. It took a couple of hours to complete. The technician then repeated the duct testing and proved the effectiveness of the results.