Last winter, I noticed some problems with the furnace. It seemed to be running a lot more often and longer than usual. The heating plan was struggling to keep up with the temperature control setting and the home felt cold. There was a definite difference in temperature between the numerous rooms. I also had to dust and vacuum more frequently. Because I am conscientious about air filter variations and scheduling professional repair in the fall, I was surprised by the complaints with the furnace. I called my regular Heating as well as Air Conditioning corporation and explained my troubles. He immediately suspected the air duct as the source of the troubles. After completing a testing of airflow through the air duct, he determined that approximately 25% of the heated air was escaping through holes and cracks at the seams. These same leaks were drawing in cold, dirty outdoor air and spreading contaminants throughout the house. I had no plan how duct sealing could be completed without a major mess. The air duct is installed behind the walls and ceilings. The corporation explained a fairly modern technology called Aeroseal works to repair leaks from the inside. He first sealed off the supply and return registers. He then pumped highly pressurized air into the air duct. This air was laced with adhesive polymer particles that are non-toxic. As the air escaped through the holes in the ducts, those particles clung to the edges and steadily built up to supply an airslim seal. The whole process was completed within a couple of hours. It is guaranteed to last many years and makes a huge improvement in the comfort, cleanliness and efficiency of the home.