I handle the temperature control of our home with a forced air heating plus cooling system. Both the oil furnace plus air conditioner utilize a duct system. The air duct is concealed in the walls, ceilings, plus basement, plus is linked to supply plus return vents in every room of the house. The heated plus cooled air passes through this complex network of pipes many times per day. The many sections of air duct are connected together by sheet-metal screws, plus the seams are then further sealed with mastic. Over years of usage plus possible corrosion, most residential duct systems leak at the seams plus develop small holes which waste energy plus lead to room-to room pressure imbalances. Even minor flaws in the duct method result in major complications with oil furnace plus air conditioner performance. Higher running costs, longer cycles, more frequent repairs plus premature unit failure are some of the consequences. Leaks in the duct method can often be blamed for hot/frigid spots in the house, drafts, excess humidity, unpleasant smells plus poor indoor air quality. It is a wonderful system to hire a certified Heating plus A/C corporation to inspect the duct method every few years. The sealing process is not overly involved, plus causes no mess or destruction to the home. The Heating plus A/C corporation covers all supply plus return vents before blowing a steady stream of air into the duct system. The air contains adhesive polymer particles plus is put under serious pressure. As the air escapes through holes in the ducts, the particles stick to the edges, build up plus create a slender seal.