Homeowners typically give little thought to the performance of their home’s duct system. But the tightness and cleanliness of an HVAC forced air distribution network are important factors in the overall efficiency of the home, and they have significant impacts on indoor air quality for the occupants.
All of the conditioned air that you breathe in your home passes through a serpentine, mostly hidden network of ducts, and those ducts themselves usually pass through the most unpleasant parts of your house. If you have ever spent any time in your crawl space or in your attic, which is where the ducts are usually located, you know that neither place is where you would choose to sit around and breathe the air. So it stands to reason that you don’t want that air to mix with the conditioned interior of your home.
Air leaks in a typical duct network, however, accomplish exactly that. Conditioned air pushed by the air handler is delivered through a supply network leading to the registers throughout the home. Along the way, this pressurized air will find every possible unsealed leak and bleed out into your crawl space and/or attic. The money spent running your air conditioner or furnace escapes with it, and the rooms where the air is supposed to end up are starved of what they need to make them comfortable.
On the return side of the system, air is being pulled back towards the air handler, creating negative pressure inside the ducts. Leaks along this pathway allow unconditioned air to be sucked in from crawl spaces and attics, along with dust, moisture, moldy smells, rodent hairs . . . you name it. The air filter that everyone changes with perfect regularity (you do, don’t you?) helps to cleanse some of these less desirable components from the air stream. But over time, the interior of most every duct system gets coated with a layer of unpleasantness.
Leaky ducts can waste as much as 35% of your HVAC system’s operating costs. And the introduction of unwanted air from crawl spaces and attics can contribute to a host of respiratory and allergy related health problems. Sealing and cleaning a home’s duct system will have overwhelmingly positive impacts on both the energy efficiency of an HVAC system and the quality of the air that you breathe inside your home. Take a deep breath and consider why you shouldn’t be doing it.