Wednesday, July 14, 2010

Air Ducts 101

What You Can't See May Be Costing Hundreds of Dollars in Wasted Heating and Air Conditioning Bills!

Your heating and cooling systems use more energy than any other system in your home. Typically, 46% of your entire utility bill goes for heating and air conditioning alone. For many homeowners, a large chunk of that heating and cooling bill may be completely wasted...and the culprit is hidden out of sight beneath your feet and over your head.

Your home’s air duct system is a complex network of tubes made of sheet metal, fiberglass or other materials that runs throughout your walls, floors, and ceilings, carrying heated or cooled air from your home’s furnace and central air conditioner to each room. But if these air ducts have leaks or are poorly insulated, as much as 60% of your heated or cooled air can be lost before it even reaches the registers in these rooms. That can result in a lot of wasted energy...and money. As well, ducts that are damaged or don’t work properly can create serious, life-threatening carbon monoxide (CO) problems in the home.

Sealing and insulating air ducts that are in unconditioned spaces -- such as an attic, crawl space or basement -- is extremely important and can be a great way to get a handle on out-of-control heating and cooling costs. Insulation if fairly easy to install on existing duct work. If you are buying a new duct system, consider one that comes with insulation already installed. Sealing your air ducts to prevent leaks is even more important if you want to save energy and money. If the supply ducts are leaking, large amounts of heated or cooled air can be forced out of holes or unsealed joints and lost. In addition, unconditioned air can be drawn into return ducts through unsealed joints. In the summer, hot attic air can be drawn in, increasing the load on the air conditioner. In the winter, your furnace will have to work longer to keep your house comfortable. Either way, your energy losses can cost you big bucks.

In most cases, air ducts in unconditioned spaces should be sealed and insulated by a qualified HVAC and duct work professional using appropriate sealing and insulation materials -- especially if the air ducts are concealed. If you're a handy do-it-yourselfer, here are a few simple tips to help with minor or temporary repairs to visible duct work.
  • Check your ducts for obvious air leaks. Look for sections of duct work that should be joined but have separated, as well as for holes or punctures.

  • If you use tape to seal your ducts, avoid the common cloth-backed, rubber adhesive duct tape that you can get at any old store. This garden variety duct tape tends to fail quickly. Instead, most HVAC and duct contractors recommend professional quality mastic, butyl, foil or other heat-resistant tapes. Look for tape with the Underwriters Laboratories (UL) logo.

  • Be award that insulating ducts in the basement will make the basement colder. If the heat ducts are fully insulated, water pipes and drains in the basement could freeze and burst if the basement temperature gets too cold. Use electric heating tape wrap on your pipes to prevent this. Also consider insulating your basement walls to hold more heat in or installing heating in your basement.

  • If your basement has been converted to a living area, hire a professional to install both supply and return registers in the basement rooms.

  • Make sure that a well-sealed vapor barrier exists on the outside of the insulation on cooling ducts to prevent moisture from building up.

Related Heating and Air Conditioning Information from Horizon Services...