Condo Blues: Save Some Bucks – How to Seal Heating Ducts!

Thursday, October 2, 2008

Save Some Bucks – How to Seal Heating Ducts!

I am on a mission to seek out and destroy air leaks in The Condo so I can save money on my heating and cooling bills this year. According to it will be worth it too:
“EPA estimates that homeowners can typically save up to 20% of heating and cooling costs (or up to 10% of total energy costs) by air sealing their homes
and adding insulation in attics, floors over crawl spaces, and accessible basement rim joists.”

One place to look for air leaks is in the heating and air-conditioning (also known as HVAC) ducts in your home (or Condo.) Air leaks make your HVAC system use more fuel and work harder to do the job it’s supposed to do. And that can cost you money. Especially if those air leaks are in the unheated/uncooled areas of your home such as a basement, or in my case, in an unheated utility room.

There are generally two places where air leaks occur and that you need to seal:

  • The area where two pieces of air duct are connected together
  • The area in the wall where the ductwork meets/goes into the wall
This is a very cheap and easy project that even a novice handy gal (or guy) can do. If you can cut and stick a piece of tape and squirt a can of shaving cream, then you are more than qualified to do this project.

How to Seal Connections in HVAC Ducts the Easy Way

MaterialsRoll of metal/aluminum tape (also called Sheating tape)
A ladder (optional)

Do It
Most the leaks in air ducts will occur where two pieces of the air duct are joined together. The quickest and easiest way to ensure that air isn’t leaking from the joint is to cut a long piece of metal tape, climb a ladder (if need be), and wrap the tape around the area where two pieces of ductwork meet. Smooth down the edges of the tape around the duct joint, and ta da! You’ve just sealed an air leak in an air duct connection!


Traditional duct tape has a thousand and one uses; unfortunately sealing ducts isn’t one of them. Cloth or plastic duct tape will loosen over time and you’ll have to keep retaping your ducts. Save yourself some trouble, spend a little extra money (I think it cost me only a couple of dollars more to buy metal tape than it would to buy regular duct tape) and buy the metal tape.

Mind the Gap: How to Seal Gaps between HVAC Ducts and Walls the Easy Way

Can of expanding spray foam insulation (for large gaps) or tube of caulk (for small gaps)
A ladder (optional)
Do It
If there is a gap between where your air duct meets the wall, climb a ladder (if need be), put the tip of can of the spray foam/caulk gun into the crack, pull the trigger to fill the gap with spray foam or caulk. Ta Da - you’ve just sealed a leak in an air duct!

Make sure you use spray foam in a well-ventilated place, otherwise, it may be best to use caulk for this project. After 24 hours, the spray foam will be hard enough for you to trim with a saw like in the video. I didn’t bother with that since I was sealing ducts in my utility room and no one but me, Husband, and possibly Blitzkrieg would see it.
Depending upon the brand and amount of spray foam that you use, this project can get a little messy. I recommend wearing old clothes and a pair of gloves. I didn’t wear gloves the last time I used spray foam and spent a week trying to wash dried spray foam off my hands with all sorts of soap, water, and ended up scrubbing it off my hands with a pumice stone. Did I mention that I had to scrub my hands raw in order to get the stuff off my hands? Ow. I would have saved myself a lot of trouble if I donned a pair of gardening gloves before I started my project.

Summer or early fall is the perfect time to seal your heating and cooling ductwork if not for one simple reason: You won’t singe your fingers on the outside of the heating ducts because the furnace is off and the outside of the heating and air conditioning air ducts are cool to the touch.

Trust me on this one. I know of where I speak.