Duct sealing to save on heating costs?
October 21, 2005 6:40 AM   Subscribe

Duct sealing to save on heating bills this winter? Has anyone done this, and did it help?

With the high cost of natural gas, we're looking for ways to save money on our heating bills this winter. Our natural gas utility recommends a service called "duct sealing." One product name for this is Aeroseal. Has anyone had their home ducts sealed? What did it cost? If you had it done, did it help save on your heating bills? Did you save the cost of the "treatment"? How often does it have to be done?
posted by Joleta to Home & Garden (14 answers total)
If your ducts leak, they should be sealed up, because they're losing heat to places outside the living space. They should be insulated for the same reason. That said, I have no knowledge of the procedure or product the utility is touting.
posted by Kirth Gerson at 6:53 AM on October 21, 2005

I've done this with my ducts. I used some reasonably-cheap aluminum foil tape (about $4CDN per roll at Rona/Home Depot) and sealed all the accessible joints in the basement. I'm not sure it's saved much money, but it has increased the airflow to the upper floors, making things more comfortable. No sense having warm air leaking into the basement where it doesn't need to be kept warm, only above freezing.

One note: Do not use standard "duck tape" on heating ducts. Duck tape works well on many things, but ironically ducts aren't one of them.
posted by gwenzel at 7:09 AM on October 21, 2005

This procedure (spray lining the inside of the ducts) was used where I work. Workers in that building complained of a heavy latex paint type odor, and some had runny noses and watery eyes. YMMV.
posted by fixedgear at 7:21 AM on October 21, 2005

It does sound like a rather unnecessarily messy procedure. Pick up a roll of duct (not duck) tape, the silver foil kind that gwenzel mentioned, and just take an afternoon to do it yourself.
posted by odinsdream at 7:28 AM on October 21, 2005

We did it ourselves, with the foil faced thermal tape from the local Home Despot, and reduced heat leakage substantially. Took an afternoon.

Turn on your heat and grab a piece of toilet paper about 2 sheets long or a tissue. With the air going, get into your "crawlspace" or attic where the ducts run. Hold the tissue at the very edge with your thumb and forefinger. At every joint, drape the tissue alongside of the duct and watch it to see if leaking air makes the tissue move. If it does, you have an airleak. Use foil faced tape to seal up the joint and move on to the next one.

Cheap. Efficient. Easy.
posted by jeanmari at 7:43 AM on October 21, 2005

Of course, the benefit of the duct lining process is that it stops all the leaks (in theory) not just the ones in the basement, where you can access the duct from below. But a cost/benefit analysis (including the latex smell, cost, etc) may demonstrate that it's not worth it.

At the same time, the quality of the ductwork (WRT joint tightness) that you see in the basement is probably representative of the fit and finish of the work within the walls, so if you are horrified by the amount of energy leaking into your basement, you might want to consider more "advanced" options.

The problem is that the return on this stuff is usually soo long, like insulating an existing house. the payback for the investment can be quite long. So you are probably best off spending the least money for the most return, i.e. taping the ducts in the basement.
posted by misterbrandt at 8:20 AM on October 21, 2005

Google find: Duct tape not for ducts?
posted by jikel_morten at 8:27 AM on October 21, 2005


You may also want to look into having the ducts cleaned if they haven't been done recently and installing a humidifier to your furnace. My husband and I did both last year--the duct cleaning took place in the spring so I don't know how it affected the heating bill but the humidifier made a huge difference. Huge in the sense that we felt warmer in the house with the thermostat set lower.

Added benefits--I didn't wake up with a dry, scratchy throat every morning with the furnace on, my skin didn't dry out as much and our poor cats didn't suffer from static cling.

The cost to install was in the neighborhood of $400-500. Vent cleaning was about $100. Obviously, it wouldn't be worth doing either unless you plan on sticking around in your home for awhile to come.
posted by Sully6 at 9:11 AM on October 21, 2005

Sully6: We put in a humidifier as soon as we bought the house. We're the original owners, and the house is five years old. How often should ducts be cleaned? The Aeroseal guys do the duct cleaning as well.
posted by Joleta at 10:25 AM on October 21, 2005

Joleta: duct cleaning? every 5 years or so - hope you had them cleaned out just after moving in, with new homes there can be a fair amount of construction dust in the ducts.

Hell - I've even seen guys sweeping sawdust into open vents prior to finishing a house...
posted by jkaczor at 10:41 AM on October 21, 2005

I hired Brouwer Brothers. The techs who came to do the job thought cleaning the ducts every 3-5 years was sufficient. I guess it just depends on the shape your ducts are in, although I'm sure if you ask Aeroseal, they'll tell you do it.

Our house is about 100 years old, from the looks of it, our ducts had never been cleaned. (I actually would not have thought to do it, except our realtor suggested it.)

When Brouwer Brothers came out, they inserted a camera into the ducts, took a picture and then showed it to me. There were several inches of dust and debris accumulated on our duct walls--it was pretty nasty. What's more, there were two garbage bags' worth of trash in the ductwork--stuff like broken glasses, construction material and rocks. Sadly, no diamond necklaces though!

There is a National Air Duct Cleaner Association, weirdly enough, and they vaguely tout the benefit of energy savings with duct cleaning on their site. That said, since you have a newer house, it may not have much impact on how efficiently your HVAC system operates.
posted by Sully6 at 11:00 AM on October 21, 2005

What type of humidier is best?

I'm on continual air-circ if that makes a difference.
posted by five fresh fish at 11:10 AM on October 21, 2005

five fresh fish, Are you looking for a recommendation for a humidifier that mounts to your furnace or a plug-in model that you can place in a room? I had the former installed. The brand is Aprilaire, which seems to be the standard among the HVAC service companies I called.

If it's the later you're after, check out the reviews over at Consumer Search.
posted by Sully6 at 11:41 AM on October 21, 2005

It'd be a furnace-mount. With the spiffy new Lennox super-high-efficiency furnace came a spiffy new DC-driven variable-speed motor that works best when it's left always-on. It evens out the temperature differentials between the bottom and top floors, keeps the air cleaner by having it continually passing through the HEPA filter, and uses less electricity than the old AC start/stop types.
posted by five fresh fish at 6:15 PM on October 21, 2005

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