At a glance...
Signs of duct problems include uneven temperatures, high energy bills, and dust near vents—even after you've improved insulation
Aerosealing seals leaks from the inside using a non-toxic polymer that sticks to leak edges, closing gaps up to the size of a nickel
The process costs around $2,000-3,000, takes 4-8 hours, and can avoid other more expensive renovations to make rooms comfortable
Ducts are the arteries of your home—they circulate hot and cold air. Like with arteries, leaks and blockages shouldn’t be ignored...but the only time most people think about their ducts is when a scammer calls asking if you'd like them cleaned lately!
Leaky, dirty or blocked ducts can be the culprit behind low energy efficiency in your furnace, A/C, or Heat Pump, as well as poor air quality and uneven temperatures thorough your home. Let's see what you can do about it.
What are some signs that my ducts are dirty, leaky or blocked?
Some spaces still aren’t comfortable even after you’ve improved the insulation and sealed any gaps in your home’s envelope (that’s the roof, walls, windows, doors, and foundation that separate indoors from out).
Your energy costs are much higher than average, and your HVAC equipment has to run constantly to keep your home comfortable.
Rooms far away from furnace are never get warm enough.
You are noticing dust collecting near your air registers or poor air quality even after changing the furnace filter.
Of course, these methods are mostly guesswork. There are tests that Energy Auditors or Duct Technicians can run to get the full story.
A Downtown Toronto Homeowner’s Experience Fixing Up Their Ducts
One of our volunteers hired an Energy Auditor to figure out the heating and cooling issues in her home,
“One of the greatest surprises from my energy audit was being shown that not all the air supply vents of my 1910 house reached the tops of the floors. The auditor also strongly advised me to consider having my ducts Aerosealed [we explain Aerosealing below!], a process with which she herself had had great success in her own home.”
Aerosealing Results
Before getting into what Aerosealing is, let’s review her results:
“The duct sealing reports that were included in the price of my [Aerosealing] service showed that duct leakage in the north half of my house had been reduced by 88%, while leakage in the south half had been reduced by 91%. The result is a more comfortable house and, in one room, a decision not to proceed with an expensive renovation that I thought was needed to make the room more livable in winter. Many other homeowners have told me how amazed they were that this one relatively simple action had so greatly improved the comfort of their home.”
So, What is Aerosealing?
This video from PBS covers it well, but here’s a full explanation of Aerosealing.
Aeroseal is a patented technology that seals duct leaks from the inside out. The process puts escaping air under pressure and causes polymer particles to stick first to the edges of a leak, and then to each other until the leak is completely sealed. Holes up to the size of a nickel can be sealed by Aeroseal.
Aeroseal is guaranteed for 10 years. The sealant used is non-toxic and has been used in hospitals, surgery centers, and government institutions. The primary component is Vinyl Acetate Polymer, used in water-based paints, hair spray, and chewing gum.
Inspection reveals any obvious breaks in the ductwork and, as the initial step of the sealing process, the Aeroseal system determines the exact amount of leakage. According to the Aeroseal Tech website, “many people are surprised to learn that their homes typically leak 30% to 40% or more of their air through air duct leaks.”
What does Aerosealing cost?
When our volunteer had her house Aerosealed at the end of 2021, the cost was $2200 plus HST for up to16 supply vents. The service provider also included air balancing of her HVAC system, repairs to two vents and a long list of checks and improvements included with the Aerosealing package. The cost shouldn’t have changed much since 2021, but you shopping for quotes is always the best way to get a good deal.
Our volunteer recommended homeowners, “Always begin with a pre-treatment assessment and a price estimate, and that way you’ll be able to choose not to proceed if the preliminary inspection shows that your ducts are in pretty good shape.”
What should I expect with Aerosealing?
The entire Aerosealing process takes between 4-8 hours, including protection of furnishings and electronics from overspray, especially on the same floor as the furnace or air handler. It’s good to see your service provider being meticulous and covering everything with tarps.
While not absolutely necessary, occupants, especially pets, may want to be out of the house during the procedure. Aerosealing GTA says that, “a mild odor, like Elmer’s Glue,” lasts for a few hours after sealing. The sealant takes ~2 hours to cure.
To get the most out of Aerosealing, you should probably get your ducts cleaned in advance. A technician can do a pre-treatment assessment of your ducts and make a cleaning recommendation based on their findings.
What other kind of duct improvements should you consider?
Cleaning
Sometimes this will be done before Aerosealing or may be recommended by itself if ducts are dirty but not leaky. When cleaning, compressed air and air agitators are used to clean supply and return duct lines, in conjunction with cleaning inside air vents, and possibly cleaning of the ductwork venting your clothes dryer.
Adjustments
Installation of collars to floor vents up to level with flooring.
Air balancing: larger adjustments of the circulation of your HVAC system so every room in the house receives the right amount of conditioned air (hot or cold, depending on the season).
Adjusting dampers in individual rooms by opening or closing metal diverter fins under supply vents. (You can do this part yourself.)
Upgrades
Resizing your ducts is a larger effort but is often very helpful if you have new additions to your home. In some cases, when switching to a heat pump, larger ducts can improve the system’s performance and longevity. Often just increasing the size of the supply and return trunks (the ducts that connect directly to your furnace/heat pump) is all that’s needed.
At the end of the day, you’re paying for air to be heated or cooled—it’s well worth your time making sure this air reaches you and not the cobwebs inside your walls or unevenly leaking throughout your house!
Do you want to dig deeper?
For more information about duct improvements, you should do an internet search of duct specialists. These contractors should have information about their services and FAQs about their processes.