If some rooms in your Newmarket home never get enough air, or you’re living with uneven room temperatures between floors, leaky ducts are a common cause. Leaks in hidden duct runs let heated or cooled air escape before it reaches your rooms, so the furnace or AC runs longer and the house still doesn’t feel right.
We measure your duct leakage, fix the accessible gaps by hand, seal the rest from the inside with Aeroseal, then measure again. You keep the Aeroseal Seal Certificate with both numbers on it.
We recently sealed the ducts in a home in Newmarket. Before sealing, the duct leakage measured 49.5%. After sealing, it measured 2.2%.
In plain words: most of the air that was escaping through leaks in the ductwork now reaches the rooms instead. The leakage left is less than a twentieth of where it started, and the homeowner noticed much stronger airflow afterwards.
We also found air escaping around supply registers that hadn’t been installed tightly. The register boots weren’t sealed to the openings in the floor and ceiling, so some air was leaking around the registers instead of coming out of them. We sealed those boots by hand.
These are measured numbers, not estimates. We test before we start and again after sealing, and every Aeroseal job ends with a Seal Certificate showing both. We never share our customers’ addresses.


All of Newmarket, including Stonehaven, Glenway, Summerhill, Woodland Hill, Armitage, Copper Hills, Huron Heights, Bristol-London and the older streets around Main Street.
Nearby York Region towns too: Aurora, East Gwillimbury (including Holland Landing, Sharon and Queensville), King and Richmond Hill.
Newmarket has everything from older houses near downtown to newer subdivisions. A few things we look for, generally speaking:
Most homes take about 4 hours for sealing, or about 6 hours with air balancing. See the full process →
Aeroseal seals gaps up to about 5/8 inch. Bigger holes and disconnected ducts get repaired by hand first, and we’ll tell you before doing any extra work. It’s not duct cleaning, and it won’t make an undersized furnace or AC bigger. If the test shows sealing won’t help much, we’ll say so.
All registers in the home included.
Also included: the leakage test before and after, hand-sealing of accessible gaps, Aeroseal sealing and your Seal Certificate. Repairs to disconnected ducts or large gaps are quoted before we do them. See all services and prices →
No. Cleaning removes dust. Aeroseal seals leaks so more heated or cooled air reaches your rooms.
It’s the metal piece that connects a duct to the register opening in your floor, wall or ceiling. If it isn’t sealed to the opening, some of the air leaks into the floor or ceiling instead of coming out into the room. We check for this and seal boots by hand where we can reach them.
We measure your leakage before and after sealing. Both numbers are on your Aeroseal Seal Certificate, and you keep a copy.
Most homes take about 4 hours for sealing, or about 6 with air balancing. Someone needs to let us in and be around at the start and the end. We ask that as few people as possible stay in the house while the sealing runs.
Yes. We’re based in Mississauga and we come up to Newmarket regularly. We work Monday to Saturday, 8 am to 6 pm. Call 647-218-8031 for the next opening.
Call or text 647-218-8031, Monday to Saturday, 8 am to 6 pm. Or send us your postal code and what’s going on, and we’ll call you back with a price.
Also serving: Mississauga · Brampton · Oakville · Milton · Innisfil · Orillia · All service areas