Does Toronto require duct leakage testing as part of the final HVAC inspection for new construction?

Duct leakage testing is not universally mandated for all new residential construction in Toronto under the Ontario Building Code, but it is required in specific circumstances — and the regulatory landscape is tightening as energy efficiency standards evolve.

The Ontario Building Code (OBC) Part 6 governs mechanical systems including ductwork, and Part 12 governs energy efficiency. For most standard new residential construction in Toronto, the OBC does not currently require a standalone duct leakage pressure test (like a duct blaster test) as a mandatory final inspection step the way some US jurisdictions do under ASHRAE 62.2 or IECC requirements. However, the code does require that all duct joints be mechanically fastened and sealed — meaning leaky ductwork is a code violation even if a formal leakage test is not always performed to verify compliance.

Where duct leakage testing becomes a firm requirement is when a builder is pursuing Energy Star for New Homes certification or Step Code compliance under Ontario's Building Code Energy Performance Compliance path. Ontario's Building Code has incorporated tiered energy performance requirements, and homes targeting higher efficiency tiers must demonstrate whole-building airtightness and duct system performance through testing. The City of Toronto has been progressively pushing new construction toward higher energy performance tiers, and many Toronto builders are now building to Step 3 or Step 4 of the Ontario Building Code Energy Step Code — at these levels, duct leakage testing is effectively part of the compliance pathway.

What the Inspection Actually Covers

During a standard Toronto Building Division mechanical inspection, the inspector visually confirms that ductwork is installed per the approved drawings, that joints appear sealed, that exhaust systems terminate properly, and that make-up air is provided where required. They are not typically running a duct blaster test on every home. What they are checking is that the installation looks correct — proper support, sealed joints, correct materials, fire dampers where required, and exhaust terminations outside the building envelope.

The practical problem is that visual inspection alone cannot detect leakage at concealed joints inside walls, ceilings, or enclosed chases. Studies consistently show that builder-grade duct installations in new homes leak 20-40% of conditioned air before it reaches living spaces — even when joints appear sealed. This is exactly why Aeroseal and professional mastic sealing have become so valuable: they address leakage that visual inspection simply cannot catch.

What This Means for GTA Homeowners in New Construction

If you are buying a new home in Toronto or the GTA, do not assume the ductwork is tight just because it passed inspection. Ask your builder directly whether duct leakage testing was performed, what the measured leakage rate was, and whether the home was built to a specific energy performance tier. Builders targeting Energy Star or Step Code compliance will have this documentation. Builders doing standard OBC minimum compliance may not have tested at all.

For new construction where you have influence over the specifications — a custom build or a major renovation — it is worth specifying duct leakage testing as a contractual requirement. A duct blaster test costs $300-$600 and gives you a measured leakage rate in CFM25 (cubic feet per minute at 25 pascals of pressure). Industry best practice targets total duct leakage below 4 CFM25 per 100 square feet of conditioned floor area. If your new duct system tests above that threshold, the contractor should be sealing it further before the walls close.

Practical tip: If you are moving into a newly built GTA home and have comfort complaints — rooms that are too hot or cold, high energy bills, or humidity issues — duct leakage is one of the first things worth investigating. Aeroseal can seal a leaky new duct system from the inside for $1,500-$3,500 without opening walls, and the energy savings typically recover that cost within 3-5 years in Toronto's climate.

Need help finding a ductwork contractor who can perform duct leakage testing or Aeroseal sealing on your GTA home? Toronto Ductwork can match you with local professionals through the Toronto Construction Network — browse the directory at torontoconstructionnetwork.com/directory?trade=hvac.