Air Sealing, Toronto

Where the air actually moves

Heat leaves a house two ways: conducting through materials, and riding on air that escapes. The second is faster, cheaper to stop, and almost never itemised on an insulation quote.

• Top plates — the gap between the wall framing and the drywall, running the whole perimeter of the ceiling.
• Plumbing stacks and wiring penetrations through the ceiling plane.
• Bath fan housings, which are usually a hole with a fan loosely set in it.
• The attic hatch — the single largest opening in most ceilings.
• Chimney and flue chases, which need non-combustible detailing.
• The rim joist in the basement, where the floor structure sits on the foundation.

When this is the wrong answer

There is a point past which sealing a house needs mechanical ventilation to go with it. In a typical older Toronto house you are nowhere near it, but if your house is already tight and you have condensation on windows in winter, more sealing without ventilation will make that worse rather than better. We will say so rather than sell it.

What it pays

Air sealing pays up to $250 on the assessment pathway. That is not why you do it. You do it because it is the cheapest heat you will ever stop losing.

Amounts are set by Enbridge Gas and Save on Energy and are quoted from the programme pages — attic stream, assessment stream — checked September 2026.

Common questions