Insulation and Air Sealing Cost Guide
Insulation is usually priced per square foot of the area covered. Blown-in attic insulation is often the lowest at around one to three dollars a square foot, and spray foam sits higher at two to several dollars depending on the type and thickness. A full attic top-up on an average house often lands in the low thousands.
The price depends on more than the material. Air sealing, removal of old insulation, ventilation work and access all add to the total, and a thin existing layer makes the job larger than a thick one. A quote that lists each area, the material, the target R-value and the extras lets you compare offers fairly.
The ranges below are broad starting points for the current market, not a price list. Regional labour rates, house shape and the depth required in your climate each move the final figure.
Typical price ranges
- Blown-in attic insulation (US)US$1 to US$3 per sq ft
Cellulose or fibreglass blown over the attic floor at typical depth, access not unusually difficult.
- Blown-in attic insulation (Canada)C$1.50 to C$3.50 per sq ft
Complete installation on an average attic in a Canadian metro area.
- Open-cell spray foam (US)US$1 to US$1.75 per sq ft
Installed at moderate thickness in dry, enclosed cavities.
- Closed-cell spray foam (US)US$2 to US$3.50 per sq ft
Installed at a typical thickness for rim joists and basement walls.
- Spray foam, open and closed cell (Canada)C$1.50 to C$5 per sq ft
Open-cell at the low end and closed-cell at the high end, at typical thickness.
- Attic air sealingUS$200 to US$3,500
From a few visible gaps added to an insulation job to a thorough sealing of a leaky attic floor.
- Crawl space insulationUS$2.75 to US$6 per sq ft
Floor area of the crawl space, insulated walls and ground cover, no repairs.
- Old attic insulation removalUS$0.75 to US$2 per sq ft
Standard loose-fill material vacuumed out, with disposal priced separately.
Typical 2025-2026 ranges compiled from published cost guides, including Block Renovation, PickHVAC, HomeStars, HomeWyse, Fixr and contractor guides for spray foam and attic work in the US and Canada. Sources differ, many are contractor-run, and local quotes vary with region, house size and condition, so treat these as broad starting points.
What drives the cost
- Area to be insulated
- Cost rises with square footage, though larger areas cost less per square foot.
- Material and R-value
- A deeper layer or a denser product costs more. Colder regions need a higher target.
- Starting condition
- Wet, matted or contaminated insulation has to come out, which adds removal and disposal.
- Air sealing
- Many gaps or hard-to-reach areas mean more hours.
- Access
- A small hatch, low rafters or a finished attic slow the crew.
- Ventilation work
- Baffles and cleared soffits are small items that protect the roof deck.
- Testing and rebates
- A blower door test adds cost, and some programs require one before and after.
- Season and demand
- Fall and winter often book up quickly, and prices can reflect that.
Ways to keep the cost down
- Do the attic first: it is usually the cheapest place to gain comfort
- Bundle air sealing with insulation in one visit instead of two
- Clear the attic of boxes before the crew arrives to save labour time
- Compare itemized quotes with the same target R-value so the numbers line up
- Check utility and government programs for rebates before you sign, since many require an assessment before the work
Cost questions
How much does it cost to insulate an attic?
Most published guides put blown-in attic insulation at roughly one to three dollars a square foot, so an average house ends up in the low thousands. A thin existing layer, old insulation removal and air sealing push the total higher.
Is spray foam worth the extra money?
For rim joists, basement walls and odd shapes, usually yes, because it seals and insulates in one pass. For a plain attic floor, blown-in insulation costs less for the same R-value.
Why do insulation quotes vary so much?
The scope may differ: R-value, air sealing, removal, baffles and cleanup. Compare line by line, not just the total.
Do rebates still exist?
Programs change often. Some provinces, states and utilities offer incentives for insulation and air sealing, usually with an energy assessment. Check current conditions in your area before you sign.
Get a written price for your job
Fill out the quote form with your city and what you are noticing. A local specialist follows up to look at the attic, walls and basement and give you a written quote. Free to request, no obligation.