Spray foam insulation costs $2.50–$4.00/sqft installed in the GTA. Fiberglass batt runs $0.80–$1.50/sqft. That gap looks decisive — until you factor in settling, air leakage, lifespan, and moisture risk. Here’s the complete breakdown GTA homeowners need before committing to either product.
Spray Foam vs Fiberglass Batt Insulation: Which Is Right for Your GTA Home?
Both materials insulate. Both qualify for Canada Greener Homes rebates. But they perform completely differently in Ontario’s climate — and the wrong choice for your attic or basement can cost you far more than the upfront price difference.
Fiberglass batt is the familiar pink or yellow roll sold at every hardware store. It’s installed between studs and joists, it doesn’t bond to framing, and it relies on an additional air barrier (house wrap, poly vapour barrier) to actually seal your envelope. Spray foam, applied as a liquid that expands and hardens, is simultaneously insulation and air barrier. That dual function is why GTA contractors see it outperform batt in cold-climate heating costs year after year.
The right choice depends on: application (attic rafter vs wall cavity vs below-grade), budget, how long you plan to stay in the home, and whether you’re targeting Ontario energy rebates. Work through each section below and the answer will be clear.
Cost Comparison: Spray Foam vs Fiberglass Batt per Square Foot
All prices are installed costs in the GTA (Toronto, Scarborough, North York, Etobicoke, Vaughan, Mississauga, Markham, Brampton). Material-only costs excluded.
| Application | Open-Cell Spray Foam | Closed-Cell Spray Foam | Fiberglass Batt |
|---|---|---|---|
| Attic (rafter cavity) | $1.50–$2.50/sqft | $2.50–$4.00/sqft | $0.80–$1.20/sqft |
| Basement walls / rim joist | $1.75–$3.00/sqft | $2.75–$4.50/sqft | Not recommended (moisture risk) |
| Exterior wall cavity | $1.50–$2.50/sqft | $2.50–$4.00/sqft | $0.80–$1.50/sqft |
| Crawl space | $1.75–$3.00/sqft | $3.00–$5.00/sqft | Not recommended (moisture risk) |
| Rim joist only | $1.50–$2.25/sqft | $2.50–$3.75/sqft | $0.60–$1.00/sqft (air-sealed separately) |
Typical whole-attic project in a 1,500 sqft GTA semi-detached:
- Open-cell spray foam: $2,250–$3,750
- Closed-cell spray foam: $3,750–$6,000
- Fiberglass batt (materials + labour): $1,200–$1,800
That $1,000–$4,000 upfront gap is real. Whether it’s worth paying depends on what happens over the next 10–30 years — covered in the payback section below.
For a full application-by-application cost breakdown, see our spray foam insulation services page.
R-Value Comparison: Spray Foam vs Fiberglass Batt (Per-Inch & Effective)
R-value measures thermal resistance per inch of material. Higher is better — but the installed effective R-value matters more than the label on the bag.
| Material | R-Value per Inch | R-Value After 10 Years | Air Seal Included? | Notes |
|---|---|---|---|---|
| Open-cell spray foam | R-3.7 | R-3.7 (stable) | Yes | Vapour-open; preferred for attic with drainage plane |
| Closed-cell spray foam | R-6.0 | R-6.0 (stable) | Yes | Class II vapour retarder; mandatory below grade |
| Fiberglass batt (standard) | R-3.2–R-3.8 | R-2.6–R-3.4 (settles 10–20%) | No (requires separate barrier) | Compression or gaps reduce stated R-value immediately |
| Cellulose (blown-in, for reference) | R-3.2–R-3.8 | R-2.9–R-3.4 (settles 5–15%) | No | Comparable settling risk; see our cellulose comparison article |
A 2×6 wall framed at 5.5″ gives you a theoretical R-21 with fiberglass batt — if the batt is perfectly fitted, uncompressed, and the cavity is fully air-tight. Real-world installs in GTA homes routinely fall short of that. Any gap, compression, or thermal bridge through the stud frame erodes effective R-value by 20–40%.
Spray foam fills every corner of the cavity by design. There are no voids, no compression, no thermal bypass. That’s why a 3″ closed-cell spray foam wall (R-18 nominal) often outperforms a 5.5″ batt wall in measured energy performance. For a deeper look at the open-cell vs closed-cell decision, visit our open-cell spray foam and closed-cell spray foam pages.
The Hidden Cost of Settling: Why Fiberglass Batt Loses R-Value Over Time
This is the number GTA homeowners almost never hear from the big-box stores: fiberglass batt insulation settles 10–20% in thickness over 10 years. That’s not a fringe estimate — it’s documented in building science literature and confirmed in attic inspections on homes across Toronto, Mississauga, Vaughan, and Markham.
Here’s what settling costs in practice:
- A freshly installed R-22 batt attic (6″ of R-3.7/inch batt) settles to roughly R-17.6–R-19.8 within a decade — potentially falling below Ontario Building Code requirements for attic insulation.
- Topping up with additional batts costs $0.60–$1.20/sqft in materials and labour — on a 1,500 sqft attic, that’s $900–$1,800 in remediation at the 10-year mark.
- If you don’t top up, you’re heating a home with sub-code insulation — in a Toronto winter that averages 4,000–4,500 heating degree days, that efficiency gap compounds every year you leave it unaddressed.
Spray foam — open-cell or closed-cell — does not settle. It bonds chemically to the substrate (wood, concrete, masonry) and maintains its installed R-value for the lifetime of the building. We’ve inspected homes in Etobicoke and Scarborough where spray foam applied 15+ years ago is still at original thickness and performing as specified.
Real-cost comparison after 20 years (1,500 sqft attic):
- Fiberglass batt: $1,200–$1,800 install + $900–$1,800 top-up at year 10 = $2,100–$3,600 total
- Open-cell spray foam: $2,250–$3,750 install, $0 remediation = $2,250–$3,750 total
The 20-year raw cost difference narrows to near-parity — and that’s before counting the energy savings spray foam delivers every year.
Air Sealing: Spray Foam Wins on Continuous Seal vs Batt Gaps & Energy Loss
Insulation only works if air can’t bypass it. Fiberglass batt is not an air barrier. It’s a thermal barrier that must be paired with a polyethylene vapour barrier, house wrap, and caulked penetrations to stop convective heat loss. In a typical GTA home renovation or attic upgrade, this secondary air sealing step is often done poorly — or skipped entirely.
Research from the Building Science Corporation and NRC Canada shows that air leakage accounts for 25–40% of heating energy loss in older Ontario homes. A 10% air leakage rate through gaps around batt insulation can reduce effective R-value by 30% — meaning your R-22 attic performs closer to R-15 in real-world conditions.
Spray foam eliminates this completely. The foam adheres to every surface and self-seals penetrations, electrical boxes, and framing irregularities that batts leave open. Post-spray blower door results in GTA installations consistently measure 1.5–3.0 ACH50 — well below the OBC target of 3.5 ACH50 for new construction.
GTA winter heating-loss scenario (Toronto, January average -6.8°C):
- Home with R-22 fiberglass batt + typical air sealing: estimated $2,400–$3,200/year in natural gas heating
- Same home re-insulated with open-cell spray foam (R-22 attic + rim joist seal): estimated $1,600–$2,200/year — a $800–$1,000/year reduction
- Payback on the spray foam upgrade at current Ontario gas rates: 3–5 years
For a deeper look at attic vs basement spray foam applications and where each dollar of insulation investment goes furthest, see our attic vs basement cost and application guide.
Moisture Control: When Spray Foam Wins (& When Batt Works)
Moisture is the silent insulation killer in Ontario. GTA basements deal with hydrostatic pressure from spring thaw, summer humidity, and temperature swings that cycle condensation through wall assemblies. Here’s how each material handles it by application:
| Location | Spray Foam (Closed-Cell) | Spray Foam (Open-Cell) | Fiberglass Batt |
|---|---|---|---|
| Attic (ventilated) | Works — vapour barrier function | Preferred — allows drying to interior | Works — if ventilation is adequate |
| Attic (unventilated / conditioned) | Best — complete envelope seal | Acceptable with careful design | Poor — no air seal, moisture accumulates |
| Basement walls (above grade) | Best — moisture barrier + insulation | Acceptable — monitor interior humidity | Acceptable with proper vapour barrier |
| Basement walls (below grade) | Required — only code-correct option | Not recommended below dew point | Not suitable — absorbs moisture, mold risk |
| Rim joist | Best — seals + vapour control | Good — seals air leakage | Poor — compresses, gaps remain |
| Crawl space | Best — seals ground vapour | Not recommended | Not suitable — moisture wicking guaranteed |
The basement rule is absolute: Fiberglass batt installed against below-grade concrete will absorb moisture from the concrete face regardless of a poly vapour barrier. We’ve removed soaked, mold-contaminated batt from GTA basements in Brampton, Mississauga, and North York where it was installed only 3–5 years prior. Closed-cell spray foam is the correct solution below grade — it provides R-6/inch plus Class II vapour retarder in one application.
For basement-specific guidance, visit our basement insulation service page.
Payback Analysis: Spray Foam vs Fiberglass Batt Over 20–30 Years
Let’s run the complete 30-year cost model for a typical GTA semi-detached (1,500 sqft attic + rim joist):
| Cost Factor | Fiberglass Batt | Open-Cell Spray Foam | Closed-Cell Spray Foam |
|---|---|---|---|
| Initial install | $1,200–$1,800 | $2,250–$3,750 | $3,750–$6,000 |
| Year-10 remediation (settling top-up) | $900–$1,800 | $0 | $0 |
| Year-20 re-insulate (end of lifespan) | $1,200–$1,800 | $0 | $0 |
| Annual heating savings vs batt (est.) | Baseline | $800–$1,000/yr | $1,000–$1,200/yr |
| 30-year energy savings | — | $24,000–$30,000 | $30,000–$36,000 |
| 30-year net cost | $3,300–$5,400 + energy cost gap | $2,250–$3,750 (install only) | $3,750–$6,000 (install only) |
| Canada Greener Homes rebate eligibility | Up to $5,600 (if ≥R-22 achieved at audit) | Up to $5,600 (stable R-value = audit-certain) | Up to $5,600 (stable R-value = audit-certain) |
After rebates and energy savings, spray foam reaches cost parity with batt within 4–7 years in most GTA applications. If you plan to stay in your home 10+ years, the case for spray foam is difficult to argue against on a numbers basis alone.
For a comparison against blown-in insulation, see our spray foam vs blown-in insulation guide.
OBC SB-12 Compliance: Code-Approved Installation Paths
Ontario Building Code Supplementary Standard SB-12 sets minimum effective thermal resistance for new construction and major retrofits. Both spray foam and fiberglass batt can achieve code compliance — but the margin for error is very different between them.
SB-12 minimum R-values (Ontario Climate Zone 6 — GTA and most of southern Ontario):
- Attic: R-31 to R-60 (depends on compliance path selected)
- Walls: R-22 to R-24 effective
- Below-grade walls: R-17 to R-24
Spray foam compliance path:
- 4″ closed-cell in rafter cavity = R-24 ✓ (meets R-22 wall minimum cleanly)
- 5.5″ open-cell in attic joist cavity = R-20.4 (may require supplemental blown-in on attic floor)
- 6″ closed-cell on below-grade wall = R-36 ✓ (exceeds all below-grade requirements)
- Spray foam is measured and consistent — no settling risk between install date and inspection
Fiberglass batt compliance path:
- 5.5″ R-22 batt in 2×6 wall = R-22 nominal, R-16–R-18 effective (thermal bridging through studs reduces real-world value)
- Achieving SB-12 effective R-22 with batt typically requires adding continuous exterior rigid foam — which eliminates most of the cost advantage
- Settling after inspection can bring attic batts below code without triggering a re-inspection — a compliance risk that persists silently
For builders and homeowners doing permitted renovations in Toronto, Vaughan, Markham, or Mississauga, spray foam’s consistent measured thickness simplifies the inspector sign-off. We provide thickness documentation and R-value certificates on every install. See our attic insulation service page for application specifics.
Ontario Rebates: What Both Materials Qualify For
Both spray foam and fiberglass batt can qualify for the Canada Greener Homes Grant (up to $10,600 CAD) and Ontario IESO programs — as long as minimum R-values are achieved and maintained at EnerGuide audit time.
- Attic insulation rebate: Up to $5,600 for upgrading to ≥R-60 (attic) or ≥R-22 (roof assembly). Spray foam’s stable R-value means your post-retrofit audit reading matches your install measurement. Fiberglass batt settling may reduce measured R-value below the rebate threshold between install and audit, risking a lower tier payout.
- Wall insulation rebate: Up to $1,250 for achieving ≥R-12 effective. Closed-cell spray foam (2″ = R-12) hits this target cleanly with no dependency on air barrier continuity.
- Enbridge HER+ rebates: Up to $2,500 for natural gas customers meeting prescriptive R-value thresholds. Spray foam’s continuous air seal also improves blower door score — some customers qualify for additional air sealing rebates simultaneously.
A pre- and post-retrofit EnerGuide audit is required for Greener Homes. We coordinate with certified energy advisors across Toronto, Scarborough, North York, Etobicoke, Vaughan, Mississauga, Markham, and Brampton. Full rebate details at our Ontario rebates guide.
Why Choose Spray Foam Kings for Your GTA Insulation Project?
We are spray-foam specialists, not generalists. Here’s what that means for your project:
- SPFA Certified installers — not general contractors who sub out insulation work
- $5M liability insurance + WSIB — fully covered on every GTA job, no exceptions
- 15+ years of GTA installations — we’ve insulated hundreds of Toronto-area homes and know the building stock (1960s semi-detached, 1980s split-levels, 2000s tract homes) inside out
- OBC SB-12 documentation — thickness certificates and R-value records provided on every job for permit and rebate purposes
- Rebate coordination — we work alongside EnerGuide auditors to maximize Canada Greener Homes Grant recovery for our customers
- Honest product guidance — we’ll tell you when open-cell is the right call (attic, wall cavities) vs closed-cell (below-grade, rim joist), and we won’t push the higher-margin product when it’s not warranted
“We had quotes from three contractors. Spray Foam Kings was the only one who explained why fiberglass batt wasn’t going to work in our basement, showed us the moisture data, and gave us an honest payback timeline. The closed-cell install was done in one day. Our basement went from unusable to finished living space within 6 months.”
— Michelle T., Mississauga homeowner, basement + rim joist closed-cell project
Get Your Free Quote Today
Call: 647-641-6881
We’ll assess your specific application — attic, basement, wall cavity, or rim joist — give you a firm CAD/sqft quote, and identify which Ontario rebate programs apply to your project. No obligation, no pressure on product type. Serving Toronto, Scarborough, North York, Etobicoke, Vaughan, Mississauga, Markham, and Brampton.
Frequently Asked Questions (Homeowner-Specific)
What is the upfront cost difference between spray foam and fiberglass batt insulation in the GTA?
Spray foam (open-cell) runs $1.50–$3.00/sqft installed vs fiberglass batt at $0.80–$1.50/sqft. For a typical 1,500 sqft GTA attic, that’s $2,250–$4,500 for spray foam vs $1,200–$2,250 for batt — a gap of roughly $1,000–$2,000 upfront. That gap closes significantly when you account for settling remediation at year 10 ($900–$1,800 for batt), energy savings of $800–$1,000/year for spray foam, and rebate recovery of up to $5,600 through Canada Greener Homes.
Does fiberglass batt insulation really settle over time?
Yes. Fiberglass batt loses 10–20% of installed thickness over 10 years due to gravity compression, humidity cycling, and loss of loft. An R-22 batt attic can settle to R-17.6–R-19.8 over a decade — potentially falling below Ontario Building Code minimums without triggering any re-inspection. Spray foam bonds chemically to the substrate and retains its installed R-value for the life of the building. It does not settle.
How much energy does settling fiberglass batt lose in a GTA home?
A 15% R-value reduction in an attic with a $2,400/year heating bill adds roughly $360–$480/year in extra heating costs. Over 10 years, that compounds to $3,600–$4,800 in energy loss — before accounting for additional air leakage through batt gaps around joists, pipes, and electrical penetrations. Spray foam’s continuous air seal eliminates both the settling loss and the convective bypass simultaneously.
Which insulation is better for attics: spray foam or fiberglass batt?
It depends on the attic configuration. For a ventilated attic floor (insulation on the floor joists, attic stays cold), blown-in options can compete on price — though spray foam still wins on air sealing. For rafter-cavity insulation (conditioned attic, or future bonus room conversion), spray foam is the definitive correct call. It stays in place permanently, seals the roof deck, and doesn’t require removal if the attic is converted to living space. Fiberglass batt in rafter cavities must be removed entirely for attic conversion, adding $1,500–$3,000 in removal costs at conversion time.
Can I use fiberglass batt insulation in my GTA basement?
No — not against below-grade concrete. Fiberglass batt is hydrophilic and has no vapour retarder function. Against below-grade concrete walls, moisture migrates from the concrete face into the batt and creates conditions for mold growth within 2–5 years, regardless of a poly vapour barrier installed in front of it. Ontario Building Code and building science best practice require a vapour-control layer directly against below-grade concrete. Closed-cell spray foam provides R-6/inch plus Class II vapour retarder in one application — the correct solution for GTA basements.
How long does each insulation type last?
Spray foam (open-cell or closed-cell) has a design lifespan of 30+ years with no degradation in R-value when properly installed and left undisturbed. Fiberglass batt typically performs adequately for 10–20 years, with recommended top-up or replacement at the 10-year mark to maintain original R-value and code compliance. Batt that gets wet — from a roof leak, flood, or chronic moisture — requires immediate replacement and mold inspection.
Which insulation qualifies for the Canada Greener Homes Grant?
Both qualify — but spray foam has a practical audit advantage. The Greener Homes Grant pays up to $5,600 for attic insulation when you achieve the required post-retrofit R-value (typically ≥R-40 for attic top-up). Spray foam’s stable, measured R-value means your EnerGuide audit result matches your install. With fiberglass batt, settling between install date and audit date can reduce the measured R-value below the threshold, risking a lower rebate tier. We coordinate with certified energy advisors in Toronto, Mississauga, Vaughan, and across the GTA to document installs for maximum rebate recovery.
Is spray foam insulation worth the extra cost for a GTA homeowner?
For basements, rim joists, and rafter-cavity attics: yes, categorically. The moisture risk of fiberglass batt below grade makes spray foam not just a cost preference but a functional requirement. For attic floor joist applications, spray foam wins on performance and longevity, but batt can be cost-competitive if you plan to sell within 5 years. For homeowners staying 10+ years in the GTA, spray foam’s 30-year lifespan and energy savings consistently deliver superior total cost of ownership at the 4–7 year payback mark.
What is the payback period for spray foam insulation vs fiberglass batt in Toronto?
The net cost premium of open-cell spray foam over fiberglass batt on a 1,500 sqft attic is approximately $1,000–$2,000 after Canada Greener Homes rebates. At $800–$1,000/year in documented energy savings, the net-of-rebates payback period is 1–2.5 years, or 3–5 years at full pre-rebate cost. Closed-cell spray foam has a longer payback of 4–7 years at full cost but eliminates all moisture and settling risk — particularly critical for below-grade applications.
How much can I save on heating over 20 years with spray foam vs fiberglass batt?
A well-sealed GTA home with open-cell spray foam (attic + rim joist) typically saves $800–$1,000/year in natural gas heating vs an equivalent fiberglass batt install, based on 4,000–4,500 heating degree days in Toronto and current gas rates (~$0.35/m³). Over 20 years, that’s $16,000–$20,000 in cumulative savings. Add zero remediation cost vs $1,800–$3,600 for batt settling and eventual replacement, and the 20-year total advantage of spray foam is typically $17,000–$24,000 on a standard GTA semi-detached.