Spray Foam vs Fiberglass Insulation in Toronto
Published February 20, 2026 • By Unique Fireproofing
Choosing between spray foam and fiberglass insulation is one of the most important decisions Toronto homeowners face during renovations or new construction. Both materials have their place, but the differences in performance, cost, and longevity are significant — especially in Ontario's demanding four-season climate with winter temperatures dropping below minus 25 degrees Celsius and summer humidity pushing past 80 percent.
R-Value Comparison
R-value measures a material's resistance to heat flow. The higher the R-value per inch, the better the insulation performs. Here is how spray foam and fiberglass compare:
| Property | Closed-Cell Spray Foam | Open-Cell Spray Foam | Fiberglass Batt |
|---|---|---|---|
| R-Value per Inch | R-6.0 to R-7.0 | R-3.6 to R-3.8 | R-3.1 to R-3.4 |
| 2x4 Wall (3.5") | R-21 to R-24.5 | R-12.6 to R-13.3 | R-12 |
| 2x6 Wall (5.5") | R-33 to R-38.5 | R-19.8 to R-20.9 | R-19 to R-20 |
| Air Barrier | Yes | Yes (at 3.5"+) | No |
| Vapour Barrier | Yes (at 2") | No | No |
| Moisture Resistant | Excellent | Moderate | Poor |
Cost Comparison for Toronto Homes
Cost is often the primary factor for homeowners. Here is a realistic breakdown of installed costs in the Greater Toronto Area for 2026:
| Material | Cost per Sq Ft (Installed) | 1,000 Sq Ft Project |
|---|---|---|
| Closed-Cell Spray Foam (2") | $2.50 – $4.00 | $2,500 – $4,000 |
| Open-Cell Spray Foam (3.5") | $1.50 – $2.50 | $1,500 – $2,500 |
| Fiberglass Batt (R-20) | $0.80 – $1.50 | $800 – $1,500 |
While fiberglass is significantly cheaper upfront, the total cost of ownership tells a different story. Spray foam's superior air sealing typically reduces heating and cooling costs by 30 to 50 percent compared to fiberglass. For a Toronto home spending $3,000 per year on energy, that translates to $900 to $1,500 in annual savings. Over a 10-year period, spray foam often pays for itself through reduced energy bills alone.
Performance in Toronto's Climate
Toronto sits in Climate Zone 6 under the Ontario Building Code, which demands high insulation standards. Our winters bring sustained temperatures of minus 15 to minus 25 degrees Celsius, and summer humidity regularly exceeds 70 percent. This combination creates unique challenges for insulation materials.
Fiberglass performance degrades in real-world conditions. The R-values printed on fiberglass packaging are measured in laboratory settings with no air movement. In actual Toronto attics and walls, wind-washing, air leakage, and convection currents can reduce fiberglass's effective R-value by 20 to 40 percent. When fiberglass gets damp from condensation — common in Toronto basements — it can lose up to 40 percent of its insulating value.
Spray foam maintains its rated R-value consistently because it bonds directly to surfaces, eliminates air gaps, and does not absorb moisture. Closed-cell spray foam actually adds structural rigidity to walls and resists water completely, making it ideal for Toronto basements where moisture intrusion is the number one concern for homeowners.
Air Sealing: The Critical Advantage
Air leakage accounts for up to 40 percent of a Toronto home's energy loss. Fiberglass batts provide zero air sealing — they are permeable to air by design. Installing fiberglass requires a separate air barrier (typically polyethylene sheet or housewrap), and any gaps, tears, or imperfect sealing at penetrations allow air to bypass the insulation entirely.
Spray foam is both insulation and air barrier in a single application. It expands to fill every crack, gap, and penetration, creating a continuous air seal that dramatically reduces energy loss. For Toronto homeowners dealing with drafty older homes, this air sealing capability is often more valuable than the insulation itself.
Moisture Resistance
Toronto's freeze-thaw cycles and high humidity make moisture management critical. Fiberglass absorbs water readily and provides an ideal environment for mold growth when damp. Wet fiberglass in basements is one of the most common insulation failures we see in Toronto homes.
Closed-cell spray foam has a water absorption rate of less than 2 percent by volume and actively resists moisture penetration. It does not support mold growth, even in high-humidity environments. For Toronto basements, crawl spaces, and rim joists, closed-cell spray foam is the clear winner for moisture protection.
Longevity and Maintenance
Fiberglass batts have a practical lifespan of 15 to 25 years before they begin to sag, compress, and lose effectiveness. Many Toronto attics insulated with fiberglass in the 1990s are already performing well below code requirements.
Spray foam insulation lasts the lifetime of the building — 80 years or more. It does not sag, settle, or degrade. Unique Fireproofing provides a 25-year thermal performance warranty on all spray foam installations, but the material itself will outlast the warranty by decades.
When to Choose Each Insulation Type
Choose Spray Foam When:
- ✓ Insulating basements or crawl spaces
- ✓ Air sealing is a priority (drafty homes)
- ✓ Moisture resistance is needed
- ✓ Maximizing R-value in limited space
- ✓ Long-term value matters more than upfront cost
- ✓ You plan to stay in the home long-term
Consider Fiberglass When:
- • Budget is the primary constraint
- • Insulating a dry attic with proper ventilation
- • DIY installation is planned (spray foam requires professionals)
- • The area is easily accessible for future replacement
Our Verdict for Toronto Homeowners
For the vast majority of Toronto insulation projects, spray foam is the superior choice. The combination of higher R-value, integrated air sealing, moisture resistance, and lifetime durability makes it the most cost-effective long-term investment. Add in available Ontario rebates through the Home Renovation Savings Program (up to $7,700) and the Canada Greener Homes Loan ($40,000 at 0% interest), and spray foam becomes accessible to almost every budget.
That said, fiberglass still makes sense in specific situations, particularly for budget-conscious attic top-ups where moisture is not a concern. We are happy to assess your home and recommend the right solution for each area.