Quick answer
Cellulose and fiberglass are both blown‑in insulation options for attics. Cellulose is made from recycled paper treated with fire retardant, offers slightly higher R‑value per inch and better air‑sealing, while fiberglass is a glass‑fiber product that is inexpensive and widely available. Both meet Ontario’s energy‑efficiency goals, and Spray Foam Kings can install either material, remove existing insulation, and help you apply for provincial rebates.
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Understanding cellulose insulation
Cellulose insulation is produced from post‑consumer newspaper and other recycled paper fibres that are blended with a fire‑retardant solution (often borates). It is installed with a blowing machine that distributes the loose fibres uniformly across the attic floor or cavity. Because the fibres are dense and interlock, cellulose fills gaps around joists, wiring and other obstructions, providing a modest air‑sealing benefit.
Key points:
- R‑value: Approximately 3.5 – 3.8 per inch, a little higher than standard fiberglass batts.
- Moisture handling: The paper fibres can absorb a small amount of moisture without losing insulating ability, but prolonged dampness can lead to settling.
- Environmental impact: Uses up to 85 % recycled content, making it one of the greener insulation choices.
- Fire safety: Treated with fire‑retardant chemicals to meet Canadian fire‑code requirements.
Understanding fiberglass insulation
Fiberglass insulation consists of fine glass fibres that are spun into a loose‑fill product. Like cellulose, it is blown into the attic using specialised equipment. Fiberglass is non‑combustible and does not support mould growth, but the loose fibres do not seal air leaks as effectively as cellulose.
Key points:
- R‑value: About 2.9 – 3.4 per inch, slightly lower than cellulose.
- Moisture handling: Does not absorb water; however, if moisture accumulates, it can lose effectiveness and promote mould on surrounding surfaces.
- Environmental impact: Made from sand and recycled glass, but the manufacturing process is energy‑intensive.
- Fire safety: Naturally fire‑resistant; no additional chemicals required.
Direct comparison
| Characteristic | Cellulose | Fiberglass |
|---|---|---|
| Primary material | Recycled paper fibres + fire retardant | Glass fibres (sand & recycled glass) |
| Typical R‑value per inch | 3.5 – 3.8 | 2.9 – 3.4 |
| Air‑sealing ability | Moderate (fills gaps well) | Low (fibres remain loose) |
| Moisture tolerance | Can absorb limited moisture safely | Does not absorb; moisture reduces performance |
| Installation method | Blown‑in with a machine | Blown‑in with a machine |
| Typical cost (Toronto) | Included in your free written quote | Included in your free written quote |
| Environmental rating | High recycled content | Moderate recycled content |
| Rebate eligibility (Ontario) | Eligible under Canada Greener Homes and Enbridge HER+ programs (handled by Spray Foam Kings) | Same eligibility as cellulose (handled by Spray Foam Kings) |
Cost considerations
| Factor | Why it matters | Price (if listed) |
|---|---|---|
| Material cost | Determines overall project expense | — |
| Installation labor | Skilled crew ensures proper density and coverage | — |
| Removal of old insulation | Necessary to avoid mixing old and new material; impacts labour time | $400 – $800 CAD for 1,200 sq ft (depth & access dependent) |
| Rebate potential | Can offset a large portion of material & labour costs | Up to $10,600 CAD through Enbridge HER+ and Canada Greener Homes (Spray Foam Kings manages paperwork) |
| Warranty coverage | Protects against delamination, shrinkage, adhesion failures | Workmanship warranty – repairs at no charge |
| Lifespan of material | Affects long‑term value and need for future upgrades | 25 – 30+ years under normal conditions |
Key factors to consider when choosing between cellulose and fiberglass
FACTORS: Air‑sealing – Cellulose fills gaps better, reducing drafts; Fiberglass leaves more voids. R‑value target – Cellulose reaches higher R‑value per inch, useful for limited attic depth. Moisture environment – If the attic is prone to occasional dampness, cellulose’s moisture tolerance can be advantageous. Budget – Fiberglass generally has a lower material cost, but labour and removal fees are comparable. Environmental preference – Cellulose’s high recycled content makes it the greener option for many homeowners.
Frequently asked questions
How much attic insulation cost in Toronto?
The total cost depends on the material, attic size and any removal work. For a typical 1,200 sq ft attic, Spray Foam Kings charges $400 – $800 to remove existing insulation. The cost of installing new blown‑in insulation (cellulose or fiberglass) is not listed in our pricing sheet, but the company provides a free, written, itemised quote before any work begins.
Who makes cellulose insulation?
Cellulose insulation is produced by several manufacturers that process recycled newspaper and other paper waste into loose‑fill fibres, then treat them with fire‑retardant chemicals. In Ontario, the product is supplied to contractors like Spray Foam Kings for residential installations.
How do I apply for an attic insulation rebate in Ontario?
Spray Foam Kings is a registered Enbridge HER+ partner and also qualifies for the Canada Greener Homes program. The company handles all rebate paperwork on your behalf. After installation, you can receive up to $10,600 in combined rebates, depending on eligibility.
What is the recommended R‑value for attic insulation in Ontario?
Ontario’s building guidelines suggest a minimum R‑value of R‑20 for most residential attics. Achieving this level with cellulose typically requires about 5.5 inches of material, while fiberglass needs roughly 6 inches. Spray Foam Kings can calculate the exact depth needed for your attic’s dimensions.
Does the Ontario government offer a rebate for attic insulation?
Yes. Homeowners can receive rebates through the Enbridge Home Energy Rebate (HER+) program and the Canada Greener Homes program. Spray Foam Kings assists with the application process and ensures all documentation meets provincial requirements.
Is spray foam insulation better than fiberglass?
Spray foam (open‑cell or closed‑cell) provides higher R‑values per inch (R‑3.7 and R‑6 respectively) and creates an air‑tight barrier, which fiberglass cannot match. However, for many attic retrofits, blown‑in cellulose or fiberglass remains a cost‑effective choice, especially when combined with proper air sealing. Spray Foam Kings offers both spray foam and blown‑in options, allowing you to select the solution that fits your performance goals and budget.
For more details on our attic services, see:
- Attic Spray Foam Insulation Services
- Blown‑In Insulation Toronto – Cellulose & Fiberglass
- Attic Insulation Removal Toronto
- Spray Foam vs Fiberglass in Toronto
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Last updated November 6, 2026.