Quick answer: Attic insulation is usually the simplest upgrade for a warmer, quieter home. Pro Home Insulation seals the air leaks first, then tops up your attic with blown-in cellulose or fiberglass to R-50 or R-60, with baffles for airflow and an insulated, weatherstripped hatch. Through Ontario’s Home Renovation Savings Program, the standalone attic rebate pays back 50% of the after-tax insulation cost, up to $1,250, with no energy assessment needed. Amounts can change, and the program is currently scheduled to run until March 31, 2027.
Updated November 2026
On this page
- 7 signs your attic needs more insulation
- How to check your attic insulation yourself
- Attic rebate tiers: what you can get back
- Attic insulation by the numbers
- Blown-in cellulose vs fiberglass vs spray foam for attics
- Our attic insulation process, step by step
- Attic insulation checklist
- example project
- Framework: 6 questions to ask any attic insulation contractor
- Frequently asked questions
- Get a free attic assessment
Most homes in Toronto and the GTA have less attic insulation than today’s building code targets. New homes in most of Ontario are built to about R-60 in the attic. Many older homes have R-12 to R-25, or less where the insulation has settled or been disturbed.
The good news is that an attic top-up is a short job with a clear result, and right now it can come with a meaningful rebate. See our rebates hub for every current program.
7 signs your attic needs more insulation
- You can see the tops of the ceiling joists. If the insulation does not cover the joists, you likely have less than R-25.
- Upstairs rooms are hot in summer and cold in winter. A thin attic layer lets heat move freely through the ceiling.
- Ice dams or long icicles form on the eaves. Warm air leaking into the attic melts snow on the roof, which refreezes at the edge.
- Snow melts off your roof faster than your neighbours’. That is heat escaping through the ceiling.
- The insulation looks flat, patchy or dark. Old insulation settles, and dark streaks often mark air leaks.
- Your home was built before the 1990s and never upgraded. Insulation levels were much lower in older codes.
- Drafts and dust. Air that leaks through the ceiling carries dust and moisture with it.
How to check your attic insulation yourself
You can get a rough idea in about five minutes.
- Go up safely. Use a sturdy ladder, wear a mask, gloves and long sleeves, and step only on the joists.
- Measure the depth. Push a ruler down to the drywall in a few spots and note the average.
- Do the math. Multiply inches by about R-3.5 for cellulose or about R-2.5 to R-3 for fiberglass. Ten inches of cellulose is roughly R-35.
- Look for warning signs. Note any wet spots, mould, droppings, or grey-brown pebbles that could be vermiculite. If you see vermiculite, do not touch it.
Our step-by-step guide on how to check your attic insulation R-value has photos of what to look for.
Attic rebate tiers: what you can get back
Here is the standalone attic path of the Home Renovation Savings Program. You do not need an energy assessment for this path. The rebate is 50% of the after-tax insulation cost, up to the maximum for your tier.
| Your attic before the upgrade | Upgrade to at least | Maximum rebate |
|---|---|---|
| R-12 or less | R-50 | up to $1,250 |
| Above R-12 to R-25 | R-50 | up to $1,000 |
| Above R-25 to R-35 | R-50 | up to $800 |
| Cathedral or flat roof, R-25 or less | R-28 | up to $750 |
| Cathedral or flat roof, R-12 or less | R-20 | up to $650 |
If you are planning two or more upgrades, the bundle path may pay more for the attic: up to $1,500 for R-12 or less, or up to $1,200 for above R-12 to R-25, plus $600 back on your energy assessment. You cannot claim an attic rebate from both paths. Compare them on our attic insulation rebate Ontario page.
How much heat flow does a top-up cut? Using simplified physics, heat flow through the insulation layer is proportional to 1/R:
| Upgrade | Heat flow through the insulation layer (simplified) |
|---|---|
| R-12 to R-50 | about 76% less (1 − 12 ÷ 50) |
| R-20 to R-60 | about 67% less (1 − 20 ÷ 60) |
| R-25 to R-50 | about 50% less (1 − 25 ÷ 50) |
This is heat flow through the insulation only, not a prediction of your energy bill.
Attic insulation by the numbers
- About R-60 is the Ontario Building Code (SB-12) target for attic ceilings in new homes in most of Ontario (Ontario Building Code).
- Air leakage accounts for about 20–30% of the heat lost from an older home (Natural Resources Canada).
- One small air leak can let in 100 times more moisture than diffusion through the same area (Natural Resources Canada).
- Nearly 1.2 million residential properties in Ontario were built in 1960 or earlier (Statistics Canada).
- More than 10% of Canada’s yearly energy use goes to heating homes (Natural Resources Canada).
Blown-in cellulose vs fiberglass vs spray foam for attics
| Blown-in cellulose | Blown-in fiberglass | Spray foam | |
|---|---|---|---|
| R-value per inch (about) | R-3.5 | R-2.5 to R-3 | R-3.5 to R-7 (open vs closed cell) |
| Depth for R-50 (about) | 14–15 inches | 17–20 inches | Rarely used to reach R-50 in open attics |
| Strengths | Dense, fills gaps around wires and nails | Light, does not absorb water | Air seals and insulates in one step |
| Best fit | Most open attics | Open attics, especially low-slope areas | Cathedral ceilings, flat roofs, tight spaces |
| Qualifies for attic rebate | Yes, if target R-value is reached | Yes, if target R-value is reached | Yes, if target R-value is reached |
For an open attic, blown-in insulation is usually the most cost-effective way to reach R-50 or R-60. Spray foam makes more sense where there is no room for deep loose fill. Read the full cellulose vs fiberglass vs spray foam comparison, or see our spray foam insulation service.
Our attic insulation process, step by step
- Free assessment. We measure your current depth, check ventilation, and look for moisture, mould, pests or vermiculite. You get a written quote with the target R-value and rebate tier.
- Protect your home. We lay down floor coverings and run the hose through the hatch or a window, so the mess stays outside the living space.
- Air seal first. We seal top plates, pot light housings, plumbing and wiring holes, and the chimney chase with fire-rated materials. Learn more on our attic air sealing page.
- Install baffles. Baffles at the eaves keep the soffit vents open so outside air can flow under the roof deck.
- Prep the attic. We dam around the hatch, keep insulation away from chimneys and flues as required, and mark depth rulers across the attic.
- Blow in the insulation. We fill to an even depth that reaches R-50 or R-60, checking the rulers as we go.
- Insulate and weatherstrip the hatch. A hatch with no insulation is a big hole in an otherwise well-insulated ceiling.
- Document for your rebate. We take before-and-after photos and measurements and give you the paperwork you need for your application.
If your old insulation is wet, mouldy or full of droppings, it needs to come out first. See attic insulation removal.
Attic insulation checklist
- Measure your current insulation depth in three or more spots
- Check for vermiculite, mould, water stains or droppings
- Confirm bathroom and kitchen fans vent outside, not into the attic
- Ask for air sealing to be included in the quote
- Confirm baffles will be installed at the eaves
- Get the target R-value in writing (at least R-50 for the rebate)
- Confirm the hatch will be insulated and weatherstripped
- Choose your rebate path before work starts
- Keep your invoice, photos and depth readings for your application
example project
example — not a specific customer.
A 1970s two-storey home in Mississauga has about 6 inches of settled fiberglass, roughly R-15 to R-18. That places it in the “above R-12 to R-25” tier on the standalone attic path, with a maximum rebate of up to $1,000.
- Work: air sealing, baffles, hatch upgrade, and blown-in cellulose topped up to R-60.
- Assumed after-tax insulation cost (for illustration, not a quote): $2,400.
- 50% of the after-tax cost: $2,400 × 0.5 = $1,200.
- Rebate: the lower of $1,200 and the tier maximum, so up to $1,000.
- Net cost after rebate: $2,400 − $1,000 = $1,400.
If the same attic had R-12 or less, the tier maximum would be up to $1,250, and the full $1,200 (50% of cost) would be covered.
Framework: 6 questions to ask any attic insulation contractor
Use these when you compare quotes.
| Question | A good answer sounds like |
|---|---|
| What R-value will my attic reach? | A specific number, at least R-50, written on the quote |
| Is air sealing included? | Yes, with the areas listed (top plates, pot lights, penetrations, hatch) |
| Will you install baffles? | Yes, at every rafter bay with a soffit vent |
| How will you handle the hatch? | Insulated and weatherstripped, with a dam to hold loose fill |
| Are you a participating contractor for the rebate? | A clear yes, plus help with the paperwork |
| What if you find mould, pests or vermiculite? | Work stops, they explain options, and nothing is disturbed without a plan |
Frequently asked questions
How much attic insulation do I need in Ontario?
The Ontario Building Code targets about R-60 for attics in new homes in most of the province. To qualify for the standalone attic rebate, you need to reach at least R-50. With blown cellulose, R-60 works out to about 17 inches of depth.
Do I need to remove my old insulation first?
Usually not. If your old insulation is dry and clean, we blow new insulation right on top. Removal is only needed if it is wet, mouldy, contaminated by animals, or might be vermiculite.
How long does attic insulation take?
Most attic top-ups, including air sealing and baffles, take about one day. Larger attics or jobs that start with removal can take longer.
Is cellulose or fiberglass better for my attic?
Both work well when installed to the right depth. Cellulose is denser and packs in around wires and framing, while fiberglass is lighter and does not absorb water. We recommend one based on your attic’s framing, ventilation and access.
How do I claim the attic insulation rebate?
On the standalone attic path, a participating contractor completes the work and you submit the application with your invoice and documentation. Rebate cheques typically arrive within a few months of approval. Our guide on how to claim the attic insulation rebate walks through each step.
Can I get the rebate if I heat with electricity or oil?
Yes, the Home Renovation Savings Program is open to homeowners who heat with Enbridge natural gas, or with electricity, oil, propane or wood. You must own the home. Rebate amounts can change, so check current rebates before you book.
Will more insulation cause moisture problems?
Not when the attic is air sealed and ventilated properly. Most attic moisture comes from warm, damp household air leaking up through the ceiling, which is why we seal those leaks before adding insulation.
Do you serve my area?
We work across Toronto, the GTA and nearby Southern Ontario, including Toronto, Mississauga, Vaughan and Oakville. That covers Halton, Peel, York, Durham and Hamilton. If you are not sure whether we reach your street, call and ask.
Get a free attic assessment
With more than 10 years of experience in GTA attics, Pro Home Insulation will measure what you have, explain your rebate tier, and give you a clear written quote. Call (647) 250-0606 or Book online.