70 Canadian cities · prices and programs checked October 8, 2026

Insulation and upgrade payback calculator

See what attic, wall and basement insulation, new windows, air sealing and a thermostat setback would save in your climate, what they cost, which rebates are open today and how long each takes to pay back. The savings are deliberately conservative.

Upgrade payback calculator for Toronto

Set up for Toronto, Ontario, as an example. Pick your city above to load its own climate, prices and open rebates.

Pre-filled for a typical 1966–1980 house in Toronto with Toronto's climate, prices and open rebates. The insulation levels are typical assumptions for the era, not measurements: change anything you know about your house. Nothing you enter leaves your browser.

Attic insulation Include in the total

Insulation nowR-

Insulate toR-

NRCan recommends R-55 for climate zone 5; we cap the default at R-60. The building code minimum for a new house here is R-49.2.

Attic areasq ft

Your quote$

Or cost per sq ft (low – high)

$ – $

HomeStars (updated 21/08/2026): "installation costs range from $1.50 to $2.45 per square foot"; Canadian attic jobs average $1,500–$3,000 including materials and installation.

Rebate to count

$32/yr · 3.1 GJ (4.1% of heating) · cost $1,200–$1,960 · $600–$800 rebate · payback 19–36 years

Wall insulation Include in the total

How

Dense-pack the cavities Add R-10 outside

Walls nowRSI

R-12

Wall areasq ft

Your quote$

We couldn't verify a 2025–2026 Canadian price for wall insulation, so this starts blank. NRCan: on an exterior retrofit the insulation is only about 15–20% of the cost.

Rebate to count

$77/yr · 7.4 GJ (9.7% of heating) · cost enter your quote · $1,200 rebate · payback enter a cost

Basement wall insulation Include in the total

Walls nowRSI

R-4

Insulate toRSI

R-20

Basement wall areasq ft

Your quote$

Rebate to count

$120/yr · 11.6 GJ (15.3% of heating) · cost enter your quote · $900 rebate · payback enter a cost

New windows Include in the total

Windows now

New windows

How manywindows

Your quote$

Or cost per window (low – high)

$ – $

HomeStars (updated 21/08/2026): $800–$1,000 for a double-hung and $900–$1,200 for a casement window, installed; bay and bow windows $2,500–$4,000.

Rebate to count

$71/yr · 6.8 GJ (9.0% of heating) · cost $12,000–$18,000 · $1,500 rebate · payback over 100 years to no payback

Air sealing Include in the total

Cut in air leakage%

Blower-door resultACH50

Leave the cut blank for our default: 20%, or 15% if your house tests under 4 ACH50. The blower-door number is on your EnerGuide report.

Cost (low – high)

$ – $

HomeStars (updated 21/08/2026): air sealing and ventilation "could add $350 to $1,500" to an attic insulation job.

Rebate to count

$30/yr · 2.8 GJ (3.8% of heating) · cost $350–$1,500 · $200 rebate · payback 5.0–44 years

Thermostat setback Include in the total

Turn it down by°C

Forhours a day

Thermostat cost$

NRCan suggests 17 °C when you're asleep or away and 20 °C when you're home, and not going below 17 °C. $0 if you already have a programmable thermostat; we couldn't verify a 2025–2026 price for a new one.

Rebate to count

$48/yr · 4.5 GJ (6.0% of heating) · cost $0 · no rebate counted · payback right away

Each upgrade on its own
Upgrade	Saved a year	Cost and rebate	Payback	20 years
Attic insulationR-20 → R-55 over 800 sq ft	$32105 m³ a year	$1,200–$1,960rebate $600–$800	19–36 years	$650
Wall insulationR-10 exterior insulation: RSI 2.1 → 3.9 over 1,580 sq ft	$77245 m³ a year	your quoterebate $1,200	enter a cost	$1,540
Basement wall insulationRSI 0.7 → 3.5 over 890 sq ft of wall	$120385 m³ a year	your quoterebate $900	enter a cost	$2,430
New windows15 windows: U 2.86 → 1.22	$71225 m³ a year	$12,000–$18,000rebate $1,500	over 100 years to no payback	$1,430
Air sealingA 20% cut in air leakage (NRCan: about 25% of heat loss)	$3095 m³ a year	$350–$1,500rebate $200	5.0–44 years	$595
Thermostat setback3.0 °C lower for 8 hours a day	$48150 m³ a year	$0	right away	$950

Savings use the price of one more unit of energy, not your average price. Each upgrade is shown on its own against your house as it is now; the total above accounts for overlap. Payback = (cost − rebate) ÷ yearly saving; the 20-year figure has no price increases or discounting.

How we calculate this

1. Heat saved by insulation and windows

heat saved (GJ/yr) = area × (1/RSI before − 1/RSI after) × 3,559 degree-days × 86,400 s ÷ 10⁹ × F

F is a conservative factor: 0.75 above grade (the sun, people and appliances supply some heat, and no installation is perfect) and 0.4 for basement walls (most of the wall is below grade, where the ground stays far warmer than winter air). Windows use U-values instead of 1/RSI.

2. Typical starting points

Attic: R-12 before 1966, R-20 (1966–80), R-28 (1981–95), R-40 (1996–2010), R-50 (2011+). Target: NRCan's retrofit recommendation for climate zone 5, capped at R-60.
Walls: RSI 0.7 (empty, before 1946), 1.4 (1946–65), 2.1 (1966–95), 3.0 (1996–2010), 3.4 (2011+). Dense-packing a 2×4 cavity gives about RSI 2.1 (cellulose is RSI 0.63 per 25.4 mm, NRCan Table 3-1); R-10 of exterior insulation adds RSI 1.76.
Basement walls: RSI 0.7 before 1981 (bare concrete plus the soil against it), 2.1 for 1981–2010, 3.5 since; target RSI 3.5 (R-20).
Windows: 12% of floor area (1.2 m² each), single with storm before 1966, double clear 1966–95, double low-e after.

These starting values are AuditYourHome planning assumptions for a typical house of each era, not survey results: we could not verify a Canadian table of insulation levels by year built. Change them to match your house; an EnerGuide evaluation measures them.

3. Air sealing

Without a blower-door number we use NRCan's statement that typically about 25% of heat loss is air leakage: saving = 25% × reduction × heating need × 0.75. With your EnerGuide result (ACH50), everyday leakage is ACH50 ÷ 20, near the conservative end of the 10–25 range used in the field, and:

heat saved = drop in natural air changes × house volume × 1.21 kJ/m³·°C × degree-days × 24 ÷ 10⁶ × 0.75

We assume a 20% reduction (15% if the house is already under 4 ACH50); rebate programs pay for measured cuts of 10%, 20% and 30%.

4. Thermostat setbacks

NRCan: “A drop of 1°C (2°F) over an eight-hour period can save about 2 percent on your heating energy consumption.” Saving = 2% × degrees × hours ÷ 8. Heat pumps are limited to a 2 °C setback, NRCan's advice, because deep setbacks can bring on backup heat.

5. Caps, overlap and your bills

No single measure may save more than 35% of the heating need, and all of them together no more than 60%. Measures overlap (a better attic leaves less heat for new windows to save), so the combined saving is 1 − (1 − a)(1 − b)…, always less than the simple sum. If you enter bills, every saving is scaled by how your use compares with a typical house (between 0.5× and 1.6×).

6. Dollars, rebates and payback

payback (years) = (installed cost − rebate) ÷ yearly saving at the price of one more unit of energy

Rebates use each program's lowest published amount per unit (per home, per window, per sq ft or per sq ft × R-value added), only for programs open today and only where your heating fuel qualifies; you can switch each one off. The 20-year saving is the yearly saving × 20, with no price inflation or discounting. Where we could not verify a 2025–2026 installed cost (walls, basements, exterior insulation), the cost starts blank: enter your quote.