Ontario · climate zone 7A · prices and rebates checked October 8, 2026
Insulation and upgrade payback calculator for Thunder Bay
Thunder Bay has 5,405 heating degree-days a year (climate zone 7A), and NRCan recommends about R-80 in an attic here. For a typical detached house of about 1,600 sq ft (149 m²) built between 1966 and 1980 with a gas furnace, mid-efficiency, topping up the attic from R-20 to R-60 saves about $52 a year at $0.314/m³ and costs about $1,200–$1,960; the smallest open rebate that applies (Home Renovation Savings (no assessment)) is $600–$800. In an electrically heated house the same attic saves about $195 a year.
Heating degree-days
5,405
NBC climate zone 7A
NRCan attic target
R-80
code minimum for new homes R-59.2
Natural gas, one more m³
$0.314/m³
used for every saving
Open rebate programs
2
Home Renovation Savings (with assessment); Home Renovation Savings (no assessment)
Upgrade payback calculator for Thunder Bay
Pre-filled for a typical 1966–1980 house in Thunder Bay with Thunder Bay'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.
Thunder Bay at a glance: standard upgrades for a 1966–1980 house
Detached, about 1,600 sq ft over a full basement, two storeys, with the era's typical insulation (attic R-20, walls RSI 2.1, uninsulated basement walls, double-glazed windows). Savings use the price of one more unit of energy; costs are installed ranges where we could verify one.
| Upgrade | Saved a year | Cost and rebate | Payback | 20 years |
|---|---|---|---|---|
| Attic insulationR-20 → R-60 over 800 sq ft | $524.9 GJ · 4.3% | $1,200–$1,960rebate $600–$800 | 12–22 years | $1,030 |
| Wall insulationR-10 exterior insulation: RSI 2.1 → 3.9 over 1,580 sq ft | $11511.2 GJ · 9.7% | get a quoterebate $1,200 | enter a cost | $2,340 |
| Basement wall insulationRSI 0.7 → 3.5 over 890 sq ft of wall | $18517.7 GJ · 15.3% | get a quoterebate $900 | enter a cost | $3,700 |
| New windows15 windows: U 2.86 → 1.22 | $11010.3 GJ · 9.0% | $12,000–$18,000rebate $1,500 | 97 years to over 100 years | $2,160 |
| Air sealingA 20% cut in air leakage (NRCan: about 25% of heat loss) | $454.3 GJ · 3.8% | $350–$1,500rebate $200 | 3.3–29 years | $905 |
| Thermostat setback3.0 °C lower for 8 hours a day | $726.9 GJ · 6.0% | $0 | right away | $1,450 |
| Upgrade | Saved a year | Cost and rebate | Payback | 20 years |
|---|---|---|---|---|
| Attic insulationR-20 → R-60 over 800 sq ft | $1954.9 GJ · 4.3% | $1,200–$1,960rebate $600–$800 | 3.0–5.9 years | $3,940 |
| Wall insulationR-10 exterior insulation: RSI 2.1 → 3.9 over 1,580 sq ft | $44511.2 GJ · 9.7% | get a quoterebate $1,200 | enter a cost | $8,930 |
| Basement wall insulationRSI 0.7 → 3.5 over 890 sq ft of wall | $70517.7 GJ · 15.3% | get a quoterebate $900 | enter a cost | $14,120 |
| New windows15 windows: U 2.86 → 1.22 | $41510.3 GJ · 9.0% | $12,000–$18,000rebate $1,500 | 25–40 years | $8,270 |
| Air sealingA 20% cut in air leakage (NRCan: about 25% of heat loss) | $1754.3 GJ · 3.8% | $350–$1,500rebate $200 | under 1 to 7.5 years | $3,450 |
| Thermostat setback3.0 °C lower for 8 hours a day | $2756.9 GJ · 6.0% | $0 | right away | $5,520 |
The house needs about 115 GJ of heat a year here. Walls in this era already hold about RSI 2.1, so dense-packing gains nothing and the table shows R-10 of exterior insulation instead. Wall and basement prices start blank because we couldn't verify a 2025–2026 Canadian cost; the 20-year column shows what each upgrade is worth to compare with a quote.
Rebates for these upgrades in Ontario
Home Renovation Savings (Enbridge Gas + Save on Energy) is the only province-wide rebate. The assessment path covers insulation, windows, doors, air sealing, heat pump water heaters and the assessment itself, but its follow-up assessment must be done by December 31, 2026. The no-assessment path covers heat pumps, attic insulation (participating contractors only) and smart thermostats.
Attic insulation
Home Renovation Savings (with assessment) Open
Up to $1,500 (R-12 or less to at least R-50); $1,200 (above R-12 up to R-25, to at least R-50); $900 (above R-25 up to R-35, to at least R-50). Cathedral ceiling/flat roof $780.
Conditions: Initial EnerGuide assessment before any work, at least two recommended upgrades, then a follow-up assessment with the same service organization. Only the program's seven approved service organizations qualify: AmeriSpec of Canada, Canada Energy Audit, Energuy, Energy Werx, Greenbrain, NRGwise and The Home Inspectors Group. Homeowners only (an owner with tenants applies); detached, semi-detached, row/townhome or mobile home on a permanent foundation (stacked townhomes…
Deadline: Follow-up assessment must be scheduled by November 30, 2026 and completed within 180 days of the initial assessment or by December 31, 2026, whichever comes first (Terms and Conditions, version Nov 2025).
Program details · official page ↗ · checked October 8, 2026
Home Renovation Savings (no assessment) Open
Less than or equal to R-12 → R-50: $1,250; Greater than R-12 to R-25 → R-50: $1,000; Greater than R-25 to R-35 → R-50: $800 (maximum rebate). Cathedral ceiling or flat roof: $750 (≤R-25 to R-28) or $650 (≤R-12 to R-20).
Conditions: No assessment. Must use a participating contractor and "Contractor registrations for the attic program stream are currently closed", so check one serves your area. 100% of the roof assembly must be insulated. The help page says the rebate is 50% of the after-tax insulation cost up to the tier maximum and combined rebates from all sources can't exceed 50% of after-tax cost. Enbridge gas-heated homes, or Ontario-grid homes heated by electricity, propane, oil or wood (Cornwall…
Deadline: No end date on the current attic page. Our earlier 'installed by Nov 30, 2026 / submitted by Dec 31, 2026' could not be re-verified on today's official pages.
Program details · official page ↗ · checked October 8, 2026
Wall insulation
Home Renovation Savings (with assessment) Open
Exterior wall: $3,600 (greater than R-20 added); $2,100 (greater than R-12 to R-20); $1,200 (R-7.5 to R-12).
Conditions: Initial EnerGuide assessment before any work, at least two recommended upgrades, then a follow-up assessment with the same service organization. Only the program's seven approved service organizations qualify: AmeriSpec of Canada, Canada Energy Audit, Energuy, Energy Werx, Greenbrain, NRGwise and The Home Inspectors Group. Homeowners only (an owner with tenants applies); detached, semi-detached, row/townhome or mobile home on a permanent foundation (stacked townhomes…
Deadline: Follow-up assessment must be scheduled by November 30, 2026 and completed within 180 days of the initial assessment or by December 31, 2026, whichever comes first (Terms and Conditions, version Nov 2025).
Program details · official page ↗ · checked October 8, 2026
No wall rebate on the no-assessment path.
Basement wall insulation
Home Renovation Savings (with assessment) Open
Foundation insulation up to $2,300: basement wall $1,500 (above R-22) or $900 (R-10 to R-22); basement slab $500 (at least 50% of slab, minimum R-3.5); foundation header $300 (at least 80%, minimum R-20, only with wall insulation). Crawl space walls $1,200/$600; crawl space ceiling $1,200 (greater than R-24).
Conditions: Initial EnerGuide assessment before any work, at least two recommended upgrades, then a follow-up assessment with the same service organization. Only the program's seven approved service organizations qualify: AmeriSpec of Canada, Canada Energy Audit, Energuy, Energy Werx, Greenbrain, NRGwise and The Home Inspectors Group. Homeowners only (an owner with tenants applies); detached, semi-detached, row/townhome or mobile home on a permanent foundation (stacked townhomes…
Deadline: Follow-up assessment must be scheduled by November 30, 2026 and completed within 180 days of the initial assessment or by December 31, 2026, whichever comes first (Terms and Conditions, version Nov 2025).
Program details · official page ↗ · checked October 8, 2026
No basement rebate on the no-assessment path.
Air sealing
Home Renovation Savings (with assessment) Open
$200 (achieve the base target on your Renovation Upgrade Report); $250 (achieve 10% or more above the base target).
Conditions: Initial EnerGuide assessment before any work, at least two recommended upgrades, then a follow-up assessment with the same service organization. Only the program's seven approved service organizations qualify: AmeriSpec of Canada, Canada Energy Audit, Energuy, Energy Werx, Greenbrain, NRGwise and The Home Inspectors Group. Homeowners only (an owner with tenants applies); detached, semi-detached, row/townhome or mobile home on a permanent foundation (stacked townhomes…
Deadline: Follow-up assessment must be scheduled by November 30, 2026 and completed within 180 days of the initial assessment or by December 31, 2026, whichever comes first (Terms and Conditions, version Nov 2025).
Program details · official page ↗ · checked October 8, 2026
Only via the assessment path; no stand-alone air sealing rebate.
Windows and doors
Home Renovation Savings (with assessment) Open
$100 per rough opening for each window, door, skylight or sliding door replaced with an ENERGY STAR certified model.
Conditions: Initial EnerGuide assessment before any work, at least two recommended upgrades, then a follow-up assessment with the same service organization. Only the program's seven approved service organizations qualify: AmeriSpec of Canada, Canada Energy Audit, Energuy, Energy Werx, Greenbrain, NRGwise and The Home Inspectors Group. Homeowners only (an owner with tenants applies); detached, semi-detached, row/townhome or mobile home on a permanent foundation (stacked townhomes…
Deadline: Follow-up assessment must be scheduled by November 30, 2026 and completed within 180 days of the initial assessment or by December 31, 2026, whichever comes first (Terms and Conditions, version Nov 2025).
Program details · official page ↗ · checked October 8, 2026
Caps and bonuses
Up to $5,000 per home for natural gas homes; up to $10,000 for electric, oil, propane or wood homes — "inclusive of the $600" assessment rebate. Rebates "shall not exceed the total actual cost". source ↗
$500 Multi-Upgrade Bonus: "Participants with a post-renovation assessment date on or after January 5, 2026 who install three (3) or more qualified upgrades under the Assessment program will receive a $500 bonus rebate." Windows, doors, skylights and sliding doors together count as one upgrade. source ↗
Common questions in Thunder Bay
Does attic insulation pay for itself in Thunder Bay?
For a typical detached house of about 1,600 sq ft (149 m²) built between 1966 and 1980, going from R-20 to R-60 saves about $52 a year with a mid-efficiency gas furnace and $195 with electric baseboards, counted at the price of one more unit of energy. At HomeStars' $1.50–$2.45 per sq ft (about $1,200–$1,960) and a $600–$800 rebate, simple payback is 12–22 years (3.0–5.9 years for an electrically heated house). Attics with less than R-20 save more.
What insulation rebates are open in Thunder Bay?
As of October 8, 2026: Attic insulation: Home Renovation Savings (with assessment) (Up to $1,500 (R-12 or less to at least R-50); $1,200 (above R-12 up to R-25, to at least R-50); $900 (above R-25 up to R-35, to at least R-5); Home Renovation Savings (no assessment) (Less than or equal to R-12 → R-50: $1,250; Greater than R-12 to R-25 → R-50: $1,000; Greater than R-25 to R-35 → R-50: $800 (maximum rebate)) Wall insulation: Home Renovation Savings (with assessment) (Exterior wall: $3,600 (greater than R-20 added); $2,100 (greater than R-12 to R-20); $1,200 (R-7.5 to R-12).) Basement wall insulation: Home Renovation Savings (with assessment) (Foundation insulation up to $2,300: basement wall $1,500 (above R-22) or $900 (R-10 to R-22); basement slab $500 (at least 50% of slab, mini). Conditions apply (most need an EnerGuide evaluation before the work); the calculator counts the smallest amount for each and lets you switch it off.
How much insulation should an attic have in Thunder Bay?
NRCan's Keeping the Heat In recommends about R-80 (RSI 14.1) for an attic in climate zone 7A, which covers Thunder Bay at 5,405 degree-days. The National Building Code minimum for a new house here is R-59.2 without a heat recovery ventilator. Our calculator caps its default target at R-60.
Are new windows worth it for energy savings in Thunder Bay?
Rarely on energy alone. Replacing 15 double-glazed windows with ENERGY STAR models saves about $110 a year in a gas-heated house and $415 with electric heat, against $12,000–$18,000 at HomeStars' $800–$1,200 a window: payback 97 years to over 100 years. Replace windows when they fail or for comfort; air sealing and attic insulation pay back much faster.
How much do air sealing and a thermostat setback save in Thunder Bay?
Cutting air leakage by 20% saves about $45 a year in a typical gas-heated house here (NRCan: about a quarter of heat loss is air leakage), and turning the thermostat down 3 °C for 8 hours a night saves about $72 a year (NRCan: about 2% per degree over eight hours). Heat pumps should be set back no more than 2 °C.
How we calculate this
1. Heat saved by insulation and windows
heat saved (GJ/yr) = area × (1/RSI before − 1/RSI after) × 5,405 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 7A, 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.
More for Thunder Bay
Sources
- NRCan, HOT2000 Climate Map: heating degree-days and design temperatures for 403 locations ↗
- NRCan Comprehensive Energy Use Database 2023, Ontario residential Table 33 (heating requirement per floor area by vintage) ↗
- NRCan, Heating with Gas (revised October 2012): Table 2 energy content, Table 3 efficiencies, Table 4 heating loads ↗
- NRCan, Keeping the Heat In, Section 2: How your house works (Table 2-1 recommended insulation by zone) ↗
- NRCan, Keeping the Heat In, Section 3: Table 3-1 insulation values ↗
- NRCan, Keeping the Heat In, Section 5: Roofs and attics ↗
- NRCan, Keeping the Heat In, Section 6: Basements ("about 25 percent of a home's total heat loss") ↗
- NRCan, Keeping the Heat In, Section 7: Walls ("about 20 percent of heat loss") ↗
- NRCan, Keeping the Heat In, Section 8: Windows and doors ↗
- NRCan, Keeping the Heat In, Section 9: Thermostats ("2 percent per 1 °C over eight hours"; "about 25 percent of heat loss can be due to air leakage") ↗
- National Building Code of Canada 2020 (climate zones, Section 9.36 minimum insulation, smoke alarms 9.10.19) ↗
- NRCan consumer guide to windows (2003): conventional windows RSI 0.35 (R-2) ↗
- NRCan, ENERGY STAR Canada technical specification for windows (Version 5, U ≤ 1.22) ↗
- Wikipedia, Blower door (natural ACH ≈ ACH50 ÷ 20, after Persily and Kronvall as reported by Sherman, "The Use of Blower-Door Data", Indoor Air 1995) ↗
- Wikipedia, Air changes per hour (natural ACH is 10–25 times smaller than ACH50) ↗
- Wikipedia, Table of specific heat capacities (air at room conditions: 0.00121 J/cm³·K = 1.21 kJ/m³·K) ↗
- NRCan, Heating and cooling with a heat pump (modified 2025-12-24) ↗
- NRCan, ENERGY STAR water heaters (space heating 63.6%, water heating 17.2% of home energy) ↗
- Hydro-Québec, Electricity consumption by use (electrically heated household: 54% heating and air conditioning) ↗
- HomeStars, Attic insulation cost (updated 21/08/2026) ↗
- HomeStars, Window replacement cost (updated 21/08/2026) ↗
- Dunsky Energy + Climate for the Canadian Climate Institute, Heat Pumps Pay Off: technical report (2024) ↗
- Home Renovation Savings (with assessment) (checked 2026-10-08) ↗
- Home Renovation Savings (no assessment) (checked 2026-10-08) ↗
- Home Renovation Savings (with assessment) (checked 2026-10-08) ↗
- Electricity price: Toronto Hydro ↗
- Natural gas price: Enbridge Gas Inc. - Enbridge Gas Distribution ↗
- Heating oil price: Statistics Canada table 18-10-0001-01 ↗
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