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Attic insulation savings
Last reviewed November 2, 2026
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Your details
Roughly the footprint of your top floor.
~3.2 per inch of fibreglass batt; ~3.5 for blown cellulose.
R-50 to R-60 recommended.
Blown-in top-up: ~$1.50–$3.50.
HRS attic route: up to $1,250.
Your estimate
Heating energy saved
2,503 kWh
≈ 255 m³ of gas
Annual savings
$124
heating plus a small cooling benefit
Payback
8.1 yrs
Net cost $1,000 after rebate
Heat loss through attic, before
0.41 W/m²·K
Heat loss through attic, after
0.10 W/m²·K
76% less
Air sealing the attic floor first (pot lights, top plates, plumbing stacks, the hatch) often saves as much as the insulation itself and prevents moisture problems. Read our attic insulation guide and air sealing guide.
Assumptions and method
Conductive heat loss = U × area × heating degree days × 24 h. Effective R-value is reduced 10% for framing and installation gaps, plus about R-3 for the drywall ceiling and air films.
Regional heating degree days: 3,600. Heat cost per kWh: gas at $0.45/m³ and 95% efficiency; electricity at $0.16/kWh; heat pump at regional seasonal COP 2.8.
Air-leakage savings from air sealing are not included and can be substantial. Diminishing returns are real: going from R-12 to R-50 saves far more than R-40 to R-60.