Key Takeaways
- An undersized heat pump runs continuously without maintaining setpoints during winter cold snaps.
- Over-sizing leads to rapid short-cycling, accelerating compressor wear and reducing summer dehumidification.
- Square footage alone cannot size a heat pump correctly; a recognized load calculation such as CSA F280 is required.
Why square footage alone is not enough
Two homes with the same floor area can have very different loads because of insulation, air leakage, windows, configuration, and location. Read our installation price guide.
Natural Resources Canada recommends that a professional determine heating and cooling loads using a recognized method such as CSA F280. See the LogisVert eligibility guide.
Key variables impacting heat load calculations
Square footage is only part of the equation: construction vintage, ceiling heights, window surface area, and solar exposure alter thermal demand. Check the best heat pumps guide.
The calculation must also consider the outdoor design temperature and the equipment’s actual capacity as outdoor temperature falls. Use our LogisVert rebate calculator.
Why heating capacity at -8 °C determines LogisVert grant amounts
Hydro-Québec LogisVert calculates subsidies strictly from certified heating capacity at -8 °C, rather than rated summer cooling capacity. Request a free match.
Review the manufacturer AHRI certificate with your contractor to verify your exact grant tier. Read our installation price guide.