Heat PumpBuying Guide2025-09-08
How to Size a Heat Pump Correctly
Right-sizing a heat pump to your load — not the old furnace — is critical for comfort and efficiency.
Heat pump sizing is even more important than furnace sizing because oversizing hurts both comfort and efficiency.
Why sizing is critical
An oversized heat pump short-cycles, struggles to dehumidify in summer, and wastes the efficiency advantage. Undersizing leans too hard on backup heat in winter.
How it's done
A Manual J load calculation plus the unit's low-temperature capacity data determine the right size for your home and climate zone.
Key takeaways
- Size to a load calculation, not the old unit
- Check low-temperature capacity, not just nominal tons
- Avoid oversizing — it hurts efficiency and comfort
- Account for insulation and air-sealing
Need help with your heat pump?
Licensed, gas-certified technicians serving Greater Vancouver since 1999. CombiBoiler.ca — A division of ROMA Heating Ltd..
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