Data last verified: August 2026
Heat Pump Sizing Calculator
Direct answer
Estimate your heat pump size from four inputs: home square footage, climate zone (1–8), insulation level, and window area. We use a transparent rule-of-thumb — roughly 500 sq ft/ton in the coldest zones up to ~1,200 sq ft/ton in the hottest — adjusted for insulation and glazing. This is a screening estimate, not a full ACCA Manual J load calculation.
How the estimate works
Climate zones follow the U.S. energy-code bands (1 = hottest, 8 = coldest). Colder zones have larger heating loads, so they need more capacity per square foot (smaller sq ft/ton). Poor insulation and a high window-to-floor ratio raise the load and the recommended size. A real install should confirm with a full Manual J and size the heating side for your coldest design day, not the annual average.
Disclaimer: Estimate only, for planning. Efficiency, duct losses, and local climate micro-variation are not modeled. Hire a licensed contractor for a proper Manual J before purchasing. Not HVAC advice.
Data sources & methodology
- ACCA Manual JResidential load calculation standard.
- ENERGY STARSizing and cold-climate heat-pump guidance.
Methodology and citations are maintained by the PVFig editorial team. Where an official schedule is not yet loaded, results are shown as model estimates and the source is stated as a reference.