System sizing

Heat Pump Size Calculator

Build a planning target for heat-pump capacity using area, climate, and envelope quality.

Your planning inputsUpdates automatically

Conditioned floor area

sq ft

Area served by this heat pump.

Primary design climate

Choose the condition that most often drives capacity.

Envelope quality

A tight, insulated house needs less peak capacity.

Estimated result

4 nominal tons

50k BTU/h planning load. Verify both sensible and latent performance at design conditions.

How to use this estimate

In a cold climate, verify delivered capacity at the local winter design temperature—not only the nominal rating.
Ask how the contractor selected auxiliary heat and the balance point.
Variable-speed systems still need an accurate load range.

Transparent method

We expose the planning formula so you can challenge it and replace assumptions with local evidence.

floor area × climate load factor × envelope factor, converted at 12,000 BTU/h per ton

What this calculator cannot see

Nominal tonnage does not show low-temperature performance.
Use certified manufacturer performance data and a Manual J/S selection before purchase.

Professional verification

Use this result to prepare questions and compare scenarios. Final equipment selection, electrical work, refrigerant work, combustion, duct design, and permitting should be handled by qualified professionals following local codes and manufacturer instructions.