Heat pump sizing calculator
Find the right heat pump size for your home. Enter your floor area and climate to get an estimated capacity in BTU and tons — a solid starting point before a professional load calculation.
How it works
- Takes your conditioned floor area and climate zone.
- Applies typical BTU-per-square-foot factors for heating and cooling.
- Returns an estimated size in BTU and tons.
What changes your result
- Floor area and ceiling height
- Your climate zone and design temperature
- Insulation, window and air-sealing quality
- Whether the unit must cover heating, cooling, or both
Frequently asked questions
What size heat pump do I need?
As a rough guide, homes need about 20–30 BTU per square foot depending on climate and insulation — roughly 1 ton per 600–800 sq ft. This calculator estimates it from area and climate; a Manual J load calc confirms it.
Is it bad to oversize a heat pump?
Yes. An oversized unit short-cycles, leaving humidity high and comfort uneven while wearing out faster. Right-sizing — or a modulating inverter unit — keeps efficiency high. Don’t simply match an old furnace’s size.
Can one heat pump heat and cool a whole house?
Often yes. A correctly sized central or multi-zone heat pump handles both year-round. Large or poorly insulated homes may need multiple zones; cold climates benefit from cold-climate-rated models.