What size heat pump do I need?
Enter your total conditioned floor area, your climate and how well your home is insulated — you'll get the estimated cooling and heating loads and the recommended heat pump size in kW and tons, instantly.
Your climate
UK, New Zealand, Pacific Northwest, Maritime Canada
Insulation quality
The heating load dominates at 11.0 kW. A 12.3 kW heat pump covers both seasons — size at or just above the calculated load.
Rule-of-thumb estimate — confirm with a professional Manual J load calculation before purchasing.
Load = floor area × climate factor × insulation multiplier. Recommended size = larger of cooling and heating loads, rounded up to nearest standard capacity (1.5 · 2 · 2.5 · 3 · 3.5 · 4 · 5 · 6 tons). No code values, no prices.
Common questions
- What size heat pump do I need for a 2,000 sq ft house?
- The answer depends heavily on climate. For a 2,000 sq ft (186 m²) home with average insulation, this calculator estimates: about 30,000 BTU/hr (2.5 tons / 8.8 kW) of cooling in a moderate climate and 50,000 BTU/hr (4.2 tons / 14.7 kW) of heating — so a 5-ton (17.6 kW) unit sized to the larger heating load. In a milder climate the heating load drops and a 3–3.5-ton unit may suffice. Select your specific climate and insulation above for a tailored estimate.
- How many tons of heat pump do I need per square foot?
- A common rule of thumb is 1 ton per 400–600 sq ft in a moderate climate with average insulation. Hot climates with poor insulation can need 1 ton per 350 sq ft or less; mild climates with good insulation can reach 1 ton per 700 sq ft. Because a heat pump must handle both heating and cooling, always size to the larger of the two loads — which in cold climates is usually the heating load.
- Is it better to oversize or undersize a heat pump?
- An oversized heat pump short-cycles — it reaches the set temperature quickly then shuts off before properly dehumidifying the air, leaving the room cool and clammy. Compressor wear also increases with frequent stop/start. A heat pump sized at or just above the calculated load is more efficient and more comfortable. ACCA recommends against oversizing by more than 15–25%.
- Can a heat pump replace both my furnace and air conditioner?
- Yes — a heat pump moves heat rather than generating it, providing cooling in summer and heating in winter from a single unit. Modern cold-climate heat pumps rated to −15°C (5°F) or lower can handle severe winters without a backup. In very cold climates a dual-fuel system — a heat pump for mild weather plus a gas furnace for the coldest days — delivers both efficiency and capacity.
- What is the most accurate way to size a heat pump?
- The accurate method is a Manual J residential load calculation (ACCA Manual J, 8th edition), performed by a licensed HVAC contractor. It uses local design temperatures from ASHRAE Fundamentals, window orientation, shading, a blower-door infiltration test, and duct losses — all factors a rule-of-thumb calculator cannot capture. Use the estimate above to understand the ballpark before getting a professional quote.
Want the full explanation of how heat pump sizing works? Read the heat pump sizing guide → Or compare with the rule-of-thumb BTU calculator and the more detailed heat loss calculator.
Reference & education only. Not professional, engineering, or code-compliance advice. Estimates are based on published model codes; local amendments and your Authority Having Jurisdiction (AHJ) govern. Always verify against the current adopted code and a licensed professional before doing work.
Last reviewed 2026-08.