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 tons and BTU/hr, instantly.
Your climate
UK, New Zealand, Pacific Northwest, Maritime Canada
Insulation quality
The heating load dominates at 37,500 BTU/hr. A 3.5-ton 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.