Heat Pump Sizing Calculator
Calculate the right heat pump size for your home and see estimated annual savings compared to a gas furnace.
Enter your home details to get heat pump sizing recommendations.
How Heat Pumps Work
A heat pump is an electrically powered device that transfers heat between indoors and outdoors. In cooling mode, it works exactly like an air conditioner -- extracting heat from inside your home and releasing it outside. In heating mode, it reverses the process, extracting heat from outdoor air (even in cold temperatures) and moving it inside. Because a heat pump moves heat rather than generating it by burning fuel, it can deliver 2 to 4 times more heating energy than the electricity it consumes. This ratio is called the Coefficient of Performance (COP). A COP of 3.0 means that for every 1 kWh of electricity used, the heat pump delivers 3 kWh of heating energy.
SEER and HSPF Ratings Explained
Heat pump efficiency is measured by two key ratings. SEER (Seasonal Energy Efficiency Ratio) measures cooling efficiency -- higher SEER means lower electricity bills during summer. HSPF (Heating Seasonal Performance Factor) measures heating efficiency -- higher HSPF means lower heating costs in winter. In hot climates (Zones 1-2), prioritize high SEER (18-20+) since you will run in cooling mode most of the year. In cold climates (Zones 5-7), prioritize high HSPF (10-12) since heating performance matters more. Our calculator recommends optimal SEER and HSPF based on your climate zone.
When Heat Pumps Beat Gas Furnaces
Heat pumps are most cost-effective when electricity is cheap relative to natural gas. The break-even point depends on your local utility rates and climate. In mild climates (Zones 1-4), heat pumps almost always save money because they rarely need supplemental electric resistance heating. In cold climates (Zones 5-7), modern cold-climate heat pumps can operate efficiently down to -15 degrees F, but may need backup heating on the coldest days. The savings calculation above compares a heat pump to a 92% efficient gas furnace using your local electricity and gas rates.
Cold Climate Heat Pumps
Traditional heat pumps lose efficiency as outdoor temperatures drop below 40 degrees F. Modern cold-climate models (sometimes called "hyper-heat" or "low-ambient" systems) use variable-speed inverter compressors to maintain high efficiency down to -15 degrees F or lower. If you live in Zones 5-7, look for units with rated heating capacity at 5 degrees F and a low-temperature cutoff at or below -15 degrees F. Brands like Mitsubishi Hyper-Heat, Daikin Fit, and Carrier Greenspeed are designed specifically for cold climates.
Frequently Asked Questions
What size heat pump do I need?
A general rule is 25 BTU per square foot, adjusted for climate and insulation. A 2,000 sq ft home in a moderate climate typically needs a 3-4 ton heat pump (36,000-48,000 BTU). Our calculator factors in climate zone multipliers and insulation quality for a more accurate estimate. Always have an HVAC contractor perform a Manual J load calculation for final sizing.
Are heat pumps worth it in cold climates?
Yes, with the right equipment. Cold-climate heat pumps maintain a COP of 2.0-2.5 even at 5 degrees F, meaning they deliver 2-2.5x more heat energy than the electricity they consume. Combined with federal tax credits (up to $2,000 under the Inflation Reduction Act) and state rebates, the payback period is typically 5-8 years in most cold-climate states.
What is COP and how does it relate to HSPF?
COP (Coefficient of Performance) is the instantaneous ratio of heat output to electricity input. HSPF (Heating Seasonal Performance Factor) is the seasonal average, accounting for varying outdoor temperatures, defrost cycles, and supplemental heating. To convert: COP = HSPF / 3.412. An HSPF of 10 equals a seasonal COP of about 2.93, meaning the heat pump delivers nearly 3x more heat energy than electricity consumed.
What federal incentives are available for heat pumps?
The federal 25C tax credit (part of the Inflation Reduction Act) offers up to $2,000 for qualifying heat pump installations. Heat pumps must meet Energy Star requirements (typically SEER2 16+ and HSPF2 9.5+ for split systems). Many states offer additional rebates ranging from $500 to $5,000. Check the DSIRE database for incentives in your state.