Heat Pump Efficiency Calculator

COP (coefficient of performance) is an instantaneous, lab-bench number: heat delivered divided by electricity in, both in the same units. A COP of 3.5 means you get 3.5 kWh of heat for every 1 kWh of electricity. HSPF (heating seasonal performance factor) is a seasonal average measured under the AHRI 210/240 test, expressed in BTU per watt-hour. To convert it to a seasonal COP, divide by 3.412 (the BTU-to-Wh constant): an HSPF of 9 equals a seasonal COP of about 2.64, and an HSPF of 11 (cold-climate models) equals about 3.22. HSPF is the more honest field number because it already bakes in defrost losses, part-load cycling, and the test's mix of mild and cold hours. The calculator blends both signals and then derates for your climate zone.

Air-source systems usually have lower installation cost because they do not need a ground loop. Ground-source systems can provide more stable source temperatures, but site conditions, drilling or trenching, load, distribution, and local prices drive the result. Get a Manual J load calculation and local quotes; the calculator estimates operating energy only.

Air-source performance changes with outdoor conditions. The calculator applies a climate multiplier as a planning assumption; it does not model a specific unit's capacity, defrost behavior, or backup heat. Use the AHRI rating and manufacturer performance data at the local design temperature, then have a qualified contractor size the system from a Manual J load.

It depends on your local electricity rate, gas price, climate, and equipment performance. The calculator uses your rates, assumed seasonal COP, and AFUE to compare fuel use. Do not treat its defaults as current price projections; compare local tariffs and the selected equipment's published performance.

Federal Sections 25C and 25D do not cover qualifying property placed in service or expenditures made after December 31, 2025 under current law. Do not apply the former federal credits to a 2026 installation. State, utility, and income-qualified rebate programs vary by location, funding, equipment, and installation date, so verify them before signing a contract.