Heat Pump Water Heater Cost & Savings Calculator
Compare a heat pump water heater (HPWH) to your current electric-resistance or gas tank on annual operating cost and simple payback.
The short answer
A heat pump water heater (HPWH) typically cuts annual water-heating cost by 60% to 75% vs an electric-resistance tank, saving a 3-person household roughly $400 to $500 per year and paying back its higher upfront cost in 1 to 3 years. Against cheap natural gas the savings are smaller — sometimes the gas tank is still cheaper to run — but a HPWH still beats an electric tank in every US market.
A heat pump water heater is a separate product from a space-heating heat pump — it's a tank water heater with a small heat pump on top that pulls heat from the surrounding air. You can have one without the other.
Annual operating cost
Heat pump water heater saves about $430/yr vs your electric resistance tank.
At an extra upfront cost of $600, simple payback is about 1.4 years on operating savings alone. Ignores future rate changes and any federal, state, or utility incentives.
Annual operating cost
Heat pump water heater
$150/yr
895 kWh · UEF 3.50
Electric resistance tank
$580/yr
3,404 kWh · UEF 0.92
Heads up on the install
- A heat pump water heater pulls heat from the surrounding air, so it gently cools and dehumidifies its space — ideal in a garage, basement, or utility room, less so in a small closet. Most manufacturers want at least ~700–1,000 cubic feet of air space around the unit.
- Switching from a gas tank usually means adding a dedicated 240V electrical circuit if you don't already have one near the water heater. Budget $300–$800 for that work on top of the install.
- A HPWH is a separate product from a space-heating heat pump. You can have one without the other.
These are ballpark estimates, not contractor quotes. Actual savings depend on your hot-water use, incoming water temperature, and your electricity and gas rates. A HPWH cools and dehumidifies the room it's in and needs adequate air space; switching from gas may require electrical work. Get written quotes from licensed plumbers or HVAC contractors before deciding.
How this calculator works
We estimate the annual hot-water energy your household needs, divide by each water heater's efficiency to get fuel input, then convert that input into the right physical unit (kWh for electric heaters, therms for gas) and multiply by your rate.
- Annual delivered hot-water energy = 18 gal/person/day × people × 365 days × 8.34 BTU/gal/°F × 65°F temperature rise. The 18 gal/person figure is the industry average for showering, dishwashing, laundry, and sinks combined; the 65°F rise reflects raising 55°F mains water to 120°F.
- HPWH input = delivered energy ÷ UEF ÷ 3,412.14 BTU/kWh. We use a Uniform Energy Factor of 3.5, the typical rating for current ENERGY STAR HPWHs.
- Electric-resistance tank input = delivered energy ÷ UEF ÷ 3,412.14 BTU/kWh. We use a UEF of 0.92, the typical rating for a standard electric tank.
- Gas tank input = delivered energy ÷ UEF ÷ 100,000 BTU/therm. We use a UEF of 0.62, the typical rating for a standard atmospheric gas tank. (Condensing gas tanks are rarer and rate higher.)
- Savings = current tank cost − HPWH cost. A negative number means the HPWH is more expensive to run at these rates, which can honestly happen with cheap gas plus expensive electricity.
- Simple payback = (HPWH installed cost − replacement cost of the current type) ÷ annual savings. Shown only when savings are positive. Ignores future rate changes and any federal, state, or utility incentives — the federal 25C tax credit alone covers 30% of HPWH cost up to $2,000.
Frequently asked questions
- How much does a heat pump water heater save?
- A heat pump water heater uses roughly one-quarter the energy of an electric-resistance tank to deliver the same hot water. For a typical 3-person household at $0.17/kWh, that's about $150 per year to run a HPWH vs about $580 for an electric tank — savings of roughly $400 to $500 per year. Larger households save more; smaller ones save less.
- Heat pump water heater vs electric tank — which is cheaper?
- The HPWH wins comfortably in every US market. A heat pump water heater has a Uniform Energy Factor (UEF) of about 3.5, meaning it delivers 3.5 units of hot-water energy per unit of electricity. An electric-resistance tank has a UEF around 0.92. Even after the HPWH's higher upfront cost (typically $600 more than an electric tank), simple payback is usually 1 to 3 years.
- Heat pump water heater vs gas tank — which is cheaper?
- It depends on your gas and electricity rates. A gas tank has a UEF around 0.62 and burns about 230 therms a year for a 4-person household — roughly $300/yr at $1.30/therm. A HPWH for the same household runs about $190/yr at $0.16/kWh. At those rates the HPWH saves about $100/yr with a 4 to 6 year payback. With very cheap gas or very expensive electricity, the gas tank can be the cheaper option to run.
- How long is the payback on a heat pump water heater?
- Replacing an electric-resistance tank: typically 1 to 3 years on operating savings alone. Replacing a gas tank: typically 4 to 8 years, depending on rates. These numbers ignore federal, state, and utility incentives — the federal 25C tax credit alone covers 30% of HPWH cost up to $2,000, which materially shortens payback for most households.
- Does a heat pump water heater need a 240V circuit?
- Yes — a standard 30A 240V circuit, same as an electric-resistance tank. If you're replacing an electric tank, your existing circuit usually works. If you're switching from a gas tank, you'll likely need an electrician to run a new 240V circuit to the water heater location. Budget about $300 to $800 for that electrical work depending on panel location and run length.
- Does a heat pump water heater cool the room?
- Yes. A HPWH pulls heat from the surrounding air to heat the water, so it gently cools and dehumidifies its space — usually 1,000 to 2,500 BTU/hr of cooling and noticeable dehumidification. This is a feature in a garage, basement, or utility room. In a small closet with no ventilation, the cooling can backfire by making the room too cold for the unit to run efficiently; most manufacturers want at least 700 to 1,000 cubic feet of air space around the unit.
Disclaimer:These are estimates for budgeting, not contractor quotes. Savings depend on your actual hot-water use, incoming water temperature, and your electricity and gas rates. A heat pump water heater cools and dehumidifies the room it's in and needs adequate air space; switching from gas may require electrical work. Get written quotes from licensed plumbers or HVAC contractors before deciding. HeatPumpLab is independently operated and not affiliated with any installer network.