What does a heat pump water heater cost to run per year?

About $294 at $0.30 per kWh, heating 55 gallons a day through a 70 F rise at a 3.5 UEF. Your own figure moves most with daily hot water use, which varies far more between households than efficiency does between units in the same category.

What is UEF and where do I find it?

UEF is the DOE Uniform Energy Factor, the ratio of hot water energy delivered to energy consumed, measured over a standard daily draw pattern. It is printed on the yellow EnergyGuide label and in the specification sheet. Because the test runs a whole day it already includes standby loss through the tank walls.

Why is a heat pump UEF above 1?

Because a heat pump water heater does not create heat, it moves heat. It takes warmth out of the surrounding air and puts it into the water, so it delivers more heat energy than the electricity it consumes. Typical units land between 3.0 and 4.0, which is roughly a quarter of the running cost of a resistance element.

Does a bigger tank cost more to run?

A little, through standby loss, but far less than people expect on a modern foam insulated tank. The energy to heat the water you actually use dominates the bill, and that is the same whatever size the tank is. Standby loss is a reason not to buy a much larger tank than you need, not a large number on its own.

What is the cheapest way to reduce this bill?

In order: use less hot water, insulate the first stretch of hot outlet pipe, lower the setpoint if the scald and Legionella tradeoff allows it, and only then consider a more efficient heater. The first two cost almost nothing and work immediately, while the last one has a payback measured in years.

Running cost

What Does a Heat pump water heater Cost to Run at $0.30 per kWh?

Researched from the DOE test procedures, NFPA 54 and NEC code tables, and manufacturer specifications. Updated 2026-09-17.

Quick answer

A heat pump water heater at a typical 3.5 UEF, heating 55 gallons a day through a 70 F rise, costs about $294 a year at $0.30 per kWh. That is 980 kWhs a year, or about $0.81 a day.

Water heating is usually the second largest energy use in a house after space conditioning, and almost all of the variation between households comes from two numbers: how much hot water they use and what their fuel costs.

This page holds the usage at 55 gallons a day through a 70 F rise and the efficiency at a 3.5 UEF, then reads the cost at $0.30 per kWh: about $294 a year.

Where the figure comes from

Annual running cost build-up, heat pump water heater
Step	Figure
Hot water per day	55 gal
Temperature rise	70 F
Heat delivered per day	32,071 BTU
UEF	3.5
Energy input per year	3,344,495 BTU
kWhs per year	980
Price per unit	$0.30
Cost per year	$294

Published standard Source: DOE Uniform Energy Factor as the divisor on delivered energy, with published energy content per fuel unit. UEF is measured over a standard daily draw pattern and already includes standby loss, which is why it is always lower than a burner thermal efficiency.

How heat pump water heater compares at this price

Every heater type at its typical UEF, on the same 55 gallons a day and the same 70 F rise. Fuel prices differ between these, so this is a comparison of efficiency rather than of bills.

Annual cost by heater type at typical UEF
Heater type	Typical UEF	Energy per year	Unit
Electric resistance tank	0.92	3,729	kWh
Heat pump water heater	3.5	980	kWh
Atmospheric gas tank	0.6	195	therm
Condensing gas tank	0.8	146	therm
Condensing gas tankless	0.93	126	therm
Propane tank	0.6	213	gallon of propane

Published standard Source: DOE UEF figures typical of each category, applied to the same delivered energy. Multiply the energy column by your own fuel price to get a comparable bill. A heat pump UEF above 1 is not an error: it moves heat rather than making it.

The same heater across the price range

Heat pump water heater annual cost by fuel price
Price per kWh	Cost per year	Cost per day
$0.12	$118	$0.32
$0.16	$157	$0.43
$0.22	$216	$0.59
$0.30	$294	$0.81

Published standard Source: The same energy calculation at each price point. Fuel prices vary regionally by more than efficiency does between units in the same category, which is why a general answer about the cheapest fuel is not worth much.

The input to change first

Gallons per day, every time. This page assumes 55, which is a planning convention rather than a measurement of your house, and household hot water use varies more than any other input here. A two person household using 30 gallons a day pays close to half this figure for the same heater at the same price.

Put your own numbers into the operating cost calculator, and if you are weighing an upgrade, the payback calculator compares two UEFs directly.

Units in this category, and the cheapest efficiency upgrade there is

Foam sleeve on the first six feet of hot outlet pipe is the best value item on this entire site. It costs less than ten dollars, needs nothing switched on, and cuts the fastest standing heat loss on the system.

Beginner

Senville

Senville Hybrid Heat Pump 50 Gallon

$1,099.99

The lowest price of entry into a heat pump water heater in this catalog, and Energy Star listed, which means its efficiency figure was measured against the DOE test procedure rather than claimed.

Best for: A first heat pump water heater in a warm garage or basement

Check price on Amazon

Intermediate

Rinnai

Rinnai REHP50 50 Gallon

$1,799.00

A 50 gallon heat pump tank from a manufacturer with an established residential service channel, which is the part that decides what year eight looks like.

Best for: The standard 50 gallon replacement, done properly

Check price on Amazon

Beginner

Frost King

Frost King SP57 R10 Blanket, 48 x 75 in

$32.54

R10 stated on the package, which is the only number worth comparing between blankets. Many listings publish none.

Best for: An older tank that is warm to the touch

Check price on Amazon

Frequently asked questions

What does a heat pump water heater cost to run per year?: About $294 at $0.30 per kWh, heating 55 gallons a day through a 70 F rise at a 3.5 UEF. Your own figure moves most with daily hot water use, which varies far more between households than efficiency does between units in the same category.
What is UEF and where do I find it?: UEF is the DOE Uniform Energy Factor, the ratio of hot water energy delivered to energy consumed, measured over a standard daily draw pattern. It is printed on the yellow EnergyGuide label and in the specification sheet. Because the test runs a whole day it already includes standby loss through the tank walls.
Why is a heat pump UEF above 1?: Because a heat pump water heater does not create heat, it moves heat. It takes warmth out of the surrounding air and puts it into the water, so it delivers more heat energy than the electricity it consumes. Typical units land between 3.0 and 4.0, which is roughly a quarter of the running cost of a resistance element.
Does a bigger tank cost more to run?: A little, through standby loss, but far less than people expect on a modern foam insulated tank. The energy to heat the water you actually use dominates the bill, and that is the same whatever size the tank is. Standby loss is a reason not to buy a much larger tank than you need, not a large number on its own.
What is the cheapest way to reduce this bill?: In order: use less hot water, insulate the first stretch of hot outlet pipe, lower the setpoint if the scald and Legionella tradeoff allows it, and only then consider a more efficient heater. The first two cost almost nothing and work immediately, while the last one has a payback measured in years.

Researched guidance, not professional advice. These figures come from published test procedures, code tables and manufacturer specifications, and they are planning numbers rather than a sizing done for your house. Where a manufacturer publishes a figure for the unit in front of you, that figure governs over anything computed here.