Is a heat pump water heater worth it?

On running cost, usually yes and often dramatically so, because a UEF around 3.5 uses roughly a quarter of the electricity a resistance tank does. Whether it works for you turns on the installation: it needs about 700 cubic feet of surrounding air, a condensate drain, and a space you do not mind cooling slightly. In a tight conditioned closet it is the wrong appliance.

Does a tankless water heater pay for itself?

On energy alone, slowly. A condensing tankless unit at a 0.93 UEF against an atmospheric tank at 0.60 saves real money, but the upfront difference including a larger gas line and a new vent is often well over a thousand dollars. The stronger arguments for tankless are endless hot water, a longer service life and the floor space, not the fuel bill.

What should I include in the extra upfront cost?

Everything that differs between the two installations, not just the price of the box. For a heat pump water heater that means the condensate drain and any ducting. For a tankless unit that means the gas line upsizing, the vent, the isolation valves and often an electrical circuit. Those items routinely exceed the difference in appliance price.

Why does this ignore fuel price rises?

Because adding an escalation rate makes the answer look more precise while making it less reliable, since nobody knows future fuel prices. Simple payback is the honest form. If you want to account for rising prices, treat the figure this calculator gives as a ceiling: rising fuel prices shorten payback on the more efficient unit rather than lengthening it.

Running cost calculator

Water Heater Payback Calculator

Quick answer

Payback is the extra upfront cost divided by the annual saving. A heat pump water heater at $1,100 against a $550 resistance tank saves roughly $400 a year at typical use and electricity prices, which pays back the $550 difference in about 16 months.

Result

Simple payback 1.3 yr Published standard

Annual saving $440 Published standard

Current unit per year $597

New unit per year $157

Put the INSTALLED cost difference into the upfront figure, not the sticker difference. A heat pump water heater often needs a condensate drain and 700 cubic feet of surrounding air, and a tankless retrofit often needs a larger gas line and a new vent, and those are where the real difference sits.

The formula

Annual saving = cost at the old UEF - cost at the new UEF. Payback years = extra upfront cost / annual saving.

This is simple payback with no discount rate and no fuel price escalation, which is the honest way to present it: adding assumptions about future energy prices makes the number look more precise while making it less reliable. Note also that the upfront difference should include installation, and a heat pump water heater often costs more to install than it does to buy.

The figures above are computed with these exact inputs: Fuel, same for both electricResistance, Current unit UEF 0.92, New unit UEF 3.5, Fuel price per unit 0.16 $, Extra upfront cost 550 $, Hot water per day 55 gal, Temperature rise 70 F.

What this calculator assumes

Some of these are published test procedures or code tables and some are planning conventions. They are not the same kind of number, so each one is labeled.

Assumption	Kind	Where it comes from
DOE Uniform Energy Factor	Published standard	DOE Uniform Energy Factor, measured over a standard daily draw pattern and including standby loss
Doe Daily Draw: 55	Convention	Daily hot water use assumed for the annual cost figure. Actual household use varies widely and this is the input to change first
Water Weight: 8.33	Published standard	Published density of water at 60 F, 8.33 lb per gallon

Gear that matches this result

Every card below is in the page source. The calculator re-ranks them against your numbers and marks anything that falls short of what you just calculated.

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

Intermediate

ACiQ

ACiQ 50 Gallon Hybrid

$1,799.99

A hybrid runs its compressor most of the time and falls back to resistance elements on a heavy draw, which is why a hybrid never simply fails to make hot water.

Best for: Households unwilling to risk a slow recovery

Check price on Amazon

Expert

Rinnai

Rinnai REHP65 65 Gallon

$2,049.00

Going up a tank size is the standard fix for a heat pump water heater, because a larger tank lets the slower compressor do more of the work and the elements less.

Best for: Four people who do not want the elements running

Check price on Amazon

Expert

Rinnai

Rinnai REHP80 80 Gallon

$2,299.00

Eighty gallons is tall. Measure the ceiling height and the 700 cubic feet of air a heat pump water heater needs around it before this is on the list at all.

Best for: Large households with the room and the air volume

Check price on Amazon

Frequently asked questions

Is a heat pump water heater worth it?: On running cost, usually yes and often dramatically so, because a UEF around 3.5 uses roughly a quarter of the electricity a resistance tank does. Whether it works for you turns on the installation: it needs about 700 cubic feet of surrounding air, a condensate drain, and a space you do not mind cooling slightly. In a tight conditioned closet it is the wrong appliance.
Does a tankless water heater pay for itself?: On energy alone, slowly. A condensing tankless unit at a 0.93 UEF against an atmospheric tank at 0.60 saves real money, but the upfront difference including a larger gas line and a new vent is often well over a thousand dollars. The stronger arguments for tankless are endless hot water, a longer service life and the floor space, not the fuel bill.
What should I include in the extra upfront cost?: Everything that differs between the two installations, not just the price of the box. For a heat pump water heater that means the condensate drain and any ducting. For a tankless unit that means the gas line upsizing, the vent, the isolation valves and often an electrical circuit. Those items routinely exceed the difference in appliance price.
Why does this ignore fuel price rises?: Because adding an escalation rate makes the answer look more precise while making it less reliable, since nobody knows future fuel prices. Simple payback is the honest form. If you want to account for rising prices, treat the figure this calculator gives as a ceiling: rising fuel prices shorten payback on the more efficient unit rather than lengthening it.

Researched guidance, not professional advice. These results are planning figures from published test procedures, code tables and manufacturer specifications, and they do not replace a sizing done by the person who will sign the permit. A water heater is a pressure vessel: never cap, plug or remove the temperature and pressure relief valve, and replace one that will not open when the test lever is lifted. Gas line, flue and vent work belongs to a licensed plumber or gas fitter, because improper venting produces carbon monoxide. Water at 140 F scalds a child in seconds. Turn off the breaker before touching an element, and never energise an element that is not submerged.