Water Heater Cost Calculator
What your water heater actually costs to run each year, what a different type would cost instead, and how quickly an upgrade pays for itself.
Estimates for comparison. Real usage varies enormously with household habits, incoming water temperature, and thermostat setting. Heat pump water heaters also need adequate air volume and a condensate drain — confirm placement with an installer before buying.
Electric tankless is nearly 100% efficient at the unit — every watt becomes heat. That still doesn't make it cheap, because electricity costs far more per BTU than gas.
Used to size the unit, not the yearly bill.
Winter inlet temperature is what decides whether the unit can keep up.
Heat pump water heaters commonly run $3,000–$5,000 installed; enter the extra over a like-for-like replacement if you're replacing a dead unit anyway.
The 25C credit expired. The One Big Beautiful Bill Act ended it for equipment placed in service after December 31, 2025. A 2026 install gets no federal credit — but many state and utility programs still offer heat-pump water heater rebates, often several hundred dollars, so check yours before ruling it out.
Switching saves
Choose your household size
| Detail | Amount |
|---|---|
| What you run now | — |
| Heat pump water heater | — |
| Net cost after credit | — |
| Simple payback | — |
| Hot water used | — |
| Electrical service needed | — |
What Does a Replacement Cost?
The calculator above shows running costs. This is the up-front number — what it costs to put a new unit in, and how much of that is the plumber rather than the appliance.
These assume a like-for-like swap. Switching fuel or format — tank to tankless, electric to gas — adds venting, gas line, or electrical work that can double the labor.
Installed cost
Pick a type
| Line item | Amount |
|---|---|
| Unit | — |
| Installation labor | — |
National ranges for planning. Emergency same-day replacement after a leak costs more than a planned swap — one more reason to replace a tank before it fails.
Water heater replacement cost in 2026
| Type | Installed | Labor portion | Typical life |
|---|---|---|---|
| Electric tank | $900–1,800 | $150–450 | 10–15 years |
| Gas tank | $1,000–2,200 | $200–600 | 8–12 years |
| Heat pump (hybrid) | $1,800–4,000 | $400–1,200 | 13–15 years |
| Electric tankless | $1,400–3,500 | $500–1,500 | 20+ years |
| Gas tankless | $2,500–5,600 | $600–1,850 | 20+ years |
What drives the price
- Like-for-like is always cheapest. Same fuel, same format, same spot: the plumber drains, disconnects, swaps, reconnects. Conversions are where the money goes.
- Tank to tankless is a bigger job than it sounds. Gas tankless usually needs a larger gas line and new stainless venting; electric tankless can need 100+ amps of new service — sometimes a panel upgrade costing thousands on its own. The calculator above shows the amperage so you can check this before you shop.
- Heat pump water heaters need space and warmth. They pull heat from the surrounding air, want roughly 700–1,000 cubic feet around them, and blow cold air out — great in a garage in Georgia, awkward in a closet in Minnesota.
- Code upgrades ride along. Expansion tanks, seismic strapping, drip pans, and updated venting are often required at replacement even if the old unit didn't have them.
- Permits are normal and worth having. Most jurisdictions require one for a water heater; an unpermitted swap can surface later during a home sale.
How Water Heating Cost Is Calculated
- Hot water used ≈ 14 gallons per person per day, plus a small base.
- Heat needed = gallons × 8.34 lb × 70°F rise × 365. Raising water from ~55°F to ~125°F is the standard assumption.
- Energy bought = that heat ÷ UEF. This is where the types separate — a heat pump's UEF above 1.0 isn't magic, it just moves heat that already exists in the air.
- Cost = energy × your rate, and payback = net cost after credit ÷ annual saving.
Worked example — 4 people, $0.17/kWh, electric tank at 0.90 UEF → heat pump at 3.5: 4,441 kWh/yr becomes 1,142 kWh/yr, cutting $755 down to $194. That's about $561 saved a year. A $2,400 unit now pays back in roughly 4 years at full price — it was closer to 3 while the federal credit existed, and a state or utility rebate can still bring it back down.
Annual Running Cost by Type
Household of four, $0.17/kWh electricity and $1.60/therm gas:
| Type | UEF | Yearly cost | Notes |
|---|---|---|---|
| Electric tank | 0.90 | ~$755 | The expensive baseline |
| Gas tank | 0.64 | ~$341 | Cheap to run where gas is cheap |
| Gas tankless | 0.80 | ~$273 | No standby loss; higher install |
| Electric tankless | 0.98 | ~$693 | Efficient at the unit, expensive to run; huge electrical demand |
| Heat pump | 3.5 | ~$194 | Cheapest to run; needs air space |
When It Pays and When It Doesn't
- Replacing an electric tank — still one of the strongest cases in home energy. Roughly a third of the electricity and $500–$600 a year saved. Payback stretched to about 4–6 years when the federal credit ended, and a state or utility rebate pulls it back toward 3.
- Replacing cheap natural gas — usually not worth it on running cost alone. The gap is small and the install is expensive.
- Buy at replacement time, not before. If your tank is dying anyway, compare the extra cost over a like-for-like swap — that's the real number, and it shortens payback dramatically.
- Location matters. A heat pump water heater cools and dries the room it's in. Garage or basement: fine, often welcome. Inside heated space in a cold climate: it steals heat your furnace replaces, eroding savings.
- Size up when switching. Recovery is slower than resistance elements — many installers go one tank size larger, or pick a model with a hybrid boost mode.
The Electric Tankless Trap
Electric tankless heaters are marketed on efficiency, and the number is genuinely excellent — about 0.98 UEF, because essentially every watt becomes heat. It's easy to read that and assume it's the cheap option. It usually isn't, for two separate reasons.
Efficiency isn't price. Electricity costs far more per unit of heat than natural gas in most of the country. A 0.98-efficient electric unit and a 0.64-efficient gas tank can deliver identical hot water while the electric one costs roughly double to run. Efficiency tells you how little energy is wasted, not how much the energy costs.
The bigger problem is your electrical panel. Heating water instantly takes an enormous amount of power. The physics is fixed:
kW = GPM × temperature rise (°F) × 0.1466
A single shower at 2.5 GPM with 55°F water coming in needs about 26 kW — roughly 110 amps at 240 V, or three 40-amp double-pole breakers. Plenty of homes have 100- or 150-amp service in total. Where winter inlet water drops to 40°F, the same shower needs closer to 31 kW.
That's why the calculator shows the electrical requirement alongside the running cost: a service upgrade commonly runs $2,000–$4,000 and can dwarf the price of the heater. Switch to the Electric Tankless tab and change the inlet temperature to see how quickly it escalates in a cold climate.
Where electric tankless does make sense: point-of-use — a single remote sink, a workshop, a guest bath far from the tank. Small units draw a fraction of the power and save the standing loss of a long hot-water run. As a whole-house solution in a cold climate, it's usually the wrong tool.
Frequently Asked Questions
What does a water heater cost to run?
Family of four: ~$755/yr electric tank, ~$341 gas tank, ~$194 heat pump, at $0.17/kWh and $1.60/therm.
Is a heat pump water heater worth it?
Replacing electric resistance, usually — $350–$450/yr saved, paying back in about 4–6 years now that the 30% federal credit has ended (it was 2–4 with it). State and utility rebates still help. Replacing cheap gas, usually not.
What is UEF?
Uniform Energy Factor, on the EnergyGuide label. Electric ~0.90, gas tank ~0.60, gas tankless ~0.80, heat pump 3.0–4.0.
Is tankless cheaper to run?
Gas tankless: about 25% less than a gas tank, but install is often double — payback on running cost alone can exceed a decade. Electric tankless is a different story; see below.
Is electric tankless cheaper than an electric tank?
Only slightly. You save the standby loss (0.98 vs 0.90 UEF, roughly 8%), but you're still paying electricity rates for every drop. It is not close to a heat pump water heater, which delivers the same hot water for about a quarter of the energy.
What size breaker does an electric tankless need?
A whole-house unit typically needs 27–36 kW — around 110–150 amps at 240 V, or three to four 40-amp double-pole breakers. Many homes don't have the spare service capacity, and an upgrade runs $2,000–$4,000.
Does it cool the room?
Yes, and dehumidifies it. Fine in a garage or basement; costly inside heated space in winter. Needs ~700–1,000 cu ft of air.
What size do I need?
40 gal for 1–2, 50 for 3–4, 65–80 for 5+. Consider sizing up one step when switching to a heat pump.
Will my existing gas line support a tankless unit?
Not necessarily. A tank heats slowly over hours, so a 3/4″ line that's fine for it can be undersized for a tankless unit, which draws its full BTU/hr instantly on demand. Have a plumber check line size specifically, not just whether gas service reaches the location.
Will old or narrow pipes limit my hot water even with the right size heater?
Yes — this calculator sizes the unit for the GPM your fixtures demand at the heater, but older 1/2″ branch lines can bottleneck flow before it reaches the tap. Sizing the heater correctly doesn't fix a pipe that was already the limiting factor.
References
- ENERGY STAR — certified water heaters (UEF ratings by type): energystar.gov
- ENERGY STAR — heat pump water heaters and federal tax credits: energystar.gov
- US Energy Information Administration — residential energy prices: eia.gov