Tank vs tankless vs heat pump, with operating cost and payback
4,600 kWh-equivalent per year reflects a typical 3–4 person household. Roughly 1,000 kWh-eq per person is a sane adjustment.
Leave UEF blank to use type defaults: gas tank 0.64, electric tank 0.92, gas tankless 0.90, electric tankless 0.96, heat pump 3.5. Check the yellow EnergyGuide label and enter your unit's real UEF for accuracy.
| Type | Installed Cost | Typical UEF | Operating Cost/yr* | Lifespan |
|---|---|---|---|---|
| Electric tank | $1,200 – $2,600 | 0.90 – 0.95 | ~$875 | 10–13 yrs |
| Gas tank | $1,700 – $3,200 | 0.60 – 0.70 | ~$405 | 10–13 yrs |
| Gas tankless | $3,000 – $6,500 | 0.85 – 0.96 | ~$288 | 15–20 yrs |
| Electric tankless | $1,200 – $5,800 | 0.96 – 0.99 | ~$838 | 15–20 yrs |
| Heat pump hybrid | $2,500 – $5,000 | 3.0 – 3.8 | ~$230 | 12–15 yrs |
*At 4,600 kWh-equivalent of delivered hot water a year, $1.65/therm gas, $0.175/kWh electricity, using the UEF defaults listed above. Installed ranges from published 2025–26 plumbing cost guides; wide electric-tankless spread reflects possible panel upgrades.
Water heater math has two halves: what you pay at install, and what you pay every month after. The second half is where most buyers get steered wrong, because an enthusiastic tankless pitch rarely shows the 20-year payback line. This calculator runs both halves using the same physics the EnergyGuide label uses.
Annual operating cost = hot water energy ÷ UEF × energy price. For gas models the energy unit is therms (1 therm = 29.3 kWh), so therms = kWh-equivalent ÷ UEF ÷ 29.3, then multiplied by your gas price. For electric models it's kWh ÷ UEF × electric price. UEF, the uniform energy factor, measures how much of the fuel actually lands in your hot water; anything above 1.0 for a heat pump means it's moving heat rather than making it.
Set your energy prices from a recent bill (the national averages of about $1.65 a therm and $0.175 a kWh are loaded as defaults). Adjust household size on the usage line. Pick any two heater types to compare; if you know the exact UEF from the spec sheet or EnergyGuide label, enter it in the third field and it applies to heater B.
A family of four using 4,600 kWh-equivalent a year, with gas at $1.65 a therm. A gas tank at UEF 0.64 burns 4,600 ÷ 0.64 ÷ 29.3 = 245 therms, costing $405 a year. The tankless at UEF 0.90 burns 174 therms, or $288. That's $117 a year saved. Against a $2,300 upfront premium (midpoints of $4,750 and $2,450), the tankless pays back in 19.7 years, right at the edge of its own lifespan. Efficient? Yes. A slam-dunk investment on gas? Not really.
Run the same family on electricity and the story flips. An electric tank at UEF 0.92 draws 5,000 kWh, costing $875 a year at $0.175. A heat pump hybrid at UEF 3.5 needs only 1,314 kWh, or $230. The $645 annual difference retires the roughly $1,850 purchase premium in 2.9 years, and over a 13-year life the heat pump's total cost of ownership comes to about $6,740 against $13,275 for the tank. If your water heater is electric, the hybrid is the whole conversation.
Installed nationally, a gas tank water heater runs $1,700 to $3,200 and an electric tank $1,200 to $2,600. Gas tankless jumps to $3,000 to $6,500 because of venting and gas-line work, electric tankless spans $1,200 to $5,800 depending on your panel, and heat pump hybrids run $2,500 to $5,000. The unit itself is often under a third of the invoice.
Depends on your fuel. For gas, the premium is roughly $2,300 and typical savings about $117 a year, so payback approaches 20 years. For electric, the better upgrade is a heat pump hybrid: it saves about $645 a year over an electric tank and pays back in about 3 years.
A heat pump hybrid at UEF 3.0 to 3.8 moves heat instead of generating it, so a typical family's hot water drops from about 5,000 kWh a year with a resistance electric tank to roughly 1,300 kWh. At $0.175 per kWh that's about $645 a year saved, and the roughly $1,850 premium over an electric tank pays back in under 3 years.
A 50-gallon gas tank or a 65-to-80-gallon electric tank covers a family of 4; gas recovers about twice as fast, so it needs less stored volume. For tankless, target 6 to 7 GPM in a cold-winter climate and 7 to 9 GPM where inlet water is milder, accounting for simultaneous showers plus a dishwasher.
Tank models average 10 to 13 years; the anode rod gives out first and tank leaks follow. Tankless units last 15 to 20 years but need annual descaling in hard water. Heat pump hybrids fall in between at 12 to 15 years. Flushing sediment yearly is the cheapest life-extender there is.
A whole-house electric tankless draws 100 to 150 amps at 240V, more than many 200-amp panels have spare. If your panel needs an upgrade or a service bump to 300 or 400 amps, that electrical work can cost more than the heater itself, which is why installed quotes range from $1,200 to $5,800.