A standard tank water heater is the cheapest to buy, a tankless model lasts longer and never runs out of hot water at its rated flow, and a heat pump water heater usually has the lowest operating cost if you currently heat water with electricity. For most households replacing a working gas tank, another gas tank or a tankless unit makes sense. For households with electric water heating, a heat pump water heater is often the best long-term value.
Quick answers
- Tank: lowest upfront cost, about 8–12 years of life, limited hot water supply.
- Gas tankless: endless hot water at its flow rate, often 20 years of life, higher install cost.
- Heat pump water heater: uses roughly a third to half the electricity of a standard electric tank.
- Switching from tank to gas tankless may require new gas lines and venting.
- Choose based on fuel available, household size and how long you’ll stay in the home.
Side-by-side comparison
| Factor | Gas tank | Electric tank | Gas tankless | Heat pump (hybrid electric) |
|---|---|---|---|---|
| Typical installed price | Low | Lowest | High | Medium to high |
| Operating cost | Medium | Highest | Lower than gas tank | Lowest of electric options |
| Typical lifespan | 8–12 years | 10–15 years | ~20 years | 10–15 years |
| Hot water supply | Limited by tank size | Limited by tank size | Unlimited at rated flow | Limited by tank size; slower recovery |
| Space | Large | Large | Small, wall-mounted | Large, needs surrounding air space |
| Maintenance | Flush yearly | Flush yearly | Descale yearly in hard water | Clean air filter, flush yearly |
Operating cost: how they compare
The DOE’s Uniform Energy Factor (UEF) on the yellow EnergyGuide label lets you compare efficiency directly. Higher UEF means lower operating cost:
- Standard gas tank: UEF often around 0.6–0.7
- Gas tankless: around 0.8–0.95
- Standard electric tank: around 0.9–0.95
- Heat pump water heater: often 3.0–4.0 or more
An electric heat pump water heater with a UEF of 3.5 uses roughly a quarter to a third of the electricity of a standard electric tank for the same hot water. The EnergyGuide label also shows estimated yearly operating cost.
10-year cost example
These are illustrative numbers for a family of four. Your costs will differ by prices and usage.
| Type | Installed price (example) | Yearly energy cost (example) | 10-year total |
|---|---|---|---|
| Gas tank, 50 gal | 2,000 USD | 350 USD | ~5,500 USD |
| Gas tankless | 4,000 USD | 270 USD | ~6,700 USD |
| Electric tank, 50 gal | 1,600 USD | 650 USD | ~8,100 USD |
| Heat pump, 50 gal | 3,500 USD | 220 USD | ~5,700 USD |
The tankless unit can come out ahead if it lasts 20 years and avoids a second tank replacement. The heat pump wins against a standard electric tank in most scenarios.
Tankless: pros and cons
Pros: endless hot water at its rated flow rate, small footprint, long life, no standby heat loss.
Cons: higher installation cost, may need a larger gas line and new venting, a short delay before hot water arrives, and limited flow if several showers run at once. Hard water requires regular descaling.
Heat pump water heaters: pros and cons
Pros: very low operating cost, dehumidifies and cools the space it’s in (a plus in garages and basements in warm climates).
Cons: taller and needs space for airflow (often around 700 cubic feet or ventilation), slower recovery in “heat pump only” mode, a fan noise similar to a dehumidifier, and less efficient in cold spaces.
Which should you choose?
| Your situation | Good choice |
|---|---|
| Gas available, tight budget | Gas tank |
| Gas available, staying 10+ years, high demand | Gas tankless |
| Electric only | Heat pump water heater |
| Small home, low usage, limited space | Small tank or point-of-use tankless |
| Large family, multiple simultaneous showers | Large tank or properly sized tankless |
Size it correctly first: What Size Water Heater Do I Need?
Frequently asked questions
Do tankless water heaters really save money?
They save on energy, but higher installation cost lengthens the payback. They make the most sense when they’re expected to last 20 years.
Can a heat pump water heater go in a closet?
Only if the closet has enough air volume or ventilation as specified by the manufacturer.
Is the federal tax credit still available?
The federal 25C credit ended for installations after December 31, 2025. See Heat Pump Tax Credit 2026.