Tankless vs. Tank Water Heater: Which Is Worth It?
Which one to pick
A tank heater wins on upfront cost and simple installation — the right choice if budget is tight or you're doing a quick like-for-like swap. A tankless unit costs more (especially gas models that need venting and gas-line upgrades) but lasts about twice as long, never runs out of hot water, and trims energy bills. Over a 20-year horizon, tankless often comes out ahead — particularly for households with high or variable hot-water demand.
When your water heater dies — or you’re planning ahead — you’ll weigh a traditional storage tank against a tankless (on-demand) unit. They solve the same problem very differently, and the cheapest choice today isn’t always the cheapest over 20 years.
A tank heater is cheap to buy and simple to install, but it keeps 40–50 gallons hot around the clock (standby loss) and lasts only 8–12 years. A tankless unit heats water as you use it — endless hot water, ~20-year lifespan, lower energy bills — but costs more upfront, and gas models often need venting and gas-line upgrades. The table below lays out the trade-offs.
| Factor | Tank | Tankless |
|---|---|---|
| Installed cost | $600 – $3,100 | $1,400 – $5,600 |
| Lifespan | 8 – 12 years | ~20 years |
| Energy efficiency | Standby losses (keeps water hot) | Heats on demand; 8 – 34% more efficient |
| Hot water supply | Limited by tank size | Endless, but flow-rate limited |
| Space | Large floor unit | Compact, wall-mounted |
| Install complexity | Simple like-for-like swap | Often needs gas/venting/electrical upgrades |
| Best for | Lowest upfront cost, steady use | Long-term savings, space, high/variable use |
Common questions
- Is tankless cheaper than a tank water heater?
- No, not upfront — tankless runs $1,400–$5,600 installed versus $600–$3,100 for a tank. Tankless can be cheaper over its ~20-year life through energy savings and not needing replacement as often.
- How much can tankless save on energy?
- The U.S. Department of Energy estimates tankless units are 8–34% more efficient than tank heaters, with the biggest savings in lower-use households.
- Why is tankless installation more expensive?
- Beyond the pricier unit, gas tankless heaters often need a larger gas line, new stainless venting, and electrical work, which drives up the install cost.
- Which lasts longer?
- Tankless units last about 20 years versus 8–12 for a tank — roughly double, which factors into the long-term value.
How we estimate: We checked these prices against the 2026 sources listed below (see how we get our numbers). Your price depends on where you live, so get two or three written bids.
Sources
We checked the prices on this page against 2026 numbers from these sources: