Key takeaways
- Tank heaters cost less to buy and install, tankless usually costs more up front.
- Tankless heaters can last longer and take less space.
- Gas tankless units often need bigger gas lines and venting.
- Size either one to how much hot water you use at once.
How they work
A tank heater keeps 40 to 80 gallons hot all day, ready for when you need it, and loses a little heat even when nobody is home. A tankless heater heats water only as it flows through, so it never runs out of the stored supply but has a flow limit.
That flow limit is the important number. A tankless unit that is too small will give lukewarm water if the dishwasher, a shower and the washer all run at once.
Cost, space and lifespan
Tank heaters are less expensive to buy and usually less expensive to install. Tankless units cost more up front, may need a larger gas line, new venting or an electrical upgrade, and need yearly flushing in hard water. In return they often last about twenty years, compared with about ten for a tank, and they free up floor space.
Efficiency depends on how much hot water you use. A household that uses a lot saves more with tankless, and a household that uses little may never earn back the extra cost.
How to decide
Choose a tank if you want the lowest up-front cost, have simple venting and use moderate amounts of hot water. Choose tankless if you have a large family, limited space or plan to stay long enough to earn back the cost. A heat pump water heater is a third option for electric homes with space to spare.
Our Water Heater Sizer shows a size and a rough payback for your household, and a plumber can confirm it on a visit to your Nashville home.
Related services
Quick answers
How long does a tank water heater last?
Most last about eight to twelve years, depending on water quality and maintenance.
Do tankless water heaters need maintenance?
Yes. Flushing them about once a year removes scale and keeps them running well, especially in hard water.
Ready to talk it through? Get a free estimate or call 615-431-3789.