Plumbing · Materials and methods · Updated November 2026
Tank vs. Tankless Water Heaters
A tank water heater keeps a supply of hot water ready. A tankless unit heats water only when you turn on the tap. Tankless costs more up front and can need gas, venting or electrical upgrades, but it does not run out of hot water.
Side by side
| Tank | Tankless | |
|---|---|---|
| Installed cost | $600–$2,500 (like for like) | $1,400–$3,900 (switching from a tank) |
| Hot water supply | Limited by tank size; recovers over time | Continuous, but limited by flow rate |
| Space | Large footprint | Wall-mounted, compact |
| Standby heat loss | Yes, keeps the tank hot | No |
| Installation changes | Usually none for a like-for-like swap | Often a larger gas line, new venting, or heavy electrical circuits for electric units |
| Maintenance | Drain sediment periodically | Descale periodically, especially with hard water |
Installed costs from our plumbing cost guide.
When tankless makes sense
- You regularly run out of hot water with your current tank.
- You have gas service with capacity for a larger line, or space and electrical capacity for an electric unit.
- You plan to stay long enough for energy savings to offset the higher cost.
- You need to free up floor space.
When a tank is the better choice
- You want the lowest upfront cost and a quick replacement.
- Your home would need major gas or electrical upgrades for tankless.
- Several showers and appliances often run at once and a tankless unit would need to be very large.
A heat pump water heater (a tank type that uses electricity very efficiently) is another option in many homes. Ask your plumber.
Cost figures are national ranges from the sources listed in our plumbing cost guide, not a quote from FixFinch or any contractor. Calls connect you with an independent service provider in our network. FixFinch is not a contractor and does not perform the work.