Tankless Water Heater Installation Cost Calculator
Tankless water heater installation cost depends on the fuel and on how much of the old setup has to change. Replacing a tank often means a bigger gas line and new venting for a gas unit, or a new circuit and sometimes a panel upgrade for an electric one. The calculator above prices each type with installation and adds those changes separately.
Fuel, size and the change-over work
Pick a natural gas, propane or electric unit for the whole house, or a small electric unit for one sink or shower.
Extras cover the permit, removing the old water heater, upgrading the gas line, new venting, a new electrical circuit and a panel upgrade.
Tank or tankless, side by side
A tankless unit costs roughly twice as much to put in as a tank, and lasts about twice as long. Tankless water heater installation cost runs $1,200 to $3,500, with an average of about $2,800, against $800 to $1,500 for a traditional tank water heater. A tankless unit typically lasts 15 to 20 years and a tank 8 to 12.
| Tank | Tankless (gas) | Tankless (electric) | |
|---|---|---|---|
| Installed price | $800 to $1,500 | $1,650 to $3,500 | $650 to $2,500 |
| Running cost per year | $440 to $580 | $192 to $264 | $300 to $540 |
| Lifespan | 8 to 12 years | 15 to 20 years | 15 to 20 years |
At these numbers a gas unit saves about $180 to $390 a year over a tank, so the extra $850 to $2,000 up front takes roughly 2 to 11 years to earn back.
Tankless units need one thing tanks mostly do not: descaling, which costs $100 to $500 a year.
Tankless water heater installation cost by fuel
The installed price splits into the unit and the labor.
| Fuel | Unit | Installation | Total |
|---|---|---|---|
| Natural gas | $750 to $2,000 | $900 to $1,500 | $1,650 to $3,500 |
| Propane | $500 to $2,000 | $900 to $1,500 | $1,400 to $3,500 |
| Electric | $500 to $1,500 | $150 to $1,000 | $650 to $2,500 |
Plumbers charge $75 to $150 an hour and the job takes four to eight hours. An electric tankless water heater is cheaper to install, though a whole-house model can need new circuits or a panel upgrade, listed below.
Sizing the unit by flow rate
Tankless heaters are sized by how many gallons per minute (GPM) of hot water they can deliver at once, not by tank volume. Unit prices by size:
| Size | Typical use | Unit price |
|---|---|---|
| 1 to 2 GPM | point-of-use, one sink or shower | $150 to $500 |
| 2 to 4 GPM | small household | $500 to $1,000 |
| 5 to 7 GPM | medium household | $1,000 to $2,000 |
| 8 to 10 GPM | several bathrooms running together | $1,500 to $3,000 |
A small household may need only 2 to 3 GPM, while larger homes can need 8 to 10, by typical estimates. A point-of-use unit for a single sink or shower is the cheapest option in the calculator, but it does not replace a whole-house heater.
Switching from a tank: what gets added
Replacing an old tankless unit with a new one is the simple job. A like-for-like swap costs about $1,400 to $3,900, while a tank-to-tankless conversion runs $2,200 to $5,600 or more.
The difference is the house itself. Gas tankless water heater installation cost rises when the gas line has to be upsized and new venting run. Electric units may need new circuits or a bigger panel.
| Conversion work | Cost |
|---|---|
| Gas line upgrade | $400 to $800 |
| New venting | $400 to $800 |
| New electrical circuit | $200 to $600 |
| Electrical panel upgrade | $1,000 to $2,000 |
| Permit | $50 to $200 |
| Removing the old heater | $100 to $500 |
The calculator includes the permit and removal by default. If you are replacing a tank, turn on the gas line and venting for a gas unit, or the circuit and possibly the panel for an electric one.
The tax credit is gone for 2026
Until the end of 2025, a gas tankless heater with a uniform energy factor of 0.95 or higher qualified for a federal credit of 30%, up to $600, according to ENERGY STAR. The IRS says that credit is not allowed for property placed in service after December 31, 2025. Some price guides still mention it, so do not count on it in this year’s tankless water heater cost. Utility rebates of $100 to $300 may still apply where you live.