Cost to run a electric tankless water heater
Water heating · typical wattage 18,000 W (8,000 W-36,000 W)
A electric tankless water heater draws about 8,000 W-36,000 W (typically 18,000 W). Run 1 hours a day, it uses about 6,570 kWh/year, which costs roughly $102/month and $1,219/year at the US average residential rate of 18.56¢/kWh (March 2026). At a high-rate state like California (33.35¢) it costs more; at a low-rate state like Washington (14.40¢) it costs less.
Source: U.S. DOE — Estimating Appliance and Home Electronic Energy Use. Data as of June 2026.
Electric tankless water heater at a glance
| Figure | Electric tankless water heater |
|---|---|
| Typical running wattage | 18,000 W (8,000 W-36,000 W) |
| Assumed usage | 1 h/day, 365 days/yr |
| Energy used | 6,570 kWh per year |
| Cost per month @ 18.56¢ | $102 |
| Cost per year @ 18.56¢ | $1,219 |
Source: U.S. DOE — Estimating Appliance and Home Electronic Energy Use; ENERGY STAR product specifications. Data as of June 2026.
Cost at light, typical and heavy use
How the monthly and yearly cost changes with how long you run it, at the US average 18.56¢/kWh:
| Usage | Cost / month | Cost / year |
|---|---|---|
| Light use (1 h/day) | $100 | $1,219 |
| Typical use (1 h/day) | $100 | $1,219 |
| Heavy use (2 h/day) | $200 | $2,439 |
Cost at different state rates
The same electric tankless water heater at typical usage, priced at a few representative state rates:
| Rate | Cost / month | Cost / year |
|---|---|---|
| US average (18.56¢) | $102 | $1,219 |
| Washington (14.40¢) | $77.76 | $946 |
| Texas (16.39¢) | $88.51 | $1,077 |
| California (33.35¢) | $180 | $2,191 |
Source: EIA Electric Power Monthly, Table 5.6.A (residential) (March 2026). Data as of June 2026.
Use the calculator to price it at your exact rate, or see all 51 states.
Wattage source & how to save
Whole-home electric tankless units draw a very high 8–36 kW, but only while hot water is flowing.
Tip to cut the cost: Tankless avoids standby losses, but the huge instantaneous draw needs a heavy dedicated circuit.
Frequently asked questions
How much does it cost to run a electric tankless water heater?
At the US average residential rate of 18.56¢/kWh, a electric tankless water heater (about 8,000 W-36,000 W, typically 18,000 W) used 1 hours a day costs roughly $102 per month and $1,219 per year. Your cost depends on your exact wattage, usage and local rate. Use the calculator for an exact figure.
How many watts does a electric tankless water heater use?
Whole-home electric tankless units draw a very high 8–36 kW, but only while hot water is flowing.
How much electricity does a electric tankless water heater use per year?
About 6,570 kWh per year at typical usage. That's 18.00 kWh per day at 1 hours of use.
How can I cut the running cost of a electric tankless water heater?
Tankless avoids standby losses, but the huge instantaneous draw needs a heavy dedicated circuit.
Keep exploring
Sources & accuracy
Wattage: U.S. DOE — Estimating Appliance and Home Electronic Energy Use and ENERGY STAR-grade references (typical figures; ranges shown where relevant). Electricity rate: EIA Electric Power Monthly (March 2026). All public domain. Costs are a transparent calculation (see methodology) and are estimates only — your appliance's actual wattage, your usage and your utility rate may differ. Check the appliance label and your bill before relying on these figures.
Last updated: 2026-06-20