Water Heating · Northeast
Cost to run a electric water heater in Maine
At Maine’s average residential rate of 28.63¢ per kWh, a electric water heater drawing 4000W for 3 hours a day costs about $47.06 a month. Change the numbers below to match how you actually use yours.
Quick answer
Based on 4000W at a 45% duty cycle (this equipment cycles on and off rather than drawing full power continuously) and 28.63¢/kWh, the Maine average for May 2026.
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— per year
Why the cost differs in Maine
Maine has the 46th cheapest residential electricity of the 51 US states and territories we track, at 28.63¢ per kWh against a national average of 18.44¢. That is +55.3% compared with the national figure. Maine combines high winter heating demand with constrained regional transmission, a costly pairing. Retail supplier choice is available, so contracted rates vary. Heat pump adoption here is among the highest in the country, which is shifting the winter load profile: households that once burned oil now draw electricity through the coldest months, when New England generation costs peak.
For this appliance specifically, the difference works out to an extra $201 a year over what the same electric water heater would cost at the national average rate. Run the identical appliance in Hawaii and it would cost $1,025 a year; in Idaho it would cost $243. That spread of $782 is entirely down to location.
That is about 19% of a typical Maine household's annual electricity bill from this one appliance, which is enough to be worth optimising.
Because Maine is among the most expensive states for electricity, efficiency upgrades pay back faster here than almost anywhere. A more efficient electric water heater that saves a given number of kilowatt-hours saves noticeably more money in Maine than the same upgrade would in a cheap-power state.
Because Maine has retail supplier choice, the state average blends many different contracted rates. If you have shopped for a plan, your own price per kWh is the number to put in the calculator.
| Location | Rate | Per month | Per year |
|---|---|---|---|
| Maine this page | 28.63¢ | $47.06 | $564 |
| US average | 18.44¢ | $30.31 | $363 |
| Idaho cheapest state | 12.35¢ | $20.30 | $243 |
| Hawaii most expensive | 52.00¢ | $85.48 | $1,025 |
Maine electricity rate trend
Rates in Maine have moved from 28.14¢ to 28.63¢ per kWh over the last twelve months of published data. Nationally, residential rates rose about 6.2% year over year.
2025-06 to 2026-05 · cents per kWh
About running a electric water heater
Typically the second-largest load in a home after heating and cooling. Tank models reheat continuously to counter standby loss; heat pump water heaters cut consumption by roughly two-thirds.
What actually changes the cost
- Nameplate wattage is not running cost. This electric water heater draws about 4000W when active, but cycles roughly 45% of the time it is switched on, so effective consumption is near 1800W.
- At typical use this is a major load - around 1,971 kWh a year. Efficiency upgrades here pay back faster than on any small appliance.
- If your utility offers time-of-use pricing, shifting this load off-peak can cut its cost substantially without using any less energy.
How we worked this out
The arithmetic is simple and we would rather show it than hide it. Divide watts by 1,000 to get kilowatts, multiply by hours of use and by the duty cycle to get kilowatt-hours, then multiply by your rate:
4000W ÷ 1000 × 3h × 45% = 5.400 kWh/day × 28.63¢ = $1.546 per day
One honest caveat: Maine’s figure is a state average published by the EIA. Your own utility’s tariff, any time-of-use pricing, fixed monthly service charges and local taxes all shift the real number. Put your actual per-kWh rate into the calculator above for a figure that reflects your bill.
Questions about electric water heater running costs
How many watts does a electric water heater use?
A typical electric water heater draws about 4000 watts while running, with most models falling between 3000W and 5500W. Check the nameplate label or manual for your specific unit - the range is wide enough that averages can mislead.
How much electricity does a electric water heater use per day?
At around 3 hours of use a day and a 45% duty cycle, that works out to roughly 5.4 kWh per day, or about 162 kWh a month. Your actual figure depends on your usage and model.
Why does the cost differ so much between states?
Residential electricity rates across the US range from about 12.35 cents per kWh in North Dakota to 46.62 cents in Hawaii - nearly a fourfold difference. The same electric water heater, used identically, therefore costs almost four times as much to run in the most expensive state as in the cheapest.
Is it cheaper to run a electric water heater at night?
Only if you are on a time-of-use or variable tariff. On a flat rate, the time of day makes no difference to cost. If you are on time-of-use pricing, off-peak hours are typically materially cheaper, and shifting this load can reduce its cost without reducing usage.