Electric Water Heater Cost Per Month Calculator
Enter how much hot water your household uses, how much the heater warms it and the heater's UEF, and get the cost per day, month and year in your state.
Electric water heater cost
A06Scenario A
Sets the electricity rate. Pick US average if you're not sure.
From EIA for US average. Use the rate on your bill if you know it.
Rate used: 18.4¢/kWh · US average · EIA reference 2025–26 (data as of 2026-09-26) ·
DOE estimates about 16 gallons per person per day. 64 gallons ≈ a family of 4.
Tank setting minus the temperature of the incoming water. Colder in the North and in winter.
Uniform Energy Factor on the EnergyGuide label. Standard electric tanks are about 0.9; heat pump models are much higher. The calculator accepts up to 4.0.
Estimated cost per month
Estimate. Formula and sources are under “How it works”. Change any input; the result updates as you type.
2026 note: The federal 25C and 25D tax credits ended for installations after Dec 31, 2025. Our numbers use 2026 rules. State rebates, HEAR/HOMES programs and utility programs may still apply.
Formula
How it works
- kWh per day = gallons per day × 8.34 × temperature rise (°F) ÷ 3,412 ÷ UEF
- Cost per month = kWh per day × 30 × rate
Water weighs 8.34 lb per gallon, and it takes 1 BTU to warm 1 lb by 1 °F. 3,412 BTU = 1 kWh. The UEF covers everything the heater loses along the way, including standby heat loss from the tank. For a family of four (64 gallons a day, 70 °F rise, UEF 0.92) that's about 11.9 kWh a day, the same as running a 4,500 W element for 2.6 hours. After heating and cooling, water heating is the biggest energy use in most homes.
Sources: 8.34 lb/gal and 1 BTU/lb·°F (physical constants); UEF per DOE test procedure, 10 CFR 430; 16 gal/person/day (DOE). Electricity rate: EIA Electric Power Monthly table 5.6.A.
Worked example
A worked example
A household using 48 gallons of hot water a day, heated 60 °F with a UEF 0.92 tank, needs 48 × 8.34 × 60 ÷ 3,412 ÷ 0.92 = 7.65 kWh a day. At the Texas rate of 15.5¢/kWh that's $1.19 a day, $35.58 a month and $432.90 a year.
Reference
Reference table
Electric water heater cost per month at 18.4¢/kWh (US average), 70 °F rise
| UEF 0.92 · standard tank | UEF 3.0 · heat pump | |
|---|---|---|
| 1 person | $16.43 | $5.04 |
| 2 people | $32.85 | $10.07 |
| 3 people | $49.28 | $15.11 |
| 4 people | $65.70 | $20.15 |
| 5 people | $82.13 | $25.19 |
Questions
FAQ
How much does a 50-gallon electric water heater cost per month?
Tank size matters less than how much hot water you use. At the US average rate of 18.4¢/kWh, a family using 64 gallons a day with a 70 °F rise and a UEF 0.92 tank pays an estimated $65.70 a month. In California at 32.0¢/kWh, 80 gallons a day (UEF 0.95) comes to $138.32.
Why is my water heater cost higher in winter?
The incoming water is colder, so the temperature rise is bigger. Raise the temperature rise input and the kWh go up in proportion.
Is a tankless water heater cheaper to run?
A tankless heater has no standby loss from a tank, which shows up as a higher UEF. Enter its UEF from the EnergyGuide label to compare. A full tankless vs tank calculator is on our roadmap.
How much would a heat pump water heater cost to run?
Heat pump water heaters have a much higher UEF than standard tanks. For example, the same family of four at UEF 3.0 would use about 3.65 kWh a day instead of 11.90, roughly a third of the cost. Enter the model's UEF to see it at your rate.
Does lowering the thermostat save money?
Yes, in proportion to the temperature rise. Going from a 70 °F rise to a 60 °F rise cuts the energy by one-seventh. Keep the tank hot enough for safe use; check the manufacturer's guidance.
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