Heating · Hawaii
How Much Does It Cost to Run an Electric Water Heater in Hawaii?
The short answer
Running a 4,500W electric water heater in Hawaii costs about $2.16 an hour. At 3 hours a day, that’s roughly $197 a month and $2,365 a year.
That’s based on Hawaii’s average residential rate of 48.0¢/kWh (EIA, July 2026), 162% above the US average.
Source: U.S. EIA, July 2026 data · Updated
Electric Water Heater cost by daily use in Hawaii
| Daily use | kWh/month | Per day | Per month | Per year |
|---|---|---|---|---|
| 1 hour/day | 136.9 | $2.16 | $65.71 | $788 |
| 2 hours/day | 273.8 | $4.32 | $131 | $1,577 |
| 4 hours/day | 547.6 | $8.64 | $263 | $3,154 |
| 8 hours/day | 1,095.1 | $17.28 | $526 | $6,307 |
| 12 hours/day | 1,642.7 | $25.92 | $788 | $9,461 |
| 24 hours/day | 3,285.4 | $51.84 | $1,577 | $18,922 |
Hawaii vs other states
Hawaii has the most expensive electricity in the country, so running an electric water heater here costs $1,738 more a year than in Louisiana at the same usage.
Hawaii has the most expensive residential electricity of the 50 states and DC. Hawaii price per kWh · all states ranked
Electricity price trend in Hawaii
48.0¢/kWh in July 2026 — ▲ +22.0% from a year earlier.
How to lower the cost of running an electric water heater
Electric tank water heaters keep 40–80 gallons of water hot around the clock, switching their heating elements on whenever you use hot water or the tank cools down. The elements are typically 4,500W, and total run time for a family is roughly 2–4 hours a day, which is why water heating is often the second-biggest line on an all-electric home's bill. Heat pump water heaters do the same job with 2–3 times less electricity.
- Set the tank to 120°F (49°C) — many ship at 140°F, which wastes energy.
- Insulate the first few feet of hot water pipe and fix dripping hot taps.
- Consider a heat pump water heater when your tank needs replacing — they use about a third of the electricity.
Questions
Frequently asked questions
How much does it cost to run an electric water heater for 24 hours in Hawaii?
Running a 4,500W electric water heater for 24 hours uses about 108 kWh, which costs about $51.84 at Hawaii’s average rate of 48.0¢/kWh.
How many kWh does an electric water heater use per month?
At 3 hours a day, a typical electric water heater uses about 411 kWh a month. In Hawaii that costs $197.
Is it expensive to run an electric water heater in Hawaii?
Hawaii has the most expensive residential electricity of the 50 states and DC at 48.0¢/kWh — one of the most expensive. Running an electric water heater here costs about $2,365 a year at typical use, compared with $902 at the national average rate.
What is the electricity rate in Hawaii right now?
The average residential electricity rate in Hawaii was 48.0¢ per kWh in July 2026, according to the latest EIA data — up 22.0% from a year earlier.
How many hours a day does an electric water heater run?
For a typical household, about 2–4 hours a day in total, spread across showers, laundry and dishes, plus short reheats to make up for standby heat loss.
Electric Water Heater costs in nearby states
Other appliances in Hawaii
Cheapest and priciest states
Sources & method
- Electricity rates: U.S. Energy Information Administration, Electric Power Monthly — average residential retail price, July 2026 (latest available). Retrieved .
- CO₂: EIA State Electricity Profiles, 2024 emissions rate of in-state power generation.
- Default usage for electric water heater: 3 hours a day. Typical power 4,500W.
- Formulas, duty cycles and limitations: methodology. Data download: open data (CC BY 4.0).