Point-of-use water heater vs. mini tank water heater: running cost
A point-of-use water heater is cheaper to run: about $57 a year versus $81 for a mini tank water heater at typical use and 17.99¢/kWh, a $23 difference.
| Point-of-use water heater | Mini tank water heater | |
|---|---|---|
| Typical watts | 3,500 W | 1,440 W |
| Watt range | 2,400–13,000 W | 1,000–2,000 W |
| Typical use | 15 minutes a day | 450 kWh a year |
| Energy per year | 320 kWh | 450 kWh |
| Cost per hour | 63¢ | 0.9¢ |
| Cost per day | 16¢ | 22¢ |
| Cost per month | $4.79 | $6.75 |
| Cost per year | $57 | $81 |
| Per year in Hawaii (43.51¢) | $139 | $196 |
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What drives the difference
- Point-of-use water heater: Point-of-use tankless heaters draw 3.5-13 kW for a single sink or shower and only while water flows.
- Mini tank water heater: Mini tanks (2.5-7 gallons) plug into a 120 V outlet and draw about 1,440 W; standby heat loss of about 0.4-0.6 kWh a day is most of their annual use.
Ways to cut either cost
Cuts the flow the heater must warm.
See options on AmazonAvoids keeping water hot 24 hours a day.
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Frequently asked questions
Which costs more to run, a point-of-use water heater or a mini tank water heater?
At typical use and the U.S. average rate (17.99¢/kWh), a mini tank water heater costs about $81 a year versus $57 for a point-of-use water heater. That's $23 more, or 1.4× as much.
How many watts do point-of-use water heater and mini tank water heater use?
A point-of-use water heater typically draws 3,500 W (range 2,400–13,000 W). A mini tank water heater draws 1,440 W (range 1,000–2,000 W). Watts alone don't decide cost. Hours of use, cycling and standby matter just as much.
Rates: EIA, 12 months ending 2026-07. Methodology.