Aquarium vs. aquarium heater: running cost
An aquarium heater is cheaper to run: about $47 a year versus $77 for an aquarium at typical use and 17.99¢/kWh, a $29 difference.
| Aquarium | Aquarium heater | |
|---|---|---|
| Typical watts | 135 W | 100 W |
| Watt range | 30–1,000 W | 25–500 W |
| Typical use | 24 hours a day | 24 hours a day |
| Energy per year | 426 kWh | 263 kWh |
| Cost per hour | 0.9¢ | 0.5¢ |
| Cost per day | 21¢ | 13¢ |
| Cost per month | $6.39 | $3.94 |
| Cost per year | $77 | $47 |
| Per year in Hawaii (43.51¢) | $185 | $114 |
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What drives the difference
- Aquarium: Watts are total heater, filter and light ratings. The heater cycles and the light runs about 8 hours, so a heated 29-gallon tank averages about 50 W, roughly 400 kWh a year. Reef tanks with pumps and lighting use far more.
- Aquarium heater: Heaters cycle with the thermostat; in a 70°F home a heater runs about 25-40% of the time.
Ways to cut either cost
Aquarium background insulation
Cuts heat loss through the glass.
See options on Amazon LED aquarium light
Uses about half the power of fluorescent fixtures.
See options on AmazonWe may earn a commission from qualifying purchases. It never changes the numbers we show. Disclosure.
Frequently asked questions
Which costs more to run, an aquarium or an aquarium heater?
At typical use and the U.S. average rate (17.99¢/kWh), an aquarium costs about $77 a year versus $47 for an aquarium heater. That's $29 more, or 1.6× as much.
How many watts do aquarium and aquarium heater use?
An aquarium typically draws 135 W (range 30–1,000 W). An aquarium heater draws 100 W (range 25–500 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.