Aquarium heater vs. reptile heat lamp: running cost
An aquarium heater is cheaper to run: about $47 a year versus $79 for a reptile heat lamp at typical use and 17.99¢/kWh, a $32 difference.
| Aquarium heater | Reptile heat lamp | |
|---|---|---|
| Typical watts | 100 W | 100 W |
| Watt range | 25–500 W | 40–250 W |
| Typical use | 24 hours a day | 12 hours a day |
| Energy per year | 263 kWh | 438 kWh |
| Cost per hour | 0.5¢ | 1.8¢ |
| Cost per day | 13¢ | 22¢ |
| Cost per month | $3.94 | $6.57 |
| Cost per year | $47 | $79 |
| Per year in Hawaii (43.51¢) | $114 | $191 |
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What drives the difference
- Aquarium heater: Heaters cycle with the thermostat; in a 70°F home a heater runs about 25-40% of the time.
- Reptile heat lamp: Basking bulbs draw their rated watts the whole time they're on; a 100 W lamp 12 hours a day uses about 440 kWh a year.
Ways to cut either cost
Aquarium background insulation
Cuts heat loss through the glass.
See options on Amazon Reptile thermostat
Dims the lamp when the basking spot is warm enough.
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Frequently asked questions
Which costs more to run, an aquarium heater or a reptile heat lamp?
At typical use and the U.S. average rate (17.99¢/kWh), a reptile heat lamp costs about $79 a year versus $47 for an aquarium heater. That's $32 more, or 1.7× as much.
How many watts do aquarium heater and reptile heat lamp use?
An aquarium heater typically draws 100 W (range 25–500 W). A reptile heat lamp draws 100 W (range 40–250 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.