What does an aquarium cost to run?

Run the numbers on your own use

Change any of these and the figures update. The defaults are the typical case described above; your rate is the input that moves the answer most.

Why this is lower than the number you will see elsewhere

Almost every published answer to this question multiplies the rating on the label by the hours the appliance is switched on. For an aquarium that gives 1,314 kWh a year, or $241.

Heater and lights dominate; the filter is small and continuous. The heater cycles on room temperature.

The arithmetic, step by step

Nothing here is hidden, so you can check it or change it. Working in the order the formula runs:

1. 150 W — what it draws while it is actually drawing. This is the rating on the plate.
2. × 35% — the share of its in-service time it is really pulling that. Heater and lights dominate; the filter is small and continuous. The heater cycles on room temperature.
   That gives 53 W averaged across the hours it is on.
3. × 24 hours a day × 365 days — A 55-gallon tropical tank with heater, filter and LED lighting.
   53 × 24 × 365 ÷ 1,000 = 460 kWh a year.
4. × 18.34¢ — the US average residential rate for June 2026.
   460 kWh × 18.34¢ = $84 a year.

Change any assumption in the calculator above and every figure on this page moves with it. The two that matter most are your rate, which varies 4× across the country, and the hours — the duty cycle is a property of the appliance, but the hours are a property of you.

How sensitive is that number?

A single figure invites more confidence than it deserves. Here is the same appliance under assumptions either side of the default, so you can see how much of the answer is the appliance and how much is the guess about how you use it.

Everything else held at the default. The spread here is the honest error bar on the headline figure.

What it costs per hour, day and month

At 18.34¢ per kWh, the US residential average for June 2026.

The thing worth knowing

The heater’s duty cycle is set by the difference between room temperature and tank temperature, so the same tank costs twice as much in a cold room. A reef tank with metal halide lighting and a chiller is a different animal entirely and can rival a fridge.

What it costs in your state

The appliance is the same everywhere; the rate is not. Running this aquarium costs $242 a year in Hawaii and $60 in Nevada — a difference of 4×.

Cost of running one aquarium for a year, by state. Residential average price, EIA June 2026.

Other water heating and pumps costs

• Hot tub

  $602 a year

  A 400-gallon tub held at 102F year round, well covered.

• Pool heat pump

  $576 a year

  Holding a residential pool at swimming temperature through an extended season.

• Electric water heater

  $499 a year

  A 50-gallon tank serving a household of three to four.

• Pool pump

  $396 a year

  A single-speed pump on an eight-hour timer through the season.

• Koi pond pump

  $241 a year

  A pump circulating a mid-size koi pond through its filter, year round.

• Heat pump water heater

  $177 a year

  A 50-gallon hybrid in a basement, resistance backup rarely engaged.

Questions

Source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, June 2026. U.S. Government work, public domain.

How every figure on this page is computed · Where the data comes from