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How Much Does It Cost to Run a Aquarium (Heater, Filter, Light) in the UK? (2026)

An aquarium's cost is mostly the heater, which cycles on and off to hold temperature, plus a filter pump running all day and lights on for 8 to 12 hours. A 100 litre tropical tank uses roughly 30 to 60 kWh a month.

A typical aquarium (heater, filter, light) (80 W) costs £0.021 per hour, or about £7.49 per month at 12 hours a day in United Kingdom. Average running cost

WattagePer hourPer dayPer monthPer year
Low (30 W)£0.008£0.094£2.81£34.16
Typical (80 W)£0.021£0.25£7.49£91.10
High (300 W)£0.078£0.94£28.08£341.64

Formula: watts ÷ 1000 × hours × price per kWh. Typical use is 12 h/day ≈ 350 kWh per year.

In the UK, with electricity at £0.26 per kWh (source: Ofgem price cap 1 Jul–30 Sep 2026, 2026-07), a typical aquarium (heater, filter, light) costs £0.021 per hour and about £91.10 per year at 12 hours a day. Each £1.00 of electricity buys roughly 48.1 hours of use.

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How to lower the cost of running a aquarium (heater, filter, light)

Frequently asked questions

How much does an aquarium cost to run per month?

A typical 100 litre heated tank uses 30 to 60 kWh a month. Pick your region above.

Which part of an aquarium uses the most electricity?

The heater in a cool room. In a warm room, the lights.

Does a bigger tank cost proportionally more?

Less than proportionally. Larger tanks hold temperature better per litre.

Cost by region

Related appliances

Use the generic electricity cost calculator →