Free UK home energy tools

Electricity maths, without the headache.

Use a calculator immediately. Every answer includes a simple explanation, the formula and the assumptions behind the estimate.

Appliance electricity cost

Turn watts, hours and your electricity price into daily, monthly and yearly estimates.

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W, kWh, Ah and volts

Understand the confusing units with simple examples, then make an honest conversion.

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400W or 800W solar?

Use estimated daytime electricity consumption to find which size may be worth exploring.

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Standby electricity cost

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Home energy check-up

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Results are estimates for learning and comparison. They do not confirm product suitability, installation requirements, electricity generation, bill savings or payback.