Solar panels
Payback from your roof size, region and orientation, using PVGIS data, with self-use and export.
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Free tools
Home energy calculators
Thinking about solar panels, a heat pump, a home battery, a small wind turbine or an EV tariff? Start with a calculator to see if it pays for your home, then read the guide. Every default shows where it came from and when we checked it. No sign-up, and nothing you type leaves your browser.
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Heat pump vs boiler
Running costs against gas or oil, the £7,500 Boiler Upgrade Scheme grant and payback.
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Home battery
Savings from cheap overnight charging and stored solar, against the battery's cost and life.
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Small wind turbine
Home and farm turbines: generation from your wind speed and hub height, with Guernsey Met Office data.
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EV tariff vs price cap
Whether a time-of-use EV tariff beats the standard cap for your home and car.
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Home energy guides
Solar panels
Heat pumps
- Heat pump vs boiler running costs
- The Boiler Upgrade Scheme: who gets the £7,500 heat pump grant
- Electricity tariffs for heat pumps: how time-of-use cuts running costs
- Air source vs ground source heat pumps: which suits your home?
- Do you need planning permission for a heat pump?
- Heat pump sizing, flow temperatures and radiators
Home batteries
Small wind turbines
Energy tariffs
Estimates, not financial advice. Results depend on your home, your tariff and quotes from installers. Prices, grants and tariffs change; each page shows the date its figures were checked.