Tools hub
Free Energy Calculators & Tools
Explore practical calculators organised by topic. Each tool is designed to help you compare options, estimate savings, and make better-informed energy decisions with UK-focused assumptions.
Heating
Browse heating tools
Electric Heater Running Cost Calculator
Estimate running costs for direct electric heating.
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Heat Pump Suitability Checker
Score how ready your home is for a heat pump and spot likely upgrade needs.
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Boiler vs Heat Pump Running Cost Calculator
Compare annual heating costs, carbon, and 10-year spend.
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Radiator Size for Low-Temp Heating
Check whether existing radiators are large enough for heat-pump flow temperatures.
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Heating System Sizing Estimator
Estimate peak heat loss and a sensible starting-point system size range.
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Energy Cost
Browse energy cost tools
Renewables
Browse renewables tools
Solar PV Savings Calculator
Estimate solar generation, savings, and export income.
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Battery Storage Payback Calculator
Compare self-consumption gains from home storage.
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EV Solar Charging Planner
Estimate how much solar can support EV charging.
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Grants