Solar PV yield
Estimate annual AC solar generation from system size, regional irradiation, and one or two roof orientations.
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Energy, solar PV & heating calculators
Solar PV (yield, sizing, payback, kit BOM), heat pump vs gas, G11/G12 electricity bills, heating fuels, U-value heat loss and hot water.
Solar PV sizing
Calculate what solar array size (kWp) and panel count you need to cover a chosen share of your annual electricity consumption.
Open calculatorSolar PV payback
Calculate the simple payback period from net installation cost, self-consumption share, and grid buy/sell rates.
Open calculatorPV kit configurator
Build a PV kit from panels, inverters, batteries, mounting and labour and estimate its cost.
Open calculatorHeat pump vs gas boiler
Estimate annual space-heating demand from floor area and insulation class, then compare heat-pump electricity cost (by SCOP) against a gas boiler.
Open calculatorAir-conditioning cooling load
Estimate required air-conditioner cooling capacity in watts and BTU/h from room floor area and thermal load per m².
Open calculatorHeating fuel comparison
Compare the annual cost of generating the same amount of useful heat across gas, pellets, coal, wood, heating oil, electric resistance and a heat pump.
Open calculatorDomestic hot water
Calculate thermal energy, electricity use and running cost to heat daily hot water by a chosen temperature rise.
Open calculatorHeat loss through a surface (U-value)
Calculate thermal energy lost (kWh) and heating cost through a wall, window or roof from its U-value, area and temperature difference.
Open calculatorGas bill
Convert gas meter readings from cubic metres (m³) into kilowatt-hours (kWh) and calculate your monthly bill including standing charges.
Open calculatorAppliance electricity cost
Calculate electricity consumption (kWh) and running cost for any appliance from its wattage and daily operating hours.
Open calculatorWater and sewage bill
Calculate your water and wastewater bill from meter consumption in cubic metres (m³) and local utility tariffs.
Open calculatorRainwater tank
Work out how many litres of rain your roof collects, which tank size is enough and how much you save on water and sewage.
Open calculatorEV vs petrol running cost
Compare the cost per 100 km and annual energy bill for an electric car (home and public charging) against a petrol car.
Open calculatorEV charging time
Calculate how many hours it takes to charge an electric vehicle between two states of charge (SoC).
Open calculatorEV range (summer & winter)
Estimate real-world electric vehicle range from battery capacity and kWh/100 km consumption in normal and winter conditions.
Open calculatorStandby power cost
Calculate the annual energy use (kWh) and cost of electronics left on standby 24/7.
Open calculatorLED bulb swap savings
Calculate the kilowatt-hours and money saved by replacing old bulbs with LEDs.
Open calculatorHeating degree days (HDD)
Estimate seasonal space-heating energy from heating degree days (HDD) and your building’s heat-loss coefficient (UA).
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