Solar yield
A year’s AC energy from array size, a typical regional yield and one or two roof planes.
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Energy and home
Solar, a heat pump, a power bill, insulation, hot water and an EV kilometre.
Solar sizing
How large a photovoltaic array would cover a chosen share of yearly electricity use.
Open a calculatorSolar payback
A simple payback period from net install cost, self-consumption and the buy and sell prices.
Open a calculatorPV kit
A bill of materials from real modules, mounts, cable, inverters and batteries, with a street-price sketch.
Open a calculatorHeat pump
A year’s space-heat demand from floor area and a rough insulation class, then electricity at a chosen SCOP versus gas.
Open a calculatorCooling load
A first-pass air-con size from floor area and watts per square metre.
Open a calculatorHeating fuel comparison
The same yearly heat in gas, pellet, coal, wood, oil, resistance heat and a heat pump.
Open a calculatorDomestic hot water
Heat and electricity to raise daily litres by a temperature difference, then a running cost.
Open a calculatorHeat loss through a surface
Kilowatt-hours through a wall, window or roof from U, area and ΔT.
Open a calculatorGas bill
A month of gas from cubic metres, a kWh factor, energy price and a fixed fee.
Open a calculatorAppliance cost
Kilowatt-hours and the bill for a device from watts and hours a day.
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A period bill from cubic metres and the water and sewage prices.
Open a calculatorEV running cost
Cost per 100 km and per year for an electric car charged at home and at a public post, against a petrol car.
Open a calculatorEV charge time
Hours to move the battery between two states of charge.
Open a calculatorEV range
Kilometres from usable battery and kWh per 100 km, plus a colder-weather hit.
Open a calculatorStandby draw
A year of a device that never quite switches off.
Open a calculatorLED swap
Kilowatt-hours and money saved by swapping a bulb.
Open a calculatorHeating degree days
Season heat from heating degree days and a UA value.
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