Home Energy Calculators

Estimate a monthly electricity bill from kWh with block-tier rates, a fixed monthly charge and a tax or fee percentage.

Electric vehicle charging time, cost and range added from battery size, charge levels, charger power or circuit, and price.

Heat loss of a building in BTU/h and watts from surface areas and R-values plus air leakage, and yearly energy from degree-days.

Cost per million BTU of delivered heat for resistance, heat pump, gas, propane and heating oil furnaces, from your prices.

Total a list of appliances (watts, hours a day, quantity) into kWh and cost per day, month and year, with each one's share.

Room air-conditioner BTU from floor area (ENERGY STAR chart), tons, and an under- or over-sizing check against a load.

R-value and U-factor of a wall or roof assembly from layers and thickness, with a framing-fraction correction and heat flow.

Size a rooftop solar system from annual kWh and peak sun hours: kW, panel count, yearly output, savings and simple payback.

Water heater recovery rate (gallons an hour), tank heat-up time and energy cost from input power, efficiency and rise.