Calculators

Work out what size tank or tankless water heater your home needs from your busiest hour of hot water use.

Estimate what replacing your water heater will cost in 2026: tank, tankless or heat pump, your area, and the extras your installation may need.

Enter the age of your water heater and the repair quote to see whether repairing or replacing makes more sense, and why.

Work out the flow rate, gas BTU or electric kW your tankless water heater needs, based on fixtures, climate and hot water temperature.