If you’re thinking of buying a new tankless water heater, you’ll want to know how much hot water your family uses. Here’s a simple chart to give you an idea of how much hot water your household uses.
For the chart below, GPM (gallons per minute) measures the steady flow of hot water that each fixture will require.
For example, If you run a bathroom faucet with a flow rate of 1.0 GPM and shower head with a flow rate of 1.5 GPM at the same time, the total flow rate through the water heater needs to be at least 2.5 GPM.
To determine the capacity of the tankless water heater you will need, add up the GPM for the major fixtures and appliances that you expect to use at the same time.
Gallons Per Minute / Flow Rate
|Fixture / Appliance||Typical Flow Rates|
|Bathroom Faucet||0.5 – 1.5 GPM|
|Low Flow Kitchen Faucet||
1.0 – 2.5 GPM
1.0 – 2.0 GPM
|Dishwasher||1.0 – 2.5 GPM|
|Clothes Washer||1.5 – 3.0 GPM|