Temperature rise is the difference between the incoming groundwater temperature and your desired output (usually 120°F).
Incoming water may be 70°F+, meaning the unit works less to reach 120°F. tankless water heater buying guide lowes
A unit rated for 7 GPM in Florida might only deliver 3 GPM in Maine because it must heat the water more intensely. 3. Choose a Power Source Temperature rise is the difference between the incoming
Unlike tank models measured in gallons, tankless units are sized by , measured in gallons per minute (GPM). To find your size, add up the GPM of every fixture you plan to use at the same time . Typical Fixture Average Flow Rate (GPM) Kitchen Faucet 1.0 – 2.0 GPM Showerhead 2.0 – 3.0 GPM Dishwasher 1.0 – 2.0 GPM Washing Machine 1.5 – 2.5 GPM Source: Lowe's Buying Guide 2. Calculate Temperature Rise Typical Fixture Average Flow Rate (GPM) Kitchen Faucet 1
Incoming water can be as low as 37°F, requiring a high temperature rise (approx. 83°F).