Tankless Water Heater Calculator

Size your tankless water heater based on your home's hot water needs

Location & Temperature

Average groundwater temperature for your area
Standard is 120°F (safe for most uses)

Temperature Guide:

  • 120°F: Safe temperature for most homes (prevents scalding)
  • 125°F: Recommended for dishwashers without built-in heaters
  • 130-140°F: Commercial use or homes with compromised immune systems

Select Your Fixtures

Choose the fixtures you'll use simultaneously (at the same time):

Shower 2.5 GPM
0
Bathtub 4.0 GPM
0
Kitchen Sink 1.5 GPM
0
Bathroom Sink 1.0 GPM
0
Dishwasher 1.5 GPM
0
Washing Machine 2.0 GPM
0

Typical Usage Scenarios:

  • Small Home (1-2 people): 1 shower + 1 kitchen sink = 4.0 GPM
  • Medium Home (2-3 people): 1 shower + 1 kitchen sink + 1 bathroom sink = 5.0 GPM
  • Large Home (4+ people): 2 showers + 1 kitchen sink = 6.5 GPM