Tankless Size Chart

Flow rate and temperature rise of small tankless water heaters for ADUs, cabins and off-grid buildings

Section 13

Tankless water heater sizing examples

These four examples size a heater for an ADU, a cabin, a garden office and an outdoor shower. Each one lists the fixtures, the rise and the models that deliver the flow or fall short.

  1. Sizing example: one-bath electric ADU in Wisconsin
    A one-bath electric ADU in Wisconsin, 3.0 GPM at a 68 F rise.
  2. Sizing example: two-shower propane cabin in Colorado at 8,500 ft
    A two-shower propane cabin in Colorado at 8,500 ft, 4.0 GPM at a 63 F rise.
  3. Sizing example: kitchen sink in a Georgia garden office
    One 1.5 GPM kitchen sink in a Georgia garden office, a 48 F rise.
  4. Sizing example: off-grid outdoor shower on an Eccotemp portable heater
    An off-grid outdoor shower on an Eccotemp portable heater with 52 F well water.