Condensing tankless water heater prices
Condensing heaters recover heat from their own exhaust: UEF of about 0.93 to 0.97, and they vent through ordinary PVC instead of stainless steel. 48 models from 5 stores, with prices checked daily.
Check the size your household needs and what it costs to run.
Best value ($/GPM)
$120
Takagi T-H3S-OS-P Condensing Outdoor Tankless Water Heater, Propane · PEX Universe
Cheapest heater
$560
ThermoMate CZ480LP Indoor Tankless Water Heater, 5.28 GPM, Propane · ThermoMate (official store)
Typical $/GPM
$184
Median across 36 in-stock listings
All stores
All brands
$/GPM is the price divided by the hot water flow the heater delivers at a 45 °F temperature rise, worked out from its gas input and UEF. "Box GPM" is the maker's own maximum, often quoted at a much smaller rise, so it is shown but not ranked on. Your rise depends on your incoming water: the sizing calculator works it out from your ZIP.