DoesTheMath

Gas tankless water heaters on file

Gas-fired instantaneous units, sized by flow rate rather than tank gallons.

489 registered models are gas tankless water heaters. Their filed UEF runs from 0.81 to 0.98 across 4 draw patterns. Each is listed below with its yearly energy, and compared only with others of the same draw pattern.


Other collections


Very small draw pattern

small units - a single bathroom, or a point-of-use heater under a sink — 2 models, lowest yearly energy first.


Low draw pattern

a one- or two-person household — 10 models, lowest yearly energy first.


Medium draw pattern

a typical three- or four-person household, about 55 gallons on a busy morning — 80 models, lowest yearly energy first.


High draw pattern

a larger household, or one where showers and laundry overlap — 397 models, lowest yearly energy first.

DOE CCD · 2026-09-19