Method of Testing for Rating Residential Water Heaters
ASHRAE Standard Project Committee 118.2

Committee Title, Purpose and Scope

• TITLE: Method of Testing for Rating Residential Water Heaters
• PURPOSE: The purpose of this standard is to provide test procedures for rating the efficiency and hot water delivery capabilities od directly heated residential water heaters.
• SCOPE: This standard applies to the following:
  a. gas-fired water heaters with a self-contained, temperature-activated primary operating control and not requiring circulation of water for heating (Type I), with rated input no greater than 75,000 Btu/h (22 kW);
  b. oil-fired water heaters with a self-contained, temperature-activated primary operating control and not requiring cir culation of water for heating (Type I), with rated input no greater than 105,000 Btu/h (30.8 kW);
  c. electric resistance water heaters with a primary self-contained, temperature-activated operating control and not requiring circulation of water for heating (Type I), with rated input no greater than 12 kW;
  d. gas-fired water heaters with a self-contained, flow-activated primary operating control and requiring water flow for heating (Type II), with rated input no greater than 200,000Btu/h (61.5 kW)
  e. oil-fired water heaters with a self-contained, flow-activated primary operating control and requiring water flow for heating (Type II), with rated input no greater than 210,000 Btu/h (61.5 kW);
  f. electric resistance water heaters with a self-contained, flow-activated primary control and requiring water flow for heating (Type II), with rated input no greater than 12 kW;
  g. gas-fired water heaters with a remote temperature-activated primary operating control and requiring circulation through the heater for heating (Type III), with rated input no greater than 75,000 Btu/h (22 kW),
  h. oil-fired water heaters with a remote temperature-activated primary operating control and requiring circulation of water through the heater for heating (Type III), with rated input no greater than 105,000 Btu/h (30.7 kW);
  i. electric resistance water heaters with a remote temperature-activated operating control and requiring circulation through the heater for heating (Type III), with rated input no greater than 12 kW; and
  j. single-phase air-source heat-pump water heaters (Types IV and V), with rated input no greater than 6 kW.