Indirect Water Heaters (IWH)
Related Standard(s) and Documents
This program applies to Indirect Water Heaters having a volume (potable plus heat source) of 120 gallons or less, for which Published Ratings are available, and which are designed for installation with a hot water boiler(s) as the only heat source.
- Direct-fired instantaneous or storage water heaters;
- Tankless water heaters;
- Heat pumps water heaters, and;
- Combination space heating and water heating appliances
Voluntary Program Scope Inclusion
Indirect Water Heaters for use with alternate heat sources meeting the scope of the Applicable Rating Standard may be included in the Program, provided that general advertising and promotional literature will not claim certification unless all models are certified or unless certification is clearly claimed only for certified models. Models listed with AHRI under the IWH certification program must always be sold as certified when they meet the scope of the certification program. These models can be found on the AHRI Directory of Certified Product Ratings.
The following certification program ratings are verified by test:
- Standby Loss, °F/hr
- First Draw Rating, gal/hr
- Continuous Draw Rating, gal/hr
- Heat Source Friction Loss, ft w.c.