ARLINGTON, Va. — An internal review by the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) revealed an aspect of the current U.S. Department of Energy (DOE) efficiency test procedure for residential furnaces and boilers that may result in an inaccurate AFUE measurement for two-stage or modulating condensing residential boilers. The problem in the test procedure is in the calculations used to determine the AFUE when selecting the option of skipping the heat-up and cool-down tests.
These ratings were based on the current DOE efficiency test procedure, and the error is due to an inconsistency in those procedures rather than a failure to properly conduct the DOE test. All the involved models are highly efficient and exceed the current federal minimum AFUE for these products, so there is no issue with their compliance with federal minimum-efficiency standards.