The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) announced on July 2 a decision to delist mix-match coil-blower combinations, effective July 15, that exceed 6 percent of a system manufacturers’ highest sales volume tested (HSVT) combinations. In a quick reaction to comply, some OEMs and third-party independent coil manufacturers (ICMs) announced that they would immediately begin to review and possibly revise their ratings, perhaps prior to the July 15 deadline.

The events have left many distributors and contractors wondering about inventory issues and how to support system ratings that may have previously been quoted to customers.

The products subject to the delisting are overseen by the organization’s Unitary Small Equipment (USE) section. Delisting from the AHRI Directory of Certified Product Performance does not mean that affected products cannot continue to be sold in the marketplace, only that the performance cannot be certified by AHRI.

According to the Air Conditioning Contractors of America (ACCA), this poses a few different problems. In a letter to AHRI dated July 7, Paul Stalknecht, ACCA president and CEO, said, “We applaud AHRI in this action in that there has been a perceived problem in this portion of the unitary certification program for many years. However, ACCA has grave concerns with the timing and implementation strategy. We believe that the proposed AHRI action and timeline will lead to immediate difficulties in the field.”

One concern voiced by ACCA was that contractors have been submitting long-lead proposals based upon the current AHRI database of certified matches. In many cases, these matched systems were selected in order to provide utility rebates or federal tax credits. Many contractors expect to provide their customers with AHRI Certificates of Performance for use as validation of an energy efficiency home improvement that qualifies for a tax credit.

In addition, many contractors and distributors have purchased inventory that relied upon third-party coil-only manufacturers to obtain a matched system. With normal lead times of four to eight weeks, there is not time to restock for the season. Decertifying coil combinations could lead to order fulfillment problems.


The perceived problem referred to in the ACCA letter refers to the opportunity to match equipment system manufacturer’s condensing units with independent coil manufacturers’ (ICMs) evaporator coils to gain higher efficiencies. There has been an ongoing controversy about the actual performance of ICM coils. These coils have the advantage of being rated differently (computer simulations), and many have argued that the ICM ratings lead to a 1 to 1.5 SEER point advantage for products that are nominally the same size. There were changes to the test requirements a few years ago to help limit these differences; however, another complicating issue is the fact that ICM computer simulations are not standardized and are not required to use the same Department of Energy (DOE) data that are used in OEM system testing.


The tax credit program may have been the impetus behind the AHRI action. Initially, very few large units (4 ton and above) met the 16 SEER/13 EER requirement for a/c units. Now, there are approximately 30,000 system matches that will qualify within the federal tax credit program. It is faster to qualify a unit with computer simulations than to run a real unit through the entire certification process, and it is possible that the DOE raised an eyebrow at the sudden rush of qualifying matches, thereby causing the AHRI action.

According to an AHRI FAQ document that accompanied the announcement, “The dramatic increase in the number of mix-match coil combinations entered into our directory by manufacturers has overwhelmed our ability to conduct our normal testing procedures to assure the manufacturers’ stated performance. The Department of Energy requires special scrutiny of combinations having coil-only ratings that are more than 6 percent above the system manufacturers’ ratings. AHRI has decided to delist products that exceed that threshold until a process has been established that provides the additional testing required to verify the performance levels.”

Publication date:07/20/2009