System Performance

Equipment is built and rated by the OEM (Original Equipment Manufacturer). It is normally packaged for sale and ultimately delivered to an installing contractor. Remember, each piece of equipment is a stand-alone product. The installing contractor selects and fabricates many parts and pieces to assemble the selected components and build a new and different product, an HVAC system. For many decades, the published equipment efficiency rating number has been mistakenly interpreted to represent the installed system efficiency rating. Equipment and an installed system are two separate products and should be rated or scored separately.

An installed system’s score expresses the percent of the equipment rated capacity delivered into the building by the installed system delivered capacity. Field testing pinpoints defects that deteriorate system and equipment performance. Then each flaw can be corrected allowing the equipment to operate within published specifications.

For decades, the National Comfort Institute (NCI) mission has been to enable HVAC professionals to test, diagnose, and resolve undetected system defects. Thanks to a dedicated committee and standards organization, the industry now has a standard that improves and legitimizes the way to test and score HVAC system performance.