Commercial central air conditioners (CACs) and heat pumps (HPs) (<65,000 Btu/hr) are nearly identical to typical residential CACs and HPs, but are designed to operate on 3-phase electric power rather than single-phase power. Power supplied to residential buildings is almost always single-phase, while most commercial buildings are wired with 3-phase power. Commercial 3-phase CACs and HPs can be either "single package" systems, where the evaporator coil and the condensing unit are combined into a single physical unit, or "split systems," where the condensing unit is typically placed outdoors while the evaporator is indoors.
In 2015, DOE adopted the efficiency levels for commercial 3-phase CACs and HPs in the 2013 version of ASHRAE 90.1 as new national minimum standards. ASHRAE 90.1 is a commercial building energy code. The Energy Policy and Conservation Act (EPCA) requires that if the equipment efficiency levels in ASHRAE 90.1 are amended, DOE must either establish amended standards for the products at the levels specified in ASHRAE 90.1 or establish more stringent standards if they would result in significant additional energy savings and are technologically feasible and economically justified.
The new standards took effect in January 2017. The standards are generally equivalent to those for residential CACs and HPs except that the standards for commercial CACs do not include a regional component like those for residential CACs. For split-system commercial 3-phase CACs, the minimum cooling efficiency remained unchanged at Seasonal Energy Efficiency Ratio (SEER) 13. (For residential split-system CACs, the minimum standard is SEER 13 in the North and SEER 14 in the South.) For single-package air conditioners and all heat pumps, the minimum cooling efficiency is SEER 14, which is equivalent to the standard for residential units. The heating efficiency standards for commercial 3-phase HPs are Heating Seasonal Performance Factor (HSPF) 8.2 and 8.0 for split-system and single-package units, respectively, which are also equivalent to the standards for residential HPs.
CACs and HPs are rated by their cooling capacity (in Btu/hr), which represents the amount of heat that an air conditioner or heat pump can remove from an enclosed space per hour. One “ton” of cooling capacity is equal to 12,000 Btu/hr. Compared to older units, products meeting the latest standards generally incorporate improved compressors and expansion valves and better and larger heat exchangers.