Efficiency
EER2
A cooling-efficiency rating measured at a specified full-load test condition.
What is EER2?
EER2 stands for Energy Efficiency Ratio 2. Under the DOE central air-conditioner and heat-pump test procedure, EER2 represents cooling efficiency from the applicable full-load A test condition. It is expressed in BTU of cooling per watt-hour of electrical input.
EER2 is different from SEER2. SEER2 summarizes performance over a standardized cooling season, while EER2 focuses on a defined operating point. That can make EER2 useful when comparing full-load efficiency under hot-weather rating conditions.
As with SEER2, an EER2 value may describe a tested or certified system combination rather than an individual split-system component.
Why it matters
Two systems with similar SEER2 ratings can still differ in full-load performance. EER2 provides another lens for comparing how efficiently systems operate at the specified rating condition.
Formula / Conversion
EER2 = cooling capacity (Btu/hr) ÷ electrical input (W)
Sources
HVACBird prioritizes government standards bodies, federal test procedures, and recognized HVAC certification organizations for technical definitions.
Electronic Code of Federal Regulations
Federal test-procedure requirements for central air conditioners and heat pumps, including SEER2, EER2, and HSPF2.
Air-Conditioning, Heating, and Refrigeration Institute (AHRI)
AHRI guidance on certified matched systems, reference numbers, and third-party performance verification.
Related HVAC Terms
SEER2
A seasonal cooling-efficiency rating used for central air conditioners and heat pumps.
HSPF2
A seasonal heating-efficiency rating for air-source heat pumps.
COP
A dimensionless ratio comparing useful heating or cooling delivered with the work supplied to the system.
Matched System
A specific combination of HVAC components evaluated together as one system.