Seasonal energy efficiency ratio. It is expressed in Btu per watt-hour and calculated from lab tests at several outdoor temperatures and part-load points, so it rewards two-stage and variable-speed equipment. SEER2 uses test conditions with higher duct static pressure, which gives lower numbers for the same unit, so a SEER and a SEER2 figure should never be compared directly. US federal minimums are set by region, with a higher floor for split air conditioners installed in the Southeast and Southwest.
Customer wants the 20 SEER unit, but with those ducts it'll never see its rating, fix the static first.
Also heard as
- seasonal energy efficiency ratio
Do not mix it up with
- EER: SEER is a seasonal average including part-load operation; EER is a single full-load rating at a hot outdoor condition.
Related terms
EER
Energy efficiency ratio: cooling output in Btu per hour divided by watts of input at one hot, full-load test point.
HSPF
Heating seasonal performance factor: a heat pump's seasonal heating output in Btu divided by its electricity use in watt-hours.
COP
Coefficient of performance: heat moved or delivered for each unit of energy put in, with both measured in the same units.
Static pressure
The pressure air exerts outward on duct walls, the resistance a fan works against, measured in inches of water column.