CSLB C-20 HVAC ContractorCooling and RefrigerationHard
A manufacturer's spec sheet lists a packaged air conditioning unit with a cooling capacity of 36,000 Btu/h while drawing 3,000 watts of electrical input at rated test conditions. What is the unit's EER?
- A14.4
- B9
- C10.8
- D12
Show answer & explanationAnswer & explanation
Correct answer: D. 12
EER is calculated as cooling capacity in Btu/h divided by power input in watts: 36,000 Btu/h ÷ 3,000 W = 12 EER. This single-point efficiency rating is measured at a fixed outdoor temperature (95°F) unlike the seasonal SEER/SEER2 metrics.
Why the other options are wrong
- A. This value results from an incorrect division, not matching the given numbers.
- B. This value results from an incorrect division, not matching the given numbers.
- C. This value results from an incorrect division, not matching the given numbers.
EER Calculation
EER (Energy Efficiency Ratio) is calculated by dividing cooling output in Btu/h by electrical input in watts at a single fixed test condition (95°F outdoor temperature).
- EER = Btu/h output ÷ Watts input
- Measured at one fixed outdoor temperature, unlike seasonal SEER/SEER2
- Higher EER indicates better efficiency at that specific condition
- Often used to evaluate peak-condition performance, important in hot climates
Memory trick: Btu over watts, straight math gets the EER shot.