How to Calculate Energy Efficiency Ratio
What is Energy Efficiency Ratio?
Energy Efficiency Ratio Calculator helps contractors and tradespeople accurately size, spec, and estimate materials and systems.
Formula
EER = Cooling Capacity (BTU/hr) / Power Input (Watts)
Step-by-Step Guide
- 1Check equipment nameplate for BTU and wattage
- 2Apply the formula using your project measurements
- 3Add required safety factors or waste allowances per code
Worked Examples
Input
12,000 BTU AC, 1200W power input
Result
EER = 12000/1200 = 10 (SEER translates to seasonal EER)
Common Mistakes to Avoid
- ✕Not applying code-required safety factors or derating
- ✕Forgetting to account for waste and cut losses in material estimates
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