SEER / EER Rating Calculator
Calculate the Seasonal Energy Efficiency Ratio (SEER) and Energy Efficiency Ratio (EER) for air conditioning and heat pump systems. Convert between SEER and EER, or compute ratings from cooling output and power input.
Mode 1 — Compute SEER & EER from System Data
Mode 2 — Convert Between SEER and EER
Formulas
EER (Energy Efficiency Ratio)
EER = Cooling Output (BTU/hr) ÷ Power Input (Watts)
Measured at a single steady-state condition: 95°F outdoor / 80°F indoor / 50% RH.
SEER (Seasonal Energy Efficiency Ratio)
SEER = Total Seasonal Cooling Output (BTU) ÷ Total Seasonal Energy Input (Wh)
= [BTU/hr × Operating Hours] ÷ [kWh × 1,000]
Represents performance across a full cooling season with varying temperatures.
SEER ↔ EER Conversion (AHRI 210/240 approximation)
EER ≈ SEER × 0.875
SEER ≈ EER ÷ 0.875
The factor 0.875 accounts for part-load operation and seasonal temperature variation.
Cooling Capacity in Tons
Tons = BTU/hr ÷ 12,000