Seasonal Energy Efficiency (SEER)

SEER measures how much cooling an air-conditioning system delivers over an entire cooling season for each unit of electrical energy it consumes. It works as a seasonal ratio, so a higher SEER means the system provides more BTUs of cooling for the same electrical input, which usually indicates better efficiency in real-world use than a single point test would show. Because it is based on seasonal totals, it helps compare systems under conditions that better reflect typical operation over time.

Use this formula when comparing the efficiency of air conditioners, heat pumps in cooling mode, or other refrigeration systems over a full season. It is useful for estimating how effectively a system converts electrical energy into cooling output and for comparing different equipment ratings.

• Using watts instead of watt-hours; SEER needs energy, not power
• Mixing monthly or daily values without making sure both totals cover the same season
• Forgetting that SEER is a ratio, so the units are BTU per Wh rather than a plain number with no meaning