What Do Those HVAC Ratings Mean?

HVAC ratings

Have you ever been shopping for a new HVAC system and noticed acronyms like “EER,” “SEER,” “AFUE,” or “HSPF” in the unit details? If you don’t know what they mean, you should – all of these acronyms are rating systems that are used to score HVAC units on their efficiency. Here are more details from our HVAC contractors:


EER ratings, or “energy efficient ratio” ratings, were introduced in 1975 by the Air Conditioning & Refrigeration Institute (ACRI) and are applied to room air conditioners. To get the rating, experts calculate the cooling output of the unit (in BTU’s per hour) divided by the amount of electricity it uses. The higher the number rating, the more efficient the HVAC unit.


SEER ratings stem from EER ratings, however, they’re “seasonal” (hence the “S”). SEER ratings were introduced in 1978 after the ACRI realized that there are different seasonal conditions throughout the country. SEER ratings are applied to central HVAC units, but are calculated the same way EER ratings are. Again, the higher the number rating, the more efficient the HVAC unit.


If you’re shopping for a gas-fired or oil-fired furnace, water heater, or boiler, you’ll see an AFUE (“average fuel utilization efficiency”) rating. This rating is calculated in percentages using the division of BTU output by how much energy the unit uses. The higher the percentage, the more efficient the unit is.


When it comes to air-source heat pumps, look for the “heating seasonal performance factor” rating, or HSPF rating. Like the other ratings, a heat pump’s efficiency is measured by the ratio of BTU’s output per hour to the amount of electricity used. Higher numbers equals higher efficiency. In fact, heat pumps with very high efficiency (usually rated an 8 or higher) may even be considered for an energy tax credit.

If you have any other questions about HVAC ratings or about which type of unit is best for your home or business, give our HVAC contractors a call today.

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