What are EER and SEER?

EER and SEER are two more factors to consider when purchasing your new air conditioner or HVAC appliance. Unfortunately, knowing which unit to buy can depend on more factors than most people want to deal with. The purchase of an incorrect air conditioner can be an expensive and hazardous mistake.

Both EER and SEER offer a way of describing the energy efficiency of a given air conditioning appliance. The higher the number, the more energy efficiency and thus the less it will cost you to run it for a year. Smaller air conditioners usually have a top EER of about 11, and bigger air conditioning units can top out with an EER of about 13. A larger HVAC system will display an SEER rating – these are always higher numbers – but they should not be confused.

What does EER and SEER Stand for?

EER is generally used for smaller air conditioners and window mounted units. SEER is almost the same measure but more commonly used on central HVAC systems and larger central air conditioners. EER stands for Energy Efficiency Ratio while SEER stands for Seasonal Energy Efficiency Ratio. Both of them are based on the total BTU (Britsh Thermal Unit) output per hour divided by the watts of electricity consumed.

The important difference is that EER is calculated for a smaller controlled environment such as a room or apartment. SEER, on the other hand, is calculated by including numbers for the cycling of the unit on and off and seasonal temperature variations where the unit is likely to be installed. Temperature and humidity can therefore be important to the the relationship between the two measures.

eer and seer enery guide labelEER is calculated assuming a 95 degrees outside temperature and an inside temp of 80 degrees at 50% relative humidity. SEER is calculated at the same indoor temperature, but at between 65 and 104 degrees outside temperature to simulate seasonal variations.

A really good consumer guide will calculate annual costs for running air conditioning based on the cost of electricity in your area and the EER or SEER ratings of the air conditioning appliances being reviewed or sold. If you’ve ever gotten knocked out by an electricity bill, you’ll know why this is important.

Usually the yellow Energy Guide label  in the store estimate costs based on a national average of 8.4 cents per kilowatt-hour which makes for very low cost estimates, if not for bad air conditioning unit sales.

One of the mistakes consumers commonly make is in determining exactly how much cooling capacity you need. As opposed to EER, cooling capacity is written in the store as BTU/hour units; the higher the number the higher the cooling capacity.

Getting an air conditioner as close to the correct cooling capacity as possible is important. Energy efficiency and correct cooling capacity go hand in hand when it comes to saving on electricity and still being comfortable. If you’re thinking or replacing your air conditioning or your HVAC system, give us a call. We’ll be happy to discuss a machine rated appropriately for New York City and for the size and use of the building or apartment you’re hoping to cool.

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Filed under: Energy Efficiency