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Kilowatt Heating, Air Conditioning and Electrical Blog

Customer Question: “What’s the Difference between SEER and EER?”

question-markWhen you start the quest to have a new air conditioning system installed in your home (and right now is a good time to have it done; we’re coming up on the hot days of summer) you’ll encounter numerous numbers and stats. It can all be a bit confusing. You probably already know that BTUs has something to do with how much cooling an air conditioner can put out. The higher the BTUs, the more cooling power the AC has. Technically, BTUs are a measure of how much heat the AC can remove from the air—but the effect is the same as far your comfort is concerned.

But what about the two efficiency ratings you find on the list of an air conditioner’s stats, SEER and EER? You might know that the higher these numbers, the more energy efficient the air conditioner is. But what’s the difference between the two numbers? Why the extra “S” on SEER? What does it mean, and is it important?

First, A Word of Caution

Although we can help you understand the difference between SEER and EER, you shouldn’t attempt to make a final choice for a new air conditioning system on your own. For new air conditioning installation in Van Nuys, CA or elsewhere in Los Angeles and the San Fernando Valley, you want certified HVAC professionals helping you. Finding the right balance of efficiency and size is critical for receiving a new cooling system that will do exactly the job you need from it for many years to come. You can depend on our exceptional employees to come through for you.

And Now… SEER vs. EER

The efficiency of an air conditioning system is how well the unit converts the electrical power it consumes into actual indoor cooling. The standard measure of this is EER, or energy efficiency ratio. The ratio is determined by dividing the AC unit’s cooling output (measured in BTUs, or British Thermal Units, removed from the air) by the amount of electricity consumed (measured in watt-hours). The test to calculate EER is done under specific conditions: indoor temperature of 80°F, outdoor of 95°F, and 50% humidity. This gives a “spot check” for system’s basic efficiency.

SEER is almost identical: cooling output divided by electricity consumed, using the same units of measurement. The difference is that instead of making a single test under specific conditions, the calculation is done over an entire season with a range of conditions, with temperatures from 64°F to 105°F, and humidity from extremely dry to highly humid. This is where the “S” in “SEER” comes into play: seasonal energy efficiency ratio. SEER gives an average for the system’s efficiency over a summer season of use.

Which Is More Important?

They’re both important. SEER will always be higher than EER, and in general SEER provides a sense of how much you might save during a summer of air conditioning. But EER is a good snapshot of how the system will work during peak summer conditions. The ENERGY STAR program has a set of minimum standards for both efficiencies, and this is a good place to start when thinking about how efficient a system you want.

Kilowatt Heating, Air Conditioning and Electrical has the professionally trained employees to take care of your HVAC needs. Call our certified service technicians 24/7 for exceptional customer service!

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