Aug 09 , 2016


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SEER is probably the least understood concept.  It stands for Seasonal Energy Efficiency Ratio, but that probably doesn’t help you much. The SEER rating is the resulting number that is applied to an air conditioner. Therefore, the higher the SEER rating then the more energy efficient a given air conditioner unit should be.

But how do you determine what SEER level is high enough for your home? Given a choice of 5 different SEER rating which one should you select? SEER ratings can run between the federal minimum of 13 SEER to the extreme high of 23 SEER.

SEER is simply a formula that is described by the outcome of the following:

Divide the system’s rated BTU’s by the unit’s stated SEER rating to determine how many watts it consumes per hour, (Kwh stands for kilo-watt hour).

Here’s the formula (our example will use 15 SEER):

36,000 Btu’s divided by 15 SEER = 2,400 watts

The 2,400 represents the number of watts consumed each operating hour by the system.

In order to determine which SEER rating choice is best for you by determining your annual operating cost. You need to determine how many hours, on average, your system will operate. Let’s assume you set your thermostat at 78 degrees most of the time and your home has fairly good insulation. And average use in Arizona is 2,500 hours of operation annually.

Take the number of watts from above formula (2,400) and multiple the annual operation hours (2,500)

2400 hours of operation times 2500 watts consumed per hour equals 6,000,0000

That’s a lot of zeros…now turn the number into Kwh by dividing the total watts consumed per hour (2500) by 1000, which equals 2.5 ~ 2500 divided by 1000 = 2.5

This new number (2.5) represents the number of watts your system consumes hourly, expressed in one thousand watt units, or in this case 2.5 of these thousand watt units (Kwh)

2400 hours of operation X 2.5 Kwh consumed per hour = 6000 KWH consumed by our example air conditioner annually.

Using the above formulas and a handy calculator, you can convert this into a figure used by your power company to calculate your electric bill by looking at your current bill and determine the Kwh cost used.  For example: 6000 x 11.5 cents cost per Kwh from your electric bill = 690 or $690.00 annual cost of operation for a 3 ton, 15 SEER air conditioner.

Feel free to contact us to help you sort through the SEER ratings and determine the best for your home at 520-399-5850.