SEER Ratings – What Do They Mean?

What does SEER stand for?

The word SEER is an acronym for Season Energy Efficiency Ratio.

What is a SEER rating?

The SEER rating of an air conditioning unit is the cooling output during a typical cooling season divided by the total electric energy input during the same period. SEER is simply a formula that is described by the outcome of the following: Divide the system’s rated BTU’s (what ton the unit is, ex: 5 ton), by it’s stated SEER rating to determine how many watts it consumes per hour.

Why is knowing this information important?

This is one of the most frequently asked questions by a customer when they are deciding on what type of SEER air conditioning unit they should buy. There are numerous reasons why the customer should know what kind of SEER unit they need to buy. One of the main reasons a customer needs to concern themselves with is the operating cost annually of the unit. Everyone is always looking to save money and as a homeowner, you should know that the main source of your electric bill is your air conditioning unit; so why wouldn’t you want to save the most money possible right? Here in the next section, I’ll teach you the annual cost of different types of SEER units, so you can determine which unit best fits your budget.


In this section, I will teach you how to find the annual cost of a hypothetical air conditioning unit. The information we need to get started will be the size and SEER of the current air conditioning unit. For this example, we will use a 5 ton, 15 seer unit.

First, 1 Ton is the equivalent to 12,000 BTU’s (British Thermal Unit). So what we will do is take12,000 BTU’s and multiply that by 5 (that’s what Ton our unit is) and we will get 60,000 BTU’stotal. Now that we have the total number of BTU’s for our 5 ton unit, we will take 60,000 and divide that by 15 (that’s the SEER rating of our unit), you can find the information on what ton and SEER rating your air conditioning system is, by going outside and looking at the nameplate on your air conditioning unit. Digressing back to our formula, we will take 60,000 BTU’s and divide that by 15to get 4,000. The value 4,000 represents the number of Watts our air conditioning unit uses per hour of operation.

Second, we need to convert our Watts into KWH (Kilo Watts per Hour). The reason we need to do this is so that we can determine how many KWH our air conditioner uses per hour. By taking a look at your energy bill, you will see you are billed by KWH and not Watts. Going back to our equation, we will take 4,000 and divide that by 1,000 (1 Kilowatt = 1,000 Watts) and we will get 4. The number 4 represents the number of KWH our AC unit uses per hour of operation.

According to EIA.Gov and, the average Houstonian uses 1,262 kwh a month and15,144 kwh yearly. Click Here for charts and graphs of this data. For the sake of arguments and keeping things simple, let’s just say the average person in Houston uses their AC unit 8 hours a day. 8 hours multiplied by 30 (I just used an average of 30 days in a single month) and we get 240 hours used in a single month. Next, we will take the 240 hours we just received and multiply that by 12 (the number of months in a year) and we get 2,880. This new number (2,880) represents the number of operation hours our hypothetical AC unit uses annually. Finally, we will take 2,880 and multiply that by 4 (remember this number? It was the number of KWH our air conditioning unit uses per hour of operation) and we will get 11,520 kwh. This new number (11,520) represents the number of KWH our air conditioning system uses annually.

Lastly, now that we have the number of kwh our AC unit uses annually (11,520), we will take that number and multiply it by the dollar amount our energy companies charge us per kwh. For the sake of keeping things simple once again, we will just say our energy company charges us 10 cents per kwh. So, we will take 11,520 and multiply that by 10 cents and we will get 1,152 or in other words,$1,152.00 annually for the cost of operation for a 5 ton 15 SEER unit.

Now remember, this is all hypothetical. I just wanted to give you a foundation and a platform to work with. Now you can take all this information here and input your own data and see how this applies to you. Below are some charts displaying how different SEER units can save you money and energy.