Air Conditioning Efficiency

>Ken: This week we will be talking about air conditioning, and how it affects your utility bill. First, the older your unit, the more it will cost you to run it. Think of it as you would your car, the higher the gas mileage the cheaper it is to operate. The same with your AC, the higher your SEER rating of the unit, the cheaper it is to operate. the SEER of your unit could be anywhere from 1-20, depending on the original SEER rating, age and condition of the unit. The condition of the ducting can also affect it, but we will discuss that in a later blog. So if your unit runs at 6 SEER, and you purchase a 12 SEER unit, you just cut the cost of operating your AC in half.

>Jason: Secondly, what is SEER? SEER stands for the Seasonal Energy Efficiency Rating. This rating is an average of the yearly usage of a unit, assuming that the AC is run all the time. Of course this figure is based on laboratory tests where the AC is cooling 82 degree air to 80 degrees. Since this isn't hard to accomplish, the SEER is generally higher than an Air Conditioner can actually perform. What's worse is that this lab test can vary depending on the company performing it. That is why there is another rating available, which is simply the EER, or the Energy Efficiency Rating. This is a standardized test in which an Air conditioner is cooling 95 degree air to 80 degrees constant. The EER is thus always a lower, but more accurate number. When purchasing a new air conditioner however, the EER is not posted except in the specifications of the unit. So when shopping for an AC, you can usually count on a 2-3 point loss between SEER and EER. How high of an EER should you purchase? Well, that can only be answered by your budget. Federal Government regulates that no unit can be manufactured below 13 SEER, which is more like 11 EER. However, if your pocketbook can afford it, you may want to look at getting a higher efficiency unit. Remember that this rating is like the gas mileage on your car.

>Ken: There are other factors to consider with how efficiently your AC will run, but we will discuss those later. An interesting calculator showing how the different efficiencies may affect your utility bill can be found at The following AC calculator The type of AC unit you have will also have a bearing on how efficient a new unit can be when purchasing, but again, we will discuss that at another time.

>Jason: In closing, if you decide that its time to purchase a new air conditioner, be sure to question your contractor about the EER of the unit, and make sure that the contractor sizes the unit properly using a heat load calculation.