Ever since the energy crisis of the 70s, a lot of attention has been paid to the efficiency of heating and cooling systems. Manufacturers have found it necessary (both for marketing and regulatory reasons) to make their air conditioning systems as efficient as possible. As a part of this, the EER and SEER rating systems were developed to provide a method for comparing the efficiency of one air conditioning system with another. If you're thinking about purchasing a new air conditioner (whether it's a window AC or a whole house unit, from outlets such as Tropic Air Conditioning INC), it's important to understand the efficiency rating system. This will help you make a better informed purchasing decision.
The EER System
EER stands for "energy efficiency ratio" and represents the ratio of the cooling you will get (in BTUs) to the total amount of electricity (in watts) you will use. This ratio is based on a scenario in which the temperature of the home is 80°F, the temperature outside is 95°F and the air conditioning system or unit is operating at its maximum efficiency (known as the steady-state efficiency). This is the system that was first used to compare the efficiency of one air-conditioner with another.
The SEER System
SEER stands for "seasonal energy efficiency ratio." This is the ratio of the cooling you will get over a full year to the amount of electricity you will use. The purpose of this newer system is to give consumers a more real-world comparison that's easier to understand than the EER system. Again, the units being measured are BTUs and watt hours.
Differences Between Seer and EER
The primary difference between EER and SEER is that EER provides you with a measurement of the efficiency of the unit at a particular point in time, while SEER looks at the efficiency over a full season. While both systems arrive at their efficiency ratings using similar methods, the SEER method is generally considered easier for consumers to understand and has become the standard approach for most air conditioning systems. However, some window air conditioners still use the EER system.
How to Compare Efficiencies
With its old-style compressors and larger number of moving parts, an old air conditioning unit might have an SEER rating of 6 or 7. Modern air conditioning systems usually have an SEER rating of about 13. Some manufacturers are able to get the efficiency of their units up to 14 or even higher. Keep in mind though that these ultrahigh efficiency units will cost much more than a unit with a rating of 13.