What is a SEER Rating
While the price tag might be the first thing many consumers look at when weighing their cooling system options, a unit's performance potential is also important. You amy ask, "What is a SEER rating?" A system's SEER rating – seasonal energy efficiency rating – serves as a performance guide. This rating denotes how efficiently an AC unit uses electricity to produce a cooling output – the higher the rating, the more efficient the system.
An old AC might have an SEER rating of less than 10, which is very inefficient by today’s standards. In fact, even regulations set before 2015 required systems to operate with at least 13 SEER. Since then, regulations have further tightened in certain areas. For example, if you live in a Southern state, your AC should have SEER ratings of at least 14.
To understand how SEER is calculated, you first need a brief definition of BTUs – British Thermal Units. A BTU represents the amount of necessary heat to raise a pound of water's temperature by one degree. For sufficient cooling, you need an AC that offers roughly 20 to 30 BTU per square foot of the room, although factors such as insulation, local climate, and direct sunlight also play a role.
SEER divides an AC unit’s BTU capacity by its wattage – essentially dividing its cooling power per hour by the amount of electricity it uses per hour. When measuring SEER, a range of temperatures is taken into account, hence providing a "seasonal" average. These temperatures can vary from as low as 65 degrees to as high as 104 degrees Fahrenheit.
Compared to EER
SEER isn’t the only rating scale out there for cooling systems. EER – the energy efficiency rating – provides another method of measuring how well your cooling unit performs. However, there are quite a few differences between EER and SEER, including what they specifically measure and how they are calculated.
EER is also calculated by dividing an AC’s BTU by the watts required for the unit to operate. However, unlike SEER, which is an average of a range of temperatures, EER is determined with the assumption of a steady temperature of 95 degrees Fahrenheit. This temperature best reflects how the system will function when it’s needed most – in the heat of summer. Because of this, the EER is most useful in states that see higher temperatures throughout the year.
Buying According to SEER
Regulations require systems to reveal their SEER, but not necessarily EER. So, when comparing your options, make sure you’re matching SEER to SEER, rather than comparing SEER to EER.
In addition, keep in mind that a system with a higher SEER air conditioner rating will likely come with a higher price tag as well. You are essentially making a larger investment that will lead to energy bill savings in the future. This is especially true if your living space is currently equipped with an outdated and inefficient HVAC system.