Before Upgrading Your A/C, Understand These 3 Important Efficiency Ratings
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Before Upgrading Your A/C, Understand These 3 Important Efficiency Ratings


When you’re selecting a new cooling system, look carefully at its A/C efficiency ratings. The U.S. Department of Energy requires ratings on these appliances to inform consumers about energy consumption. The ratings include:

The most common rating you’ll find for central air conditioners and heat pumps is its SEER (seasonal energy efficiency ratio) rating. Each model of these systems is tested over the course of a season. Engineers place the outdoor condenser in an environment that’s held at 82 degrees F and measure the amount of electricity the equipment uses to cool a space to 80 degrees with a humidity of 50 percent. The SEER rating runs from 13 into the 20s, and each increase indicates it uses 10 percent less energy under lab testing conditions.

Portable and window cooling appliances have an EER (energy efficiency ratio) rating that’s similar to the SEER, but tested differently. Instead of holding the temperature at 82 degrees, they raise it to 95 degrees for a shorter period and base the rating on electrical consumption. The EER rating is available for central heat pumps and air conditioners, but isn’t always prominently displayed. The minimum EER stands at 9.7 for portable devices.

The last of the A/C efficiency ratings is the COP (coefficient of performance). It measures how much heat the system removes based on the amount of electricity it uses. The easiest way to learn the COP is to calculate it by dividing the EER by 3.41. If you select an air conditioner whose EER is 12, its COP would be 3.5, indicating it moves three and a half times the heat per unit of energy it consumes. Higher COP ratings indicate better efficiency.

When choosing an air conditioner, the ratings tell you the energy consumption of the system. Other factors, like how it’s sized and installed also make a difference in the energy it ultimately uses.

The pros at Roth Heating & Cooling can help you learn more about A/C efficiency ratings and getting the best performance from a new system. We’ve provided HVAC services for the greater Portland area since 1976.

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