When comparing equipment one of the biggest considerations is the SEER and EER rating as it measures the efficiency of the air conditioner. SEER, Seasonal Energy Efficiency Ratio, measures how efficiently a cooling system will operate over an entire season. The higher the SEER, the more efficient the air conditioner.

EER, Energy Efficiency Ratio, is a measure of how efficiently a cooling system will operate when the outdoor temperature is at a specific level (95F). Again, the higher the EER, the more efficient the air conditioner.

Both SEER and EER are included in the ENERGY STAR specification because each rating indicates the energy efficiency of the product under different operating modes. SEER rating more accurately reflects overall system efficiency on a seasonal basis and EER reflects the system’s energy efficiency at peak day operations. Both ratings are important when choosing a product.

As of January 2006, all air conditioners sold in the United States must have a SEER of at least 13. ENERGY STAR qualified Central Air Conditioners must have a SEER of at least 14. Substantial energy savings can be obtained from more efficient systems. For example by upgrading from SEER 9 to SEER 13, the power consumption is reduced by 30% (equal to 1 - 9/13). This can be significant depending on the usage rate and the cost of electricity.

I know we try to keep these newsletters non-technical but I wanted to provide one quick calculation that would help you better understand potential savings:

Annual Cost = (Tons (BTU/h) * Operating Hours * Cost (kW/h)) divided by (SEER (BTU/W hr) * 1000 (W/kW))

If I have 5 ton air conditioning unit (there are 12,000 BTU/h per ton) that runs 2,000 hours a year at a rate of $0.14 kW/hr having a 10 SEER, then I can expect to spend $1680 a year to cool my home. (60,000 * 2,000 * 0.14 / (10 * 1000))

If I decide to upgrade to a 13 SEER unit, then my annual expense would drop to $1292, a savings of $388 per year.

However, before you go and upgrade to a new unit, please consider your particular situation. You need to consider your home, local climate, expected longevity, usage, and electricity rate when selecting the appropriate SEER equipment. For example, if you only run your air conditioner for 500 hours a year, then it would not be cost effective to get a higher SEER.

Furthermore, sometimes it is more cost effective to keep an existing unit if the existing air conditioner has been properly maintained. Maintenance when performed regularly can significantly help keep efficiencies as high as possible.

Deciding to upgrade versus maintaining existing equipment depends on a number of factors and should be discussed with a technician with experience in your local area and climate and that has conducted a thorough examination of your equipment. For most situations, the minimum or near-minimum SEER units are most cost effective, but the longer the cooling seasons, the higher the electricity costs, and the longer the purchasers will own the systems, incrementally higher SEER units are justified.

Have a great week,
Paul Hall, Total Comfort A/C Systems, and
Brian Starzec, Pollex and Starzec, LLC

Next Issue - We will talk about a technology that may change heating and cooling for years to come.

I hope you enjoyed this article. Please feel free to email your comments to brian@acpatriot.com. Please remember to forward this newsletter to friends, family and neighbors.