“I was told that the average life expectancy of an A/C System is only seven to ten years. How can this be? My System up north is twenty years old!”
While split air conditioning systems in northern areas of the country may have a longer lifespan in years, generally speaking, the actual run-time over a lifetime, in hours, is about the same. Of course, it will also make a difference if you’re comparing a location close to salt water, or to marshy areas, to that of an arid climate.
Here in southwest Florida, we’re both close to salt water and marshy areas. Additionally, we’re typically in peak cooling season for about 3-4 months and in just-under-peak conditions for another 5-6 months. This results in our cooling season lasting roughly 9-10 months. In addition to extended periods of high temperatures, our climate is also very humid (dry air cools far more quickly than moist air). All of these factors result in an average of 2,800 run-hours per year! In a typical year, it would be the equivalent of a 53+ hour work week, every week, or like putting over 100,000 miles on your car in a year! It’s hands-down, the most used, hardest working, appliance in your home.
Another factor that comes into play with lifespan is the continually changing regulations for increased efficiency of split air conditioning systems. A split system consists of an air handler inside (its primary components being the evaporator coil and blower motor) and an outdoor condensing unit (with its primary components being the condensing coil, compressor, and fan motor).
These two units, air handler and condenser, must be rated as a certified “match” per the Air Conditioning, Heating, and Refrigeration Institute (AHRI). Therefore, depending upon the age of the system, type of refrigerant it utilizes, and the efficiency rating (SEER, or EER); if the air handler or condensing unit suffers a major component failure (coil or compressor), it may not be possible to replace only that portion of the system (due to lack of a rated match). In these instances, the cost to replace the entire system is frequently a more economical choice than that of a very costly repair.
Meeting the higher efficiency ratings is achieved, in part, by being able to transfer heat faster (in less run-time hours). Thinner coils (than in older units) result in a more efficient exchange of heat. While this may result in the coils being more susceptible to wear and environmental corrosion, the decreased operating costs of new systems outweigh the expense of replacing an old system sooner, rather than later. According to FPL’s annual cooling cost comparison chart, the annual cost of operating a 3.0 Ton, 10-SEER system (typical of the 1990’s) is $1,009; whereas a current 20-SEER system is estimated to cost just $500 per year to operate. Based on those figures, over the course of ten years, the 10-SEER system would cost $5,090 more to operate.
AHRI: Air Conditioning, Heating and Refrigerant Institute
SEER: Seasonal Energy Efficiency Ratio (peak season; higher ratios indicate increased efficiency)
EER: Energy Efficiency Ratio (overall; higher ratios indicate increased efficiency)