The answer to 'how often to replace central air' is that most central air conditioning systems should be replaced every 10-15 years. Central air conditioners have an average lifespan of 15-20 years, but the efficiency and performance can start to decline after about 10 years of use. Factors like regular maintenance, usage, and local climate conditions can impact the system's longevity.
As your central air unit ages, it may become less efficient, require more frequent repairs, and cost more to operate. Replacing an older, less efficient system can provide significant energy savings and improved home comfort. It's generally recommended to start planning for a replacement when your unit is 10-12 years old.