When temperatures start to rise, having a working air conditioner is key. In fact, in parts of the country, not having a working air conditioner during the hotter months can lead to dangerously high temperatures inside the home. While air conditioners are built to last for a while, eventually they will need replacement. The average lifespan of an air conditioner is between 15 and 20 years. If your air conditioner is in need of repairs often or is getting older, it's likely time to consider replacement.