No matter how much you would like the current furnace in your home to be the only one you’ll ever need, eventually, a time will come when continuing to have it repaired and maintained is throwing money away. There are several warning signs about a furnace that’s over-the-hill, but the easiest metric is its age. (If you don’t know the furnace’s manufacture date, check on the metal plate on the unit.)
The age when a furnace is considered “old” is 15 years, although well-cared-for units sometimes make it to 20 years. We recommend you give serious consideration to replacing a furnace that’s older than 15. Below are the reasons an older furnace can be a problem.