The general rule for furnaces is that replacements are most often needed every 15 to 20 years. Within that age range, most furnaces will be worn out and probably damaged in enough small ways so that they will not operate efficiently. Replacement may be required after 15 years, especially if they are not maintenanced regularly. Lack of maintenance and efficiency can lead to higher energy bills, but it can also seriously affect the air quality of your home. If you're finding that your home always feels really dry, stuffy, and you feel more tired and sick all the time, you should look into replacing your furnace. Here's how old furnaces ruin the air quality of your home.
