Choosing to replace or repair the furnace can involve several factors. This includes age, the issues that prevent proper functioning, and more.  If the repair is minor and occurs in a 10-year-old furnace or younger, it makes sense to repair it.  However, if the furnace is more than 15 years old and requires an extremely costly repair that may not succeed, it may be time to hire a furnace replacement in Kentwood, MI.