A well-maintained furnace lasts an average of 25 years or more. If your furnace is nearing the end of its useful life, it might be time to update your central heating system to improve your family’s comfort and keep utility bills in check, or maintain your home value in anticipation of a sale. If you’re simply looking for ways to increase the value of your property, however, replacing a working furnace may not always be the best financial investment for your future.