The average life expectancy of furnaces in homes today is between 16 and 20 years. If your furnace is close to this age or older, you have had problems with it, or you are concerned about excess energy consumption, you should begin shopping. Shopping for a replacement furnace in an emergency does not allow time to make your best decision. There are many furnace makes out there, but they are not created equally. The price of a new furnace does not reflect its value. Researching contractor, the manufacture, their reputation, and the features that will satisfy your requirements will help to choose which furnace will provide the best value. The lowest price is usually the lowest for a reason!