If your furnace is older than 15-20 years, it is time to consider having a new furnace installed. Signs that your furnace is ageing include excessive noise during operation, reduced or delayed output of heat, and frequent breakdowns. If the annual cost of repairing your furnace is going to be more than half the cost of a new furnace, it is going to be in your best interest to consider replacing the appliance. By installing a new furnace, you’ll benefit from the increased efficiency of a newer appliance and enjoy fewer issues, saving you money and headaches.