Older furnaces can waste even more.
By taking advantage of the latest technology and installing a new high efficiency furnace you can save energy dollars and improve comfort. The AFUE indicates the percentage of fuel turned into heat. The higher the AFUE, the more efficient the unit and more energy dollars you can save. High efficiency furnaces tend to be slightly more expensive than the standard type, however the additional cost is offset by the increased energy savings. New residential furnaces are required to display an EnergyGuide label which compares annual fuel costs with those of other similar sized units.