Furnace Efficiency Ratings – Understanding AFUE
If you’re looking for a way to predict just how much your efficient gas furnace can save you, you need to understand efficiency ratings. The main efficiency ratings for all heating and air equipment are SEER, EER, HSPF, and AFUE. For furnaces, we’ll focus on AFUE.
AFUE, or the Annual Fuel Utilization Efficiency, is a percentage that measures just how much of the energy that is put into a gas furnace is useful heating power – the greater the percentage, the better. Currently, minimum efficiency requirements for AFUE are 80%. But, gas furnaces can reach much higher levels of efficiency – even approaching 100% AFUE! So, say a gas furnace is 97% AFUE. That means that 97% of the energy (natural gas) that is put into the system is returned in heating power.
Just make sure if you make that investment in a furnace that is nearly 100% efficient, you are taking 
steps to ensure you are getting your money’s worth. Keep up with regular maintenance, register your warranty and get the home comfort additions to support high-efficiency operation (like a programmable thermostat or a zoning system).
Have you done your research on high-efficiency furnaces? If you’re thinking of purchasing one, make sure you get in tough with your local gas furnace contractor.