If it comes to heating your home you want to use the most energy efficient alternative available to you. It’s probably a version while there are a huge proportion of homes which use their houses to heat if it was created before 1992. That is because the Annual Fuel Utilization Efficiency (AFUE) ratings were not assigned until 1992 and before then forced air furnaces were not regulated. However, forced air furnaces that are modern must satisfy an AFUE rating of 78 percent or higher in order to be marketed. Every year, higher rated units are regarded as high-efficiency models and will save you up.