Bryant’s Preferred series high efficiency gas furnace utilizes two stage operation in an effort to minimize noise, balance temperatures throughout the home, reduce temperature swings between heating cycles, reduce draftiness, provide you with cleaner indoor air, and preserve the life of the unit with fewer on and offs. In addition, the Preferred high efficiency model incorporates a second set of heat exchangers for greater energy efficiency above the Preferred 80% efficiency. Bryant has also incorporated electrically efficient, variable speed fan motors on the Preferred series furnaces, making them even more cost efficient to operate.