Efficiency ratings of 85% AFUE;Heavy-gauge steel heat exchanger-allows air to glide evenly over its smooth surface for maximum heating efficiency;Variable speed operation-assures comfort, effeciency and considerable noise reduction;Silentcomfort technology-ensures quiet operation;Innovative combustion chamber-constructed from alumina-silica ceramic fiber, provides quiet operation and high efficiency;Beckett burner-delivers super-efficient combustion for greater fuel economy;Heavy-duty fuel pump-provides quiet, reliable operation with fast shutoff of oil flow