I have been in the heating business for over thirty years and believe I am giving both a educated opinion as well as a honest one. Comfortmaker's ninety five precent efficient furnace is probably the best furnace in it's class. The reason I say this is in order to get this much efficiency out of a furnace it requires having two heat exchangers. Comfortmaker is currently the only manufacture that makes both heat exchangers out of stainless steel. The importance of this is when a furnace is this efficient, exhaust gases are well below boiling which causes all water that was turned to steam in combustion...