Managing Member of Lucky Duct, LLC.
Be leery of the estimator that is in and out of your home in 30 minutes or less, because getting it right during the estimate phase will have a huge effect on achieving maximum efficiency of the furnace and your over all indoor comfort for many years to come. That all came to an end when Rheem manufacturing designed their new line of 95% AFUE 2 stage furnaces. The two stage gas valve emerged to where a low fire predominately occurs on temperate (less cold) winter days saving an additional 25-35% on gas consumption and then when the weather gets real cold outside the furnace can engage a high fire to ensure that the appliance can keep up with heating your home only when high fire is truly needed, to ensure that the homeowner gets the best of both worlds; saving money and staying comfortable. The two heat exchanger design is the key feature that allows a 90%+ AFUE furnace to operate so efficiently. Not only is the Rheem 90%+ AFUE line of furnaces tougher and built with cost effective parts in mind, but they even went as far as ensuring that all Rheem furnaces operate at a vastly lower decibal range making the Rheem furnace the quietest class of furnaces in the residential market today. Remarkably after 70 years of relatively little change in the heating market in terms of how a furnace basically operated, a vastly more efficient appliance emerged on the market. The venting of a 90%+ AFUE furnace is typically done with PVC piping material and most often is vented to the exterior side of a home. So engineers went to work to produce the two heat exchanger furnace and incorporated a secondary heat exchanger that looks like a coil to capture the hot flue gas moisture to re use this heat in a more efficient appliance, rather than wasting this heat out of the flue pipe. 90%+ AFUE furnaces have a 2 heat exchanger design to avoid wasting heat, in the past the product was problematic when it was first developed in the 90’s, but has since been improved to near perfection today by most manufacturers to be a very reliable product and if sized properly and installed properly will save an incredible amount of money on the utility bill that you can capitalize on year in and year out. A primary heat exchanger handles the ignition of the furnace and the natural gas fire (propane, kerosene, heating oil or what ever the furnace burns) of the furnace burners. Furthermore, Rheem realized that the primary heat exchanger was the most expensive part of the furnace, so they decided to make a primary heat exchanger tougher than any other manufacturers primary heat exchanger. There are many like minded good companies and contractors out there that conduct themselves that way as well. With a conventional 60-80% AFUE furnace that is all that is present for a heat exchanger, but through brilliant engineering furnace manufacturers realized that flue gases always creates hot moisture that is typically wasted out of the flue pipe and so they decided to capture this free energy by designing a better product. Eliminating seam points on the heat exchanger increases the life span of the part. Most of the estimates that reputable heating and air conditioning companies perform may require between 1-2 hours to gather all necessary data, answer customer questions and to write an up front price to do the work. Carrier, Trane, American Standard and Lennox furnaces will work and if sized and installed properly will last for many years, however when they break, you will surly pay a pretty penny to get them fixed.