There are two prominent types of furnaces in your everyday household — the conventional furnace and the high efficient condensing furnace. Both types are efficient at keeping your house warm. However, the latter is much more efficient with an efficiency score of over 90 percent AFUE. AFUE refers to the standard measurement of furnace efficiency.
Those of us that have experience with conventional furnaces know that you can easily burn your fingers on the hot exhaust vent. In contrast, a condensing furnace stays warm instead of piping hot. This is due to its highly efficient system, which extracts more heat from the combustion process.
But how exactly does a condensing furnace work, and what makes it so different from the conventional furnace?These two systems have a lot in common. Both filter cold air returned from the house, while a circulating fan is used to move the air and heat it with a gas burner, which is controlled by an electronic ignition.
The main difference between the two is in the heat exchanger technology that “harvests” the heat from the combustion process and the process used to deplete the resulting gases. These processes are the most important factors in the varying efficiency of the two furnaces. It’s not that the condensing furnace has a more efficient combustion process, but rather it has a more effective heat extraction process.
Conventional furnaces make poor use of the combustion gases, with a good bit of the gases exiting the chimney flue prior to cooling. The conventional furnace’s more efficient counterpart keeps extracting heat from the gases even after they’ve chilled and condensed. It accomplishes this by using two heat exchangers. The second exchanger system was designed to handle corrosive condensed exhaust gases produced from water and carbon dioxide. These gases are “harvested” for their heat until condensed water drips from the furnace’s heat exchangers.
For more professional advice about furnace systems and other problems related to home comfort, please contact Roth Heating & Cooling today. We’ve been serving the Aurora area since 1976.