One of the new innovations in gas furnace design is the placement of a second heat exchanger. Normally the heat exchanger takes in as much heat as it can hold before it is blown throughout the home. The excess follows the burnt gases up the chimney. With a condensing gas furnace these gases are passed by a second heat exchanger. As these gases cool they release more heat and then condense into a liquid that is sent to a drain. The result is that more heat goes into the heating system and not wasted up the chimney. Precision valves, electronic motors and Teflon bearings add to the smooth operation and further reduce energy consumption.