Furnaces - Introduction and History w/ Jim Bergmann

<p>Jim takes us all the way through the history of furnaces, from the Stone Age when he was a child to modern modulating condensing types.</p> <p>The goal of a furnace is to move heat, so a furnace uses heat exchangers to facilitate heat transfer. Furnaces have primary and secondary air. The primary air goes through the burner, and the secondary air goes around the flame and is pulled in around the heat exchanger inlet. So, the flame's heat creates a draft that pulls air in.</p> <p>Natural gas and oil (LP/propane) furnaces are common nowadays...