Ask the Expert
Q What is a condensing appliance?
A When a fuel, in this case natural gas, is burned, there is a temperature known as the dew point. In a conventional appliance, the gas is burned, and the flue temperature must stay hot above the dew point (aprox.425 degrees Fahrenheit). If the exhaust is below this temperature, the products of combustion start to condense. This can be very dangerous in conventional appliances causing rust in heat exchangers and in the chimney system. For this reason, the chimneys are hot which equates to a lot of lost heat and energy going up the chimney. In a condensing appliance, the maximum heat is extracted from the combustion process causing it to "condense" and drain out the appliance. The chimneys are cool to the touch with little or no clearance required. The heat has been used doing its job rather than just going up the chimney.