Modern forced-air heating systems have two complete sets of ducting for movement of heated and cooled air from the home. And comfortable air ducting exits the furnace just downstream with the furnace heat exchanger. Air is blown across the heat exchanger from the furnace fan, which heats it before it enters the ducting and it

Modern forced-air heating systems have two complete sets of ducting for movement of heated and cooled air with the home. And comfortable air ducting exits the furnace just downstream of the furnace heat exchanger. Air is blown round the heat exchanger with the furnace fan, which heats it before it enters the ducting and is

Modern forced-air heating systems have two complete sets of ducting for movement of heated and cooled air through the home. The warm air ducting exits the furnace just downstream of the furnace heat exchanger. Air is blown throughout the heat exchanger from the furnace fan, which heats it before it enters the ducting and is