What is involved in getting your furnace serviced?

along with changing your filer every 2 months you should have the furnace serviced or [clean and checked]because they will check for cracked heat exchanger.oil the moter,adjust air/gas mixture,and visually inspect the various safety switch's.it should cost about 50.00 for the service .as for the ducts being cleaned they will cover your air returns with cardboard .and put a vacuum to the supply registers.they also can add deodorizers and sanitizers.for about 200.00 .