The furnace in your home provides a valuable service to all who live in the house. Obviously, the furnace keeps you warm in the winter, helps keep the pipes from freezing, and allows everyone to get a good night's sleep in January without having to crawl under the covers in a full set of winter clothes, mittens, and heavy socks. In the summertime, the furnace (or, more specifically, the circulating fan and blower motor inside the furnace) helps keep the air in the house cool and inviting. Yes, the days before we had heating and cooling systems in the house were unpleasant indeed. But, as mentioned earlier, the furnace performs a number of services. One of the often-overlooked services is in filtering the air we breathe in the home. And the quality of the air is directly related to how often you change your furnace filter.