Until recently, I had no knowledge of heat exchangers. I didn’t realize that it is probably the most important and expensive part of a gas furnace. I also never considered that failing to have my heating system professionally serviced would lead to such a huge problem and expense. My furnace was only six years old when it started to have issues. It was suddenly running for excessively long cycles yet failing to meet the thermostat setting. It simply isn’t putting out enough warm air to keep the house comfortable. I noticed that the rooms of the house were all different temperatures. There was a significant amount of dust floating around and an unpleasant smell. I should have called for professional repair immediately. I kept hoping the furnace would somehow fix itself. I was reluctant to take a day off from work to meet a service technician. I didn’t want to spend the money on repair. I procrastinated until the furnace eventually quit altogether. When the technician took the system apart, he pointed out the buildup of dust clogging all of the components. He explained that the debris within the inner workings had blocked airflow and restricted the moving parts, causing the furnace to work harder. The system had eventually overheated. I expected the technician to clean the equipment and maybe replace a few parts. I assumed the repair would be fairly expensive but completed quickly. Instead, he informed me that there was a crack in the heat exchanger. The crack was so small that I couldn’t even see it. Because the heat exchanger is the component that prevents carbon monoxide and other combustion byproducts from entering the breathing air, it’s super important. It also costs more to replace than buying a whole new furnace.