My husband has been using Stewart Heating Plumbing Air Conditioning for years to take care of his rent houses, and my daughter uses them, too. So, when I wanted to get my furnace checked out, I called them out. The service tech looked at my system, and he said that there was no cracking, but that there was a significant buildup of dirt to the point that it was a safety issue. He said that the furnace simply needed to be replaced. Since I am a senior citizen, he wrote all this down so that my family could review it with me. They agreed that the furnace needed to be replaced, and so a new furnace was installed. The service tech was very professional, and I have been very pleased with Stewart Heating Plumbing Air Conditioning's services!