Pictured to the left is an image of a cracked heat exchanger in a natural gas furnace. A cracked heat exchanger allows for the exhaust of the burned fuel to leak out into your home while the unit is running, including carbon monoxide. Cracks in metal also widen when they are heated, making even the smallest crack a concern. This is one of the reasons why it is important for routine maintenance on your homes heating system this winter. We also recommend spending a little extra money and purchasing a nice carbon monoxide detector because after all it may save your life. As always contact us for all of your heating needs. (859) 429-2207. Serving All of Eastern Kentucky!