This time of the year we often get calls saying our heat does not work! The furnace is on but no air is coming out. I ask them is the fan spinning? They say yes, but no air is coming out. I can hear it whistling but no air is coming out of the vents. I have to tell them, "Your crawl space is full of water and so are the ducts. Now we need to pump the water out of the crawl space and then replace all the ducts. (IF YOU POKE HOLES IN THESE DUCTS AND DRAIN THE WATER,) it is already to late. The bacteria can and most likely will grow. Often this water comes from bark dust piled up and letting water flow in through the crawlspace vents holes during heavy rain storms. Or a gutter gets plugged or broken making the water flow where it is not suppose to be. Don't let this happen to you. Take a walk around the house and check the vent heights around the house. See if you think water can get it. This can save you lots of time and money. If you do have this problem and you need furnace repair, duct repair, or a/c repair give is a call. We would be glad to help.