I noticed a mildew smell when we turned on our AC for the first time this year (currently very humid in KY). The smell is strongest in our bedroom; the furnace is located directly under our bedroom in the crawl space. When my husband and I went to crawl space to investigate, there was some water on the plastic barrier under furnace (horizontal mounting). Also, there looked like alot of condensation on furnace. Upon calling repairman, he found that the drip pan was broken thus leaking water instead of draining out through pipe. This is being repaired. He also recommended putting a fan in crawl space to circulate air or installing a dehumidifier. While we are getting all of these done, the mildew smell is causing some allergy problems. My concern is that mildew is growing in ductwork? How can we tell if it is and what do we do about it? Thanks.

I need to run 5 heat/airconditioning ducts (central air) for my basement. The main supply duct for the 1st floor is in the basement ceiling. It runs the entire length of the basement and I'm told by a couple of contractors that I can branch off it without any loss to the 1st floor. The problem is that they want $250 for each branch-off. i.e. cutting into the main supply, run flex pipe between joists and install the registers (?). I thought this was ridiculous. I need to run 5 of them and also want to have a return in the basement for which I'll cut into the 1st floor return that is also in the basement ceiling. I think I can handle it if I get the right instructions. My search on the web didn't turn up anything I can use. Can someone point me to a website/book I can use. I need pictures 'cause most of the times a picture can say it better than a full page of instruction. Is it ok if I branch off the individual vents going to the first floor? Will that take off too much away from the 1st floor? That would be easy for me provided it is ok to do. Thanks, Yankee