We are outside Calgary at the moment. Last night the temps really dipped to 6C, so furnace came on several times. At 6AM, it clicked on and there was a terrible loud noise. I instantly remembered Ray's video about the mouse in the furnace fan. Re watched it and we felt we had same issue. Took furnace apart and sure enough!
Your video helped so we didnt waste time trying to figure out what the problem was. We zeroed right in on it. Thanks Ray!