I picked up a Honeywell HE360A for our house with the intention of installing it myself. I went with the 360 for the fan due to the size of our house, vs using bypass which I don't think would have worked very well. I watched the video, opened the box, grabbed the template and went to find a place to mount it ... and there only spot that it might fit is too short.
Knowing not much about furnaces, it appears I have a high boy. There is a section of duct work that is 3" shorter than the template that uses an s-cleat joint to connect to another piece of duct work that has all the outgoing connections. In order to install the humidifier I would need to cut through this s-cleat joint. (Annoyingly, you can see a sheet that's been screwed in just above this joint where a humidifier used to be.)
Is that bad? Should I just go for it and use some putty/tape to ensure there's not a lot of leaking? I have plenty of room for a bypass humidifier, but with a 3,000+ sq.ft. house, I'm not sure that's going to cut it.
Edit - pictures! The unit itself, and the area w/ and w/o the template. The forum gave me an error that the files weren't images, even though they are, so here's a link to where they can be viewed: https://drive.google.com/folderview?id=0BxmfzSO89hU1MGRzczlQY2RNR2M&usp=sharing