DIY Furnace Install

[Jon Bon]

Anyone done this?

What is the one thing you wished you knew before hand?

My DIY chops are pretty solid, I have worked with gas pipe before and it was not a big deal. Really what I am worried about is lining up the Return/Supply air to the new furnace.  I am aware of MMM article on this. I will probably do a HE model so I can knock down all the chimneys some day.

Questions:
1. Do you almost always have to fashion a custom sheet metal return?
2. Do you try to find a furnace in the same dimensions as your old one to minimize #1?
3. Any measuring/adjustments that need to be done after it is installed?
4. How to work with the cooling coil above?
5. Any general observations you could share with me.

I plan on having my trusty HVAC guy look over everything after I am finished. I have about 2-4 of these to do at my own leisure so I feel like it would be a substantial cost savings.

[affordablehousing]

I'm looking at this same activity, replacing an old gravity furnace, asbestos ducts and all with an alpine air model and flex ducting. I agree the return air attachment agitates me. Then again, my return air ducting as it is is so rusted it's like swiss cheese, and things work, so what's the worst if it leaks a bit, lowered efficiency? I'm planning on doing my best and using lots of foil tape and goop.