Dear Slashdot, I have a 1 and a 3 and I need add them and make 5. How can I add them together to get 5? Please don't tell me 1+3=4. I need it to be 5.
There's zero fucking reason to put an HTPC in a crawl space. Get a small machine and stick it by/behind the TV. Minimal power / video / network cabling, minimal worry of dust / moisture / temperature, minimal issues with connecting to a keyboard / mouse / remote, minimal issues with access when it needs to be physically powered on off (and it will), minimal cost, etc. They even have cases small enough that you can mount them on the TV's VESA mounting holes.
Oh, I can think of a reason: One or both members of the household has a strong sense of aesthetics and do not want anything resembling a computer in the living room.
In ran into this once with the girlfriend of the guy who owned the house I was living in. I was arranging speakers next to a big CRT TV. I noticed that the speakers interfered with the CRT, causing quite noticeable color distortion strong near the side and fading toward the center. I suggested moving the speakers out a foot as I found that this was enough to cure the distortion.
Her: "No, it looks better the other way"
Me: "But it doesn't work well"
Her: "keep the speakers close"
I gave up. Not my house and she watched the TV much more than I did.
The current current situation is probably considered acceptable only because the machine than drives it is a laptop and it gets packed away when not in use.