Sanitize Beer Line

I have to brew in the garage and ferment in the basement. I am planning to use a 7 gal conical fermenter. My thought is to cool the wort upstairs, then siphon it downstairs with about 20' of 1/2" line to the fermenter.

Does this sound reasonable?

also
how would I sanitize this setup?

This is a fairly interesting idea. You would sanitize by putting sanitizer a bucket and siphoning that before the wort. The only thing I would worry about is the integrity of the 20' hose. It's been a long time since I took a fluids class, but there might be a risk of a cheap hose collapsing if there is too much vaccuum at the top. If you buy a reasonably thick hose, you would be fine, but the cheap stuff at Home Depot might not work.

Keep in mind that it's going to want to accelerate at 9.8m/s/s over the 8' (or thereabouts) vertical drop, so you might want a valve in line to limit the flow rate.

Mix up 2.5 gallons of Starsan and run it through the line. It will be sanitized by the time you start to siphon beer. Discard a few first ounces after the beer starts to flow through the end.

Clean the hose with warm water and PBW or BLC. Rinse with hot water using the same method.