While in theory that would work, what's going to cool your switch when the A/C isn't on?I just moved into a house that has about a dozen Cat5e cables with RJ45 terminations gathered into one spot in the attic, where it awaits a network switch to tie everything together. I put a remote temperature sensor up there and it hit 130 degrees with it being only 92 degrees outside. I had a fan blowing on it too. When the dog days of summer hit, it will only get worse. My network switch is rated at a max operating temp of 122 degrees.
I looked at extending the dozen Cat5e cables down through the ceiling into a nearby closet, but then I thought, "why suffer the signal loss of extending the cables with female-to-female couplers when there's a freakin' air conditioner and duct work within 3 feet of the switch location. I thought it might be either clever or ridiculously stupid to put the switch in a small enclosure and somehow tap into the existing AC duct work to cool the case. The case would only be about 12" wide x 8" deep x 3" high. Could a small hose be run from a nearby duct into the enclosure? How would I manage air flow within the enclosure?
I would extend the cables and put the switch in the conditioned space. There won't be any signal loss from doing that, the switch will be happy, and you will be happy when you can look at the LEDs on the switch when you are trying to figure out why something isn't working. Also, network switches tend to need to be reset on occasion, not easy to do if it's in the attic.