My home has separate heating and cooling systems. (The heating is done with radiators and the cooling is a conventional AC.) Does anybody happen to know if Nest works in this type of system?
You shouldn't, unless you can't run the wires to the same location for some reason.
What we have in our favor, though, is that the boiler is in the unfinished basement, the air handler is in the unfinished attic, and our electrician ran some pull string through a chaseway that connects the two. It may actually be possible to get both sets of wires to the same spot.