Just wondering if it is ok to run speaker wire between the housing of the heater vent and the floor? Will it cause any disturbances in signal or affect the integrity of the wire?
Hmmmm...if you're running the wire inside the walls or under the flooring in some way you 'might' have to comply with building codes. Usually that requires that you use wire that's fire rate and it'll say something like CL2/CL3. The exterior of that is a bit more durable than PVC and won't be as prone to decomposition.