I have a small fixed skylight and figure that during winter it's no problem to block the tunnel at ceiling level as suggested by an answer to a similar diy.stackechange question. (The only difference is that I like the light the skylight provides, so rather than rigid foam I am thinking of using clear multiwall polycarbonate panels that provide an R factor of 2 or more.)
The skylight is over a stairwell and difficult to get to so I'm thinking about leaving it in place year round. What would happen if I were to leave this in place during the warm months? It's dry and hot here in central CA in the summer, but would I still be at risk for condensation or mold on the drywall tunnel?