We cut some 1? styrofoam to fit the vent openings, then used spray adhesive to attach aluminum foil to one side. The foil side faces up and keeps out the light as well as provides some insulation. Additionally, I was concerned about the thin plastic skylights themselves holding up in the Florida sun, so I made some covers for them as well. I screwed some metal roofing cut to size to a couple of lengths of 4? pvc. The pipes keep the metal situated just above the plastic and protect the skylight from the sun, as well as the occasional broken branch or pine cone. I remove them when we?re traveling, but when we camp in S Fla during the summer, I bring them along and put them in place once we get set up. Plenty of light still gets in, but the a/c doesn?t have to work as hard.