These are to keep cold air out and warm air in. They will also keep hot air out, but we seldom use them for that purpose. We move instead.
Reflictix is bubble wrap sandwiched between reflective foil.
Lowe's sells rolls of Reflectix.
Add about a quarter inch to each dimension, as the Reflectix tends to "shrink" some with UV exposure over time. Plus the extra material will keep them in place.
For cab windows, make paper patterns and cut using ordinary scissors. Then sew some cloth edging around the panels if you want them to be really classy. I took George's idea to spray paint the cab window covers white on the outside and beige on the inside to match the rig colors.
Not shown, Reflixtic windshield cover.
For extra warmth, put the LD foam cover on.
For the vents and skylight, just measure, add a 1/4 inch and cut.
Fan Vent with Reflixtic in Place
Note slit for knob
Fan Vent with LD Foam Cover over Reflixtic
Hint for fan vent, cut a slit for the open/close knob. For the other 14x14 vents, cut a slit for up/down handle. For the escape vent, I made them in two pieces with slits in both for the up/down handle.
We keep them in the windows in the upper bunk all the time, as we do not use that bed for sleeping.
Storage: I store both the Reflictix and LD supplied foam covers behind the curb side couch back. The cab window covers store in folded cab bed, which we do not use.
We find the combination of the Reflictix and foam covers really helps about 8,000 feet or when the outside temp drops below 40.