Gary -
One other tip: I found a thick square pillow that fits the fan opening. That, and a bungee cord to keep it in place, helps keep out the cold during winter months.
FWIW & HTH. . . 
RJ
I gave up the pillow and went to a velcro-type attachment on insulated reflective material. It is easier to store whilst not in use for us full-times.
"winter months"? What are those?
