[Motor31]

The R values were set based on a wall with no holes poked in it for doors or windows. Once you break the insulation for those items the entire R value drops. Fiberglass always drops as well even in a fixed location Park model much less one that is dragged down bumpy roads.

We have dual pane windows. I still feel cold seeping through the one next to my chair and I recently pulled and resealed that one. That 1/4" air gap is not much insulation at all. It is slightly more than a single pane but not by much. Heat transfers through as well from solar heating and radiating into the unit. We had to foil the big back window when the rig had that end pointed towards the west while in AZ. in spring and summer. The curtains stay down when we do not want the sun in to help heat the rig or they are not in shade like from the awning.

If the walls are about 1/3 windows I'd consider the R value to be down by at least the same amount over all.

Another thing to consider is the slide out floors are not insulated other than by the plywood they are made with from what I have seen in my rig.