Winter Curtains?

We have not experienced cold temps mentioned by other, but we have made modifications to our Tiger RV. We would add insulation to the outside wall inside of the of each of the cabinets & inside the cabinet below the sink where possible. We also added insulation along the outside area of the couch and back area around the generator space. We also added insulation around the generator itself to help quite it and insulate it. The alum bubble insulation is available at most hardware stores. Probably the best idea was one Holly came up with to help with cooling & heating problems. She stitched up a replacement curtain to go between the coach & the cab area. It consist of fabric of your choice on both sides of a section space blanket, all stitched around the perimeter of the fabric creating an insulating blanket. This blanket works in summer to keep the heat from the cab out and in the winter to keep the heat in the couch area. It could be sized to go from floor to ceiling if needed. This idea could be used to insulate any outside window or Fantastic fan outlet. We keep a blanket on top of the dog crate.