Over the years I have noticed many rv's going down the road with a foil looking stuff in their over the cab window. It turns out the product used is called refectix. It's a bubble wrap with a reflective foil on both sides. It works great at reflecting heat from windows., and keeping the RV a little cooler.
Here's the warning. This year went took a trip in our motorhome to southern Utah and Arizona. We knew it would be hot so I thought I would give the Reflectix a try. When we got home, I was detailing the rig and I noticed that the sealant in the window over the cab was oozing out. In some places the sealant, which is called black Butal, had melted and oozed out about an inch or so. I decided to remove the window and then test it for leaks. It leaked a lot! You could actually see gaps in the butal where it had oozed out. I did some research and found many statements by other RV owners who had problems with this product. It seems that the temps get excessive when the Reflectix is on the inside of the window, hot enough to even break a window. Just to be clear, black Butal is the sealant between the glass and the window frame. Grey Butal is used to make a seal between the frame and the fiberglass wall. I have replaced the sealant and now have a water tight window. I won't be using that product any more.
2009 Sunseeker 2860DS
Bulldog keyless entry
Airlift remote compressor system
Ultragauge EM Plus OBDII monitor