After long search we finely got to a final point for window covers on our 2013 Sprinter Voila.
I split this summary into two groups:
1. Cab windshield, driver side window, passenger side window and a sliding door window
2. Driver side two rear windows, passenger side rear window, rear door windows
Re 2. This was a saga. We started with aluminized bubble pack attached with Velcro. We used it once; rolls of these cover were too bulky for storage.
We purchased external windshield cover with insect screens for driver and passenger windows, works great but it takes some time to deploy. We still used if we camp for extended period of time.
We made cab windows and windshield cover from the same colorful fabric used for curtains which was barely OK, cumbersome to deploy, easy to store, limiting cab doors access to the van. This cover was attached to Velcro straps located around the cab ceiling.
So, we purchased windshield, driver and passenger side windows, sliding door window and MaxxAir fan covers from the XPLR outfitters. With the exception of windshield all other covers use magnetic attachment. We will store these covers in the rear overhead cabinet and strapped behind the sofa in an unused space.
Re 2. I used overhead cabinet aluminum 80/20 frames as curtain guides which works perfectly. We are bored with seventies psychedelic colors and decided to change. We purchase a roll of fabric (gray #3) from XPLR matching well MB trim color and Mercury Grey HDPE color cabinetry. We also purchased curtain liner white insulated blackout fabric to replace our colorful curtains utilizing 80/20 sliders of my design. Replacing all curtains will become this winter DIY project or we find someone to sew the curtains.
During my search I Found quite few folks advertising their covers insulating qualities by incorporating reflective bubble foil in between other fabrics, well, heat transfer by radiation works only if reflective layer is exposed not covered by another fabric. It is a common mistake among camper vans builders.
https://www.eurocampers.com/2007--2...creens-choose-white-grey-or-beige_p_2345.html
https://www.joann.com/p/eclipse-white-insulated-blackout-fabric/18449827.html
https://www.xplroutfitters.com/