Personally, I use an exterior version similar to what members kbeefy & N147JK described = they keep a lot more heat outside. Once the sun hits & heats up any window it radiates inside...that heat doesn't magically escape, you'd have to vent it somehow, The exterior covers drastically reduce interior heat and only take a minute to apply...JMHO
quite a few Econoline covers available out there:
The Vanmade Gear Front Door Window Shade for Ford E-Series Econoline Vans (Pair) from Nomadic Supply Company® helps reduce your Ford E-Series Van interior temperature and protects the camper van interior from UV damage. Vanmade Gear hand-sews the world's best, ultra-premium quality camper van...
nomadicsupply.com
The Vanmade Gear Front Door Window Shade for Ford E-Series Econoline Vans (Pair) from Nomadic Supply Company® helps reduce your Ford E-Series Van interior temperature and protects the camper van interior from UV damage. Vanmade Gear hand-sews the world's best, ultra-premium quality camper van...
nomadicsupply.com
<br><br> <center><img src="https://turbifycdn.com/ty/cdn/yhst-16851555716622/sunsahde3.webp" alt="carpettextc8" alt="carpettextc8" border="0"> <img src="https://turbifycdn.com/ty/cdn/yhst-16851555716622/susnhades.webp" alt="carpettextc8" border="0"> <img...
www.high-end-motorsports.com
Maintain your privacy and keep the temperature regulated in the rear of your van with our rear window covers. The product is sold as a set, containing both a driver and passenger side window cover. They block out UV rays, insulate, and reflect radiant heat, keeping your van cooler in the summer...
vanmadegear.com
Ford Econoline Insulated Magnetic Driver and Passenger Window Covers by Overland Gear Guy. Ford E150, E250, E350 cab window covers for Ford camper van conversion, camper van accessories, Econoline van door window cover, magnetic window covers for Ford van, camper van front window covers. Van...
overlandgearguy.com
Etsy offers numerous options as well:
Some Threads that may provide insight:
Anyone using a wrap around windshield cover on an E350 they really like? I've tried a couple Amazon ones but they've been ill fitting and pretty light weight.
www.sportsmobileforum.com
Knowing I had surgery coming up, I made a big push to get a bunch of window cover orders completed and shipped in April. Whew! That was exhausting! I've since had surgery on my knee to replace a torn ACL and repair a torn meniscus. I'm itching to get back to making window covers for you all...
www.sportsmobileforum.com
A Google search would reveal more I'm sure.