You will ultimately decide for yourself one way or the other. We are all just giving our experiences and thoughts on the matter. <br /><br />For me I vote for insulation. Before I insulated my van I wound up in the emergency room from heat exhaustion and dehydration. At the time I was camping around the beach areas near Tampa/St. Pete area while working on a computer/network project. Since that ER visit I can't be in the sun or heat for more than an hour before my heart starts racing and the heat exhaustion starts all over again. I had to install an air conditioner and get a generator just to survive. That is a real problem since I work on outdoor WiFi systems most of the time. I have to take a break, get in my vehicle, run the air and cool off very often.<br /><br />Point is, if you are young and healthy you can sleep in your van in much hotter conditions. You can also ruin your health for the rest of your life by not taking care of your body. If it is too hot to sleep just roll up the windows, start your van and run the air for 30 minutes or so to get you and your van cool inside. Don't go to sleep with the van running unless you have a carbon monoxide detector.<br /><br />If we ever get to meet I would like for you to see the inside of my cargo van.<br /><br />VanGirl