reflextics - well the shiny bubble wrap type stuff

[Hepcat]

Reflectix serves two functions... as said above, it can reflect heat and sunshine with its shiny surface and it's air-bubbles between the two layers of material act as a thermal barrier. SO, if you use it when the van is hot and you cover it, it loses its reflecting ability, AND it acts as great insulation to keep the heat in the van. That's probably not a bad thing in the winter, but in the summer it's not doing the job you want it to do if you cover it.