Suggestions to prevent door warping

[HannahHope]

I live in Wisconsin in a condo that is south facing. This spring, I had new exterior and storm doors installed. The exterior door is steel, but has vinyl trim around the window. The storm is full view with a glass insert for winter. Due to condo rules, the exterior door is dark brown and will get full sun in the winter. As there is no way to vent the storm door, the contractor said I will need to prop it open on sunny days to keep heat from building up and warping the vinyl around the window. My question is will any of those heat blocking, sun ray blocking films prevent the heat buildup or is proping it open be my best bet? Thank you.

 

[blup]

We’re on the other side of the pond so different weather conditions and rules, my guess is that a sun blocking film won’t make a jot of difference