Foam covers for basement windows?

I was thinking of adding some foam covers to block my basement windows, reason is this year is my first with my pocono and it doesnt make as much radiant heat as my old markIII did as it has a duct top routed to the main floor. so i was feeling around down there (take that any way you like) and theres def some cold air from the windows, think making panels from that house insulating foam would help? or am i just trapping moisture on the window frame and making more trouble later on?

Get som bubble wrap and cut some sections out as big as the panes. Spray some water on the window and they will stick to it.

My dad made covers for the cellar windows out of 2" blue foam insulation, he said it raised the ambient basement temperature a few degrees.

That's what I use, the 2" blue--cut it carefully & you have a nice pressure fit--& yes, it makes a difference.