Call me crazy, but would this work?
It just occurred to me while checking out this
SolarSheet product, what if you built a storm window that was made of thick, medium-dark tinted glass (not opaque, though, otherwise it would get claustrophobic), then left a small gap between the head and sill of a south-facing window (or installed a small one-way vent top and bottom)
Would that generate enough heat to make for a cheap temporary trombe wall that someone could install in the winter to provide supplementary heat and remove in the summer? Would that be superior in performance to using just a regular storm window?
I guess I'm wondering if the heat output and air flow from the sun beating down on the airspace would compensate for the heat loss from not having a traditional storm window.
If this would work, it could be the ideal solution for a one-size fits all passive solar retrofit product that isn't incredibly ugly like most
cheap solutions.