I have been thinking for a long time about building a Passive Solar Window Heater similar to this:
I live in northern - North America which during the winter ranges from 30°F during the day to 0°F at night (on average).
I am note sure if it will help but it seems like an easy and inexpensive project I can do but the thing holding me back is this; what happens at night? How much heat will I loose out this "open window" during the 16 hours the sun is not shinning on it?
I was wondering if someone else with similar conditions could weight in on how it has worked for them. The last thing I want to do is take it out every night and back in every morning. I know that won't last long. The other option I thought of was a way to close/seal/insulate the opening at night. That twice a day task might be possible.