Slightly different situation for me.
My “greenhouse” is a 4 by 16 ft structure on my south wall.
With low mass.
It yields heat an hour after the sun comes up- no matter the outside temp. I send that into the house.
BTW, I used “4 year” film - that’s lasted 10 years and is just now starting to show degradation!
https://www.growerssolution.com/PROD/4-year-6-mil-clear-greenhouse-film/G4Y6MGF
Very nice! Great idea.
My very first ‘greenhouse’ was at my old farm 30+ years ago. I found pallets and glass sliding door panels in the abandoned barn. I put the pallets on the ground and leaned the glass doors over them at an angle, against the south-facing pole shed wall.
And I pretty much COOKED anything I put in there, LOL! I though having both ends open would be enough airflow and a place for the heat to escape but, NOPE! Rookie mistake. ;)