I have two of them and they work great.Don't know what you could be doing wrong.the thing i found with mine is you have to do exactly what the instructions said.
Cold you kidn,Today it was 80 out.And yes i screwed the checker plate to the wall.The insulation works great warm in the winter & cool in the summer months
Those cars are owned by my buddy and his brother. I've been tuning & fabricating on these two since day one.As for the shop i built everything my self to save money,I'm far from loaded.