This weekend I insulated the north facing wall of my greenhouse. It has two jalousie windows which are wonderful ventilation in the warmer months, but in the cold of winter they leak cold drafty air into the greenhouse, particularly when then frigid winds from the North are blowing. I managed to find 4' wide rolls of bubble wrap and with the use of duct tape( what could be more Canadian!)I covered the whole northern side. It may be my imagination, but it immediately seemed warmer inside.