This typical Henderson Merlin Canopy in a softwood timber casing was replaced with a Novoferm ISO 45mm Wide Rib sectional door with Marantec Comfort 220 remote controlled operator. The window section above the door is PVC and double glazed, and the treated timber casing is also covered in PVC.
As shown in the picture, the door opens without swinging out of the garage, instead sliding down behind the frame leg and integrated rubber seal. This along with the seal fixed to the lower edge of the bottom panel effectively seals out all the drafts. Added to this is the 45mm of insulation between the two steel skins of the door.