Double-glazed units, used in the doors and windows of all Hampton Conservatories, comprise an internal pane of 4mm clear planitherm toughened glass, a 12mm argon filled cavity and a 4mm clear, toughened glass, external pane with spacer bar. This, again, ensures outstanding thermal insulation. As with the roof units, our door and window spacer bars are normally black. However white and silver are available, as options, at no extra cost. All glass complies with current Building Control Regulations.