The final step in drying-in house is install Windows an exterior Doors. A single pane of glass provides very little insulation (R-value) of less than 1. Install windows with 2 or more glass panels doubles the insulation or R-value. Low-e (low-emissivity) provides even greater insulating properties. the best approach to window or Door is to follow the manufacturer's recommended procedure, and fasteners (also check locals codes).Before the installation the rough opening must be made weather resistant installing the proper flashing.