The greatest potential for heat loss is through glazed windows and doors, fortunately modern triple glazed units can now achieve a transmittance or ‘U’ value as low as 0.7 W/m2K which is far more effective than a traditional single glazed unit with a ‘U’ value of around 4.5 W/m2K. Both triple and double glazed units of the highest rating will be utilized in the new house.
Double glazed windows will be used in the south facing elevation as the area of glazing is nearly half that of the north elevation, this will take advantage of the extra sunlight a south facing window receives and will help to balance the overall solar gain. The larger north facing glazed units afford the best view from the property but will also suffer the most from wind chill, because of this, all windows and doors facing north will be triple glazed. Both the double and triple glazed units will be Argon filled and manufactured with low emissivity glazing. The glass within low 'E' glazed units has special reflective coatings which reflect heat back into the room, the coating has very little impact on the transparency of the window unless tinted by design, a very slight tint may be visible from outside under certain conditions.