Sash windows by nature of their design are draughty. Tolerances between each sash and the frame and beads equates to there being a hole in each window between four and eight square inches (depending upon window size).
This causes issues with increased heating costs, uncomfortable draughts and noise levels.
Draught proofing is the fitting of a brush pile draught excluder within these gaps. Brushes are fitted within the top, bottom and meeting rails of the sashes and seal against the frame. The parting beads between the sashes are replaced with either a plastic or wooden version which contains a further brush to seal the gaps between the beads and the sash. Finally, the internal staff bead is also replaced with one containing a brush.
This process can be carried out in a similar way on casement windows and exterior doors. A brush pile being inserted into the edge of the door or window to seal the gap between them and their frame. However, a limitation can be locks or hinges fitted into areas the pile needs to be inserted. At these points the pile may not be insertable so that a draught may continue through the gap where the lock or hinge is. However, this really is dependent on the thickness of the door or window being dealt with.