Door Bottom Brush draught excluder. COLOUR: WHITE Dimensions: Brush strip length 838mm wide, thickness 6mm, brush length 25mm Advantages of Draught Proofing - As a rough guide, fitting draught proofing can reduce your heating bill by £8-10/year per window or door. Your house or commercial property will loose heat during cold weather partly due to poor thermal insulation, but also due to air infiltration or the permeability of the building. Infiltration or permeability is measured in meters cubed per hour per square meter of floor area. A typical building built 1900 to 1990 will loose around 20-30 meter cubed of air per hour per square meter of floor area due to poor draught proofing. This is due to natural leakage through the fabric of the building, but largely through gaps around windows and doors. Good use of draft proofing could reduce your air permeability to around 10-15 meters cubed per hour which is a good low cost way of reducing you heating bills.