Draughtproofing the doors, windows and other sources of excessive air leakage of a dwelling can be an effective and relatively inexpensive means of improving comfort and reducing heat loss by natural ventilation. The doors and windows considered in this digest are existing components not originally designed for draughtproofing. Products for general use on these components have to fill a wide range of gap sizes, be durable and retain the ease of opening and closing. This digest describes the requirements for such draughtstripping products, identifies kinds of products that are suitable for common types of component, and indicates situations where they can be cost effective. It also considers other sources of leakage and their treatment.