Flash Content.
Draughts caused by the gaps between the floorboards, the letterbox, unused open chimneys, and ill-fitting windows and doors can account for 20% of heat loss. Fortunately, problems of this nature are easily resolved with simple, inexpensive forms of draught proofing.
Keep the warmth inside and reduce your heating bills by turning your home into a draught exclusion zone.
Next: Lagging