Buildings lose heat in two ways: through the roof, walls, floor and windows, and they lose it through holes.
Fresh air is important, but ventilation and draughts are different things!
10% or more of heat loss in a building can be through draughts: window frames, holes left by builders (around pipes or cables), around outside doors, gaps in the floorboards etc. An open, unused chimney can account for another 40% of heat loss.
Draught-busting is a quick and easy fix, and means that you can turn your thermostat down without feeling colder.
Read about it before you take the plunge – click here for DIY Draught Proofing ideas.
And here for information on draught proofing and ventilation.