Sash windows are not so bad after all

New scientific evidence is available from the English Heritage to counteract some of the misconceptions about the energy efficiency of original sash windows. Recent findings have shown that with simple repairs and basic improvements significant reductions of draughts and heat loss can easily be achieved.

Key findings have shown that Simple repairs to mend cracks and eliminate gaps can significantly reduce the amount of air infiltration or draughts by around one third. Also, adding draught proofing can reduce air infiltration by 86%. More elaborate measures reduce heat loss even more and can improve windows to meet modern Building Regulations, which target a U value for windows of 2 or below.

Dr Simon Thurley, Chief Executive of English Heritage, said: “It is very encouraging to see that more buildings are being refurbished to meet modern energy requirements, but all too often a drastic and insensitive approach has led to the degradation of our streetscapes . Many original timber sash windows have lasted more than two hundred years and are capable of lasting another century. This piece of research provides the hard evidence that shows how easy it is to upgrade them and supports our call for their retention.”


English Heritage