Barnsbury Joinery Co.

London Office 

Ripplevale Grove, 

Islington, London. 




Barnsbury Joinery Co.

Hertfordshire Office 

Blacksmiths Lane, 

St Albans. 

AL3 4SQ 

Barnsbury Joinery Co. © 2019 London's Leading Bespoke Joinery Company. All rights reserved.

Environmental Benefits of Original Timber Sash Windows 


With carbon emissions being on the rise, the ever-increasing need to be environmentally friendly also applies to period properties, many of which have timber sash windows with single-glazing. If you are thinking about replacing or improving your traditional timber sash windows, now could be the time, as environmental concerns are growing across the UK. 


The Department of Energy and Climate Change stated that ‘in 2016, UK net emissions of carbon dioxide were provisionally estimated to be 479.1 million tonnes (Mt) […] increasing on the previous year by 4.5%, (DECC, 2013). The typical traditional home will lose about 10% of its heat through windows and 15% through draughts.


When measuring thermal efficiency, windows are measured by their “U-Value”, with 'single-glazed timber-framed windows having a U-Value as low as 5.5, with double-glazed windows having a rating of 2, over half the loss. Did you know that ‘Replacing your old timber windows with new double-glazed timber windows can reduce heat loss by half, save around £110 a year on fuel bills, and around 720kg CO2 a year.


The Barnsbury Joinery Co specialises in installing double-glazed Slimlite units. These have a 7mm perimeter seal depth, and can be glazed into most single glazed period windows, giving a U-value of only 1.9, meaning your period timber sash windows can now be A-grade energy efficient. When thinking about updating period properties, owners often find replacement of windows the easiest step to reduce heat loss, thus CO2 emissions, popular because loose-fitting frames with cold glass are often a very telling reminder of heating losses.


In addition to the energy efficient double-glazed Slimlite Units, the Barnsbury Joinery Co has also perfected a process called E-Seal, a sensitive process of introducing delicate fibre and pressure seals into the working areas of sliding sash windows. These gaps, if left unfilled, can cause dirt and dust ingress, draughts and heat loss, but with E-Seal, sash windows can be made more environmentally friendly without changing the appearance of the window. Because the process is sensitive and discrete, conservation approval is easy to obtain and many conservation groups welcome this product as an alternative to uPVC windows.


We should all be doing our part for the environment, but if you feel you can’t contribute because of restrictions through conservation regulations, or even budget, you can rest assured that the  will help you find an environmentally-friendly and economical solution in making your period property more energy efficient.

To save time at Barnsbury Joinery we have implemented an online quote request system. Once we receive your request we will endeavor to contact you within 24 hours. If you require assistance or would like to discuss your requirements, please do not hesitate to contact us directly on 0207-1646305 and we will be happy to help you.


At Barnsbury Joinery Co we service all of London and Hertfordshire. Including Islington, Hackney, Hampstead, Primrose Hill, Camden, Stoke Newington, Clapham, Angel, Canonbury, De Beauvoir Town and Clerkenwell. Please call us now to find out if we work in your local area.