In this impressive 1860's townhouse in Twickenham, SashWise fully restored the original sash boxes and fitted new Accoya double glazed sashes within them. The before and after thermal images clear show the improvement in reducing heat loss.
In October 2025, we upgraded the timber sash windows to this magnificent townhouse in Twickenham.
The existing sash boxes were carefully stripped back, fully restored, and new Accoya sills were fitted where required.
We manufactured new Accoya timber double glazed sashes matching the design and proportions of the original windows, paying particular attention to replicate the arch of the first floor windows.
The before and after thermal images clearly depict the noticeable improvement in thermal efficiency of the new windows. The yellow/orange shading of the windows in the before image signifies the high level of heat loss through the original single panes of glass.
In contrast the darker pink/purple shading of the windows in the thermal image taken after the new windows were installed, provides clear evidence of the reduction in heat loss and improved energy efficiency provided by the new double glazed sashes.
Amazing improvement in the appearance of our Victorian house, the new windows look incredible and wonderful quality. The sash window replacement was carried out over 5-6 days with minimal disruption, the fitters were so polite and diligent and they left the house so clean after the work. We have already noticed the improved draught-proofing and external noise reduction, I am only sorry we waited so long for the original windows to be replaced. Great customer service and at a really competitive price. We absolutely recommend SashWise as a company for quality window work and their outstanding customer interaction.
