design for a sustainable future
Replacing a Victorian window
There are around 26 million homes in the UK and it is estimated that at least 86% of this building stock will still be in use by 2050. More than 80% of all houses in the UK were built before 1980. Housing is responsible for nearly one third of the UK's CO2 emissions. Original Victorian windows cause massive heat loss. Are there appropriate solutions for replacement?
Large parts of London and other cities were built in the second half of the 19th century in the Victorian style. During this period property development and building works on scale hitherto unknown were undertaken. Housing was mass produced for the first time with a sample book at hand to pick and choose from.
Most of the windows were sash windows made from wood with their very distinctive design and style. They were very well integrated into the building fabric, the brick walls and the overall cityscape. Most of us love sash windows for their style, look and feel.
These windows have however one big down side - they are highly energy inefficient, often draughty and make it difficult and costly to keep houses warm. This inefficiency obviously leads to high CO2 emissions, which should be avoided. The thermal conductance of the shell of a building is measured by its u-value. (The lower the u-value, the higher the performance.) A standard Victorian brick wall has a u-value of 2.0, a Victorian sash window has a u-value of 5.0 whereas windows built to a modern Passivhaus standard have u-values of 0.5 to 0.8.
Any replacement window should obviously be sympathetic to the existing Victorian structure. All Victorian windows were made out of wood and their frames were very well integrated into the walls with only about 1 to 2 inches visible from the outside. All mullions and transoms were thin and light in structure.
The window in our picture fulfils these criteria: It is made out of wood and perfectly integrates into the Victorian building structure. It is built according to the latest technical standards and requirements. It has a u-value of 1.1, shuts tight to retain the heat inside and to keep the noise of the city outside. Security locks are built in and the glass is laminated for safety and protection.
For a broad overview and advice o energy efficiency in buildings please see www.energysavingtrust.org.uk .
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