A considerable amount of heat is lost though old single glazed windows. Replacing these windows with modern double gazed units is therefore an obvious choice. However all the original Burlingham properties have either leaded lights in steel casements or early Georgian style timber windows.
There are two options when considering how to improve the energy efficiency of your windows. In some cases the only option is to introduce secondary glazing and this is the preferred and less expensive option with listed buildings and in conservation areas. The advantage of secondary glazing is that it does not interfere with the original windows, improves sound insulation and the units may even be removable in the summer months.
Alternatively there are a number of specialist manufacturers who can provide replica double glazed versions of the leaded light windows in steel casements or the early Georgian style windows to be found in the original Burlingham properties. A list of these manufacturers can be found on www.abbotswood.org under Local Tradesmen/Manufacturers of Heritage Windows. Obviously the closer you can match the original windows and the window furniture the better. The decorative latch plates are a particularly attractive feature of the original windows. You would probably need to allow about £1000 per square metre for a good quality product.
Please be aware that Article 4 Directions apply to all the original properties, thereby removing all permitted development rights, which means that replacing any windows in an original property will normally require a full planning application.
Most of the original Burlingham houses on Abbotswood have steel casement windows with leaded lights. These windows are often prone to corrosion, particularly in the lower frame members. Rather than replace these corroded windows, it is possible to get them repaired. The repairs involved removing and dismantling the windows; sand blasting back to bear metal; replacing any badly corroded metal sections; polyester powder coating the completed window and re-glazing. The end product is as good as new. Residents are encouraged to retain these windows which are attractive original features, and often include very attractive handmade ironmongery and stays which are irreplaceable.
A local company which has carried out a number of window repairs on Abbotswood is Surrey Stained Glass Windows. Contact details for Surrey Stained Glass Windows, and other specialist in heritage style windows, can be found on www.abbotswood.org
Finally bear in mind that big improvements to the energy efficiency of a property can be achieved at relatively little expense by thoroughly draft proofing all external doors and windows and by sealing up any unused flues. Special inflatable balloons can be obtained for sealing up flues. This method has the advantage of being easily reversible.