What Is Secondary Glazing and What Are Its Advantages
This guidance provides valuable advice on the principles, disadvantages, substances and procedures for updating the thermal performance of windows with the inclusion of secondary glazing.
Windows make a significant contribution towards the nature of historic buildings and every attempt should be made to keep them. They could additionally show a great deal about the history of a construction; shifting architectural taste and fashion, social hierarchy, building economics, craft abilities and industrial progress.
Older windows may well be draughty as eventually they distort as joints become distressed. Although sufficient venting is crucial in older buildings extreme air leakage through windows squanders heat and is depressed for occupants.
Carefully planned and installed secondary glazing enables the initial windows to be maintained unchanged, and where necessary fixed, whilst reducing air flows and conducted heat decreases. Thus there isn’t a damage to historic material as good as in most cases the setup is readily reversible.
Recent study has shown heat losses by conduction and radiation through a window typically talking can be decreased by over 60% by using secondary glazing with a low emissivity (low-E) tough coating facing the outside. The research has also demonstrated that additional savings can be made if the secondary glazing utilises insulating frameworks or uses double or vacuum glazed units.
Along with raising the thermal performance of windows, secondary glazing can have several added extra advantages including being exceptionally successful at restricting sound transmission.
For listed properties it is necessary to refer to the Conservation Officer at the local planning authority for guidance ahead of the installation of secondary glazing. Listed Building Mandate may be required in some situations.
Just what is secondary glazing?
Secondary glazing is nothing new. In the 19th century some buildings were built with internal secondary glazing designed as part of the initial layout. Frequently another double hung sash window or solid panels with counterbalancing weights were fitted in the space below the window. Their function was to decrease the heat loss and provide some measure of sound insulation to the window aperture.
Secondary glazing is a completely separate window system applied to the room side of pre-existing windows. The first windows stay in place and in their original unaltered form.
Secondary glazing can be found as open-capable, removable or fixed components. The open-capable panels can be either casements or sliding sashes. These kinds allow accessibility to the outside window for cleaning and the opening of both the secondary glazing and outside windows for fresh air. New secondary glazing was created to be detached in warmer months when its thermal extra advantages aren’t required.
Using glazed outside protection for windows using either glass or plastic sheet is known as ‘storm glazing’ rather than merely secondary glazing. Doing this can frequently be used to shield stained glass in churches. Using this kind of system, it’s crucial that you comprehend the potential conditions this creates in the airspace between the present glazing and the additional outside glazing where venting will be needed. Report should also be taken of the environmental conditions inside the construction before designing the setup.
One alternative would be to install storm glazing in winter and remove it in the summertime.
Fixing existing window openings
Recognized hardwood and metal windows can more often than not be restored, even when in relatively inferior state and as a rule at significantly less cost than complete replacement. The strong lumber used before to make windows was of a high quality and quite durable.
Tons of Georgian and Victorian windows are still in place now whilst modern windows can need replacing after just 20 years. Re-building windows is the best method of keeping the visual nature and architectural importance of a building’s elevation and can add to its worth.
Before beginning any updating work including draught-stripping or the adding of secondary glazing, assess what repairs are needed to make the windows completely operational. Windows deteriorate over time so standard renovation, cleaning procedures and painting is always an excellent investment.
For listed buildings, the complete replacement of a window will probably entail Listed Building Consent.
Secondary glazing or double glazing?
Double glazed windows usually have sealed glazing units with 2 panes of glass broken up by an air gap (usually of 12-18 millimetre) that improves thermal insulating material, especially if the glass is coated and the air gap is filled with an inert gas. It’s a significant development that’s generated substantial energy cost savings and reductions in carbon dioxide emissions, especially in new buildings. The Building Regulations make double glazing pretty much obligatory in new building.
Frequently the replacement of present windows using double glazed units can in many scenarios lead to a change in look, especially the smoothness of new glass and the demand for broader hardwood segments and glazing bars.
In historic buildings, there should be a strong taste for renovation as an alternative to replacing as the utilization of double glazing will necessarily bring about a reduction of conventional material. Adding secondary glazing would normally be the favoured option.
The advantages of double glazing over alternate approaches of window enhancement in many cases are overestimated. Much of the relaxation and energy performance advantages of new double glazing come from the decrease in draughts which will result from well-fitted window frames with built-in draught-proofing. These additional benefits are also accessible through repair and draught-proofing of the present windows, or from fitted secondary glazing. With standard progress in the efficacy of secondary glazing it may even be potential for the operation of secondary glazed windows to surpass that of new double glazing.
When it comes to sound removal, double glazed units are not any better than single glazed units; and can be to some degree subordinate for traffic sound. The significant principles for noise reduction are that the windows are nicely suited and draught-proofed. Secondary glazing, with its considerably broader gap between the window panes, is a better sound insulator. Wooden shutters and heavy drapes may also make remarkable progress to sound insulation.