To understand the true benefits of secondary glazing, we must first understand what it is. Double glaze windows make a home energy efficient. It saves homeowners money on their cooling and heating bills. They also cut down on CO2 emissions by up to 740Kg a year. Secondary glazing usually involves the installation of a second window in the interior next to the existing window. This helps to approximate double glazing in principle and helps cut your CO2 emissions by up to half a tonne per year.
The second panel creates a still air space between itself and the existing window which significantly reduces the transfer of heat from outside to inside during summer, or inside to outside during winter. The second window is usually made to match the appearance of the existing window while the original window remains untouched. They are intended to be unobtrusive, can be opened or fixed, and can be installed quickly without the need for redecoration.
There are several common methods of secondary glazing. Usually a glass panel that is encapsulated in a frame and attached to the inside of the window unit or a frame added to the window reveal. Sometimes an acrylic panel is used instead of glass to make it lighter. There is also a method of using heat shrink plastic or cellophane attached using double-sided tape. This method cannot be removed for cleaning without destroying the components, and does not usually last more than one season.
It has the advantages of being more cost effective than replacement double glazing while providing similar performance and the disruption of construction work is also avoided. It is the ideal solution for Listed Buildings, in Conservation Areas where replacing existing windows is not a practical option, or in high rises with strict body corporate control. Internal secondary glazing can be a cost effective solution if the main window is essentially sound and in good condition and there is a desire to improve thermal and/or noise insulation.
There are many other benefits from having secondary glazing. If the gap between the secondary glazing and the original window pane is at least 40mm, the still air space between the two panes provides good insulation from exterior temperatures, therefore, reducing noise significantly as well as condensation. Specialist glass is especially effective against road, aircraft, rail noise or any type of noise. If a 6.38mm laminated glass is used, it gives you a 94% UV block while allowing natural light into the room without fading carpets and furnishings. Since secondary glazing can only be opened from the inside, it adds considerably to security of the dwelling. The use of toughened or laminated glass and additional locks will further increase window and door security.
There is very little air movement within the cavity between the two window panes, thereby, virtually eliminating the ingress of dust and cutting out any rattling of the primary window as well as draughts. Maintenance for secondary glazing is also minimal.
If double glazing is out of the question for one reason or another, then secondary glazing is the next best approach. You will still enjoy the true benefits of secondary glazing and although it may not be as effective as double glazing, it certainly is a lot cheaper and a hundred times better than using plastic bags.