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Stay warmer and save money with our secondary glazing

Published on: 07/09/2022

Perspex and Polycarbonate Secondary Glazing

The UK's current cost of living crisis shows no signs of slowing. Millions of households continue to grapple with rising prices as interest rates increase and inflation soars. The situation is set to deteriorate further as autumn advances and the weather turns colder. Energy prices – already at an all-time high – are predicted to carry on rising. Future energy price cap forecasts suggest that bills will continue to skyrocket for the foreseeable future. So it’s safe to say that exploring new ways to become more energy-efficient is likely to become a key priority for most UK households before winter begins to bite.

Small changes can make a big difference to your energy bills. Most of us know, for example, that we should be unplugging unnecessary devices, eschewing standby mode, and even avoiding overfilling the kettle. Effective heat retention strategies, however, are even more important, as they'll help to keep you warm as well as reducing your energy expenditure. Installing secondary glazing is fast becoming a popular solution.

What is secondary glazing?

Secondary glazing involves installing another layer of material to create an extra internal window on the inside of an existing primary window. While glass can be used for secondary glazing, acrylic and polycarbonate offer a variety of advantages over glass, in terms of cost, functionality and safety.

Unlike double glazing, which involves fitting completely new units (with all the associated expense and disruption), fitting secondary glazing is a fast and simple DIY process. You simply attach the panels of acrylic or polycarbonate to your existing windows or window frames or using magnetic adhesive tape. It really is as quick and as easy as that!

The benefits of secondary glazing

First and foremost, secondary glazing is an easy and economical way to prevent heat loss from your home. It’s a fast, cost-effective way to help keep the heat in – and the cold out. In addition to improving heat retention, secondary glazing can also provide additional noise insulation and reduce condensation.

Estimates vary about how much of your home's heat is lost through its windows. But if your windows are old or poorly insulated, that figure could easily be as high as 40%. Installing secondary glazing is an excellent strategy for minimising heat loss, reducing draughts, and saving you significant amounts of money on your energy bills.

Another big advantage of our secondary glazing? Because it’s a temporary/seasonal solution to heat loss, it can easily be removed when the weather warms up again and it’s no longer needed.

Where can secondary glazing be installed?

Secondary glazing is immensely versatile and suitable for a wide variety of property types and locations. It can be particularly useful for period or listed buildings, which are subject to strict planning permission rules regarding changes to external primary windows.

Because secondary glazing is so cost-effective versus traditional double or triple glazing, it's a popular option for rental properties. We also see a lot of potential for secondary glazing within the public sector (for example schools and other educational establishments) as budgets become ever more squeezed.

Because it's so versatile, secondary glazing can be used on as many or as few windows as is needed. It's especially ideal for colder rooms with several outside walls. Garden rooms, extensions, annexes and external workshops can also benefit hugely from the extra heat retention that secondary glazing can achieve.

The best materials for secondary glazing

We supply acrylic secondary glazing and polycarbonate secondary glazing options. Both are cost-effective, offer excellent optical clarity, and are much stronger than their traditional glass counterparts, which means they much less prone to damage.

Acrylic sheets have up to 20 times the impact resistance of glass, and will not shatter into sharp shards. Polycarbonate is even stronger – and almost unbreakable. Both materials let the light through and keep the elements out. Polycarbonate retains slightly more heat than acrylic, although this is reflected in the comparative pricing.

The importance of values

When weighing up the benefits of glass versus acrylic or polycarbonate, it's important to be aware of K-, U- and R- values. K-value refers to the ability of a material to conduct heat. A low K-value is advantageous for insulating materials, as this means heat energy cannot easily pass through.

R-value indicates a material's ability to resist heat flow through a given thickness. Materials with higher R-values resist heat transfer well, and are more suitable for insulation purposes. The U-value measures the heat loss rate through a given thickness of a building roof, wall or floor. Generally speaking, the lower the U-value, the better the material in question is as a heat insulator.

This technical data can be very useful in terms of selecting the best materials for secondary glazing. For example, traditional single pane glass has an average K value of 0.96 whereas our Acrylic and Polycarbonate sheets have a K value between 0.19 and 0.21 which demonstrates why these materials provide superior insulation, in addition to being cheaper and easier to install and maintain.

Our acrylic and polycarbonate sheets have a variety of uses and are available in a range of different thicknesses and standard sizes, or we can cut them to your exact measurements. Cast acrylic is commonly used for glazingsignage and retail displays. Extruded acrylic is commonly used for lighting applicationsinterior decoration and screening. We also supply secondary glazing magnetic tape.

Related FAQs

Perspex is used in a vast variety of different ways - it's chemical properties, wide range of colours and finishes, availability and cost, make it the material of choice in applications and industries ranging from home repairs and general DIY through to construction, furniture design, retail displays, signage, lighting and interior design. In the home it can be used to replace broken greenhouse glass panels, as bathroom/kitchen splashbacks or even to replace broken picture frame glass. In commercial environments acrylic mirrors, acrylic block for retail displays and LED diffusers for lighting are commonly used. We stock and supply all of the Perspex product ranges, all of which we can provide cut to size and ready for use.

Acrylic is an extremely versatile material which provides great results when being laser cut or laser engraved. Both extruded and cast acrylic can be laser cut, however extruded acrylic can be left with a slight burr on the edge of the material after laser cutting whereas cast acrylic is left with an extremely smooth edge. Depending on the power of the laser tube it is possible to cut acrylic up to a thickness of 25mm whilst maintaining a square edge. Clear cast acrylic is normally favoured when producing awards and plaques because once engraved it turns a frosty white colour which creates a stunning finish. Certain colours do not react very well when laser cut because the pigment or dye in the acrylic reacts poorly to heat, however the edge discolouration can normally be reduced by modifying settings on the laser such as the cutting speed, the volume of air flow and the amount of power being used.