DIY Secondary Glazing Kits – Do They Work?

Secondary glazing is a good way to improve thermal insulation and reduce noise without the hassle and expense of fitting brand new windows. It’s a great option if your existing windows are in good condition and you like the design and don’t want to change it.

P erhaps you just need to improve energy efficiency or cut out noise or maybe you want to reduce condensation or improve security. Secondary glazing could provide the perfect solution.

What are the Options with Secondary Glazing?

One of the main differences with primary and secondary glazing is that, if you are quite handy and used to doing DIY, then you can fit secondary glazing yourself, not an option with primary glazing.

It’s easy to find DIY kits online or in your local builders’ merchants and there are three main types.

Insulating Film Secondary Glazing

This is the easier and cheaper of the different DIY options. All you do is stick a layer of transparent film over the glass of an existing window. This moisture-proofs the glass and creates an insulating air cushion which reduces any condensation and improves heat retention, although it won’t improve security or cut out external noise.

Film secondary glazing is not designed to be permanent. So, you fit it in the winter and remove it in the spring and throw it away. It’s also fiddly to fit particularly if you have any features on the window like lots of glazing bars or leaded lights.

Plastic or Acrylic Panel Secondary Glazing

This type of DIY secondary glazing uses a plastic glazing panel which is secured by either self-adhesive or magnetic strips. There are also variations which require screwing the framework into place.

Plastic is a good insulator so the secondary unit gives you all the benefits of a traditional double-glazed window with draught-proofing, better noise and condensation reduction plus heat retention.

The drawbacks with this type of secondary glazing is that the cavity that is created between the two windows can become very hot in south facing rooms and effectively overheat. Eventually, this can damage the strips holding the secondary glazing in place. They can also be tricky to fit unless you are used to home DIY projects.

Horizontal or Hinged Secondary Glazing

Hinged secondary glazing allows access to the main window so you can open both when you want airflow. However, there are two sets of handles so some people find this unattractive. Horizontal sliding secondary glazing is often used with casement windows and allows full access to the main window for cleaning or opening.

Why DIY Secondary Glazing Kits are not Always the Best Option

One of the most frequent mantras our fitters and installers hear on a regular basis is, “it seemed like a good idea at the time!” Secondary glazing is a great idea for some homes but getting a professional finish that works and doesn’t ruin the look of your existing windows is not as easy as you think.

The concept of secondary glazing is tried and tested. If your current windows are the design you want and in good condition then it seems pointless to renew them. Secondary glazing adds in the features that might be lacking such as noise reduction, better security and improved thermal regulation. However, despite the assurances on the kit that its easy for a homeowner to fit themselves, it really isn’t that straightforward. If you don’t do a good job, then the aesthetic will be poor and you won’t achieve the improved performance that spurred you on to start the process in the first place. Here are some of the main challenges a keen DIY enthusiast might encounter with DIY secondary glazing kits: –

  • You don’t have the style of windows that work with film so have to use plastic or acrylic secondary panel glazing
  • Plastic panels can become ‘foggy’ and less transparent over time
  • Poor quality or lower end DIY secondary glazing doesn’t always have a pleasing aesthetic
  • Secondary glazing just doesn’t have the thermal performance of good quality primary glazing

Secondary glazing has lots of advantages, for homeowners who don’t want to change or replace their existing windows. It’s suitable for virtually any type of home where the existing windows are not energy efficient, especially those with single glazing. It’s a fraction of the cost of replacement windows and it can get around  tricky issues with planning and listing officers with period homes or houses in a conservation area. It can sometimes be hard to upgrade the current windows without installing a like-for-like expensive timber replacement to avoid infringing the regulations.

Secondary glazing creates a gap between two windows that provides insulation which slows down thermal transfer. Because the air in the space is unable to circulate freely, the convection is also slowed down, further reducing heat transfer. Secondary glazing doesn’t usually need planning permission either. However, its tricky to get a quality result that delivers the right performance if you fit secondary glazing yourself. It’s better to save time and money and consult expert window installers.

We install secondary glazing in all types of properties as well as repair, restore and manufacture new timber windows. Our window solutions are suitable for all ages and styles of home, from traditional and quirky to modern and contemporary. We offer an endless choice of shapes, sizes, and paint colours with the ultimate blend of modern materials blended with old-fashioned craftsmanship, fitting windows that offer everything for the 21st-century.

Contact us here to learn more about our secondary glazing, new window replacements and our repair and restoration services.