Insulation Benefits of Secondary Glazing

Windows are wonderful for light and ventilation but vulnerable to heat loss, noise and condensation. They can be insulated to reduce the impact of these issues in many ways, of which Secondary Glazing is an important, effective and relatively inexpensive method, with straightforward and well-designed DIY systems being the least costly of all. To help you decide whether Secondary Glazing is right for your home, to learn more about energy saving, noise reduction and the financial implications of what you are considering, we have provided pages of information, explanation and costings, with informative videos and images to illustrate. Take a look at the summaries on this page, click through where relevant or access information via the drop-down menu. If there are any questions you have that we have not already answered, we are always ready to help and advise – just contact us, with images where they will show us what your windows are like so that we can think and comment appropriately.

Heat Retention with Magnetglaze Pro - Case Study

A room with old Crittall windows was insulated using Easyfix Magnetglaze Pro. For a 24 hour period during winter, temperatures were recorded to show the effectiveness of the insulation in retaining heat while temperatures fluctuated outside. Bluetooth thermometers were placed outside on the window sill, inside the room and in between the outer windows and the insulating panel, showing the excellent performance of the inexpensive Secondary Glazing.

Click through for more information from this efficiency test.

Secondary Glazing - an excellent insulator against heat loss

Do you have single glazed windows that lose heat fast in winter? These can be replaced with Double Glazed units, or kept with the addition of Secondary Glazing – this is often believed to be a much less efficient option, but this is not the case.

Click through for details of an independent study run by Historic Scotland which tested a number of insulation options including replacement and secondary glazed panes, and found that their U-values and heat efficiency were not far apart, although respective upfront costs and payback on investment are very different, with Secondary Glazing delivering very good value for money.

Reduce Noise in the Home with Secondary Glazing

Secondary Glazing gives extremely good noise insulation, even better than Double Glazing in the right circumstances. This is because it can be fitted with a wide air gap to the existing outer pane, as the air itself provides much of the insulation. It can also be “de-coupled” so that sound waves hitting the outer window are not automatically transmitted to the secondary pane, improving noise reduction further.

For more information on why Secondary Glazing is so effective, along with a video to illustrate the basic principles of sound reduction, click through to our Noise Reduction page.

Condensation Issues? Not with Secondary Glazing!

When it is cold outside and warm inside, the coldest surfaces in the room are usually the window panes. Because of this, moisture in the warm air is released when it cools at the windows, resulting in condensation. The result? You go to bed with dry windows and in the morning they are fogged up with a puddle on the window sill.

By insulating using Secondary Glazing, this is significantly reduced, if not eliminated altogether. You still need to ventilate to air the room, but this can be done when you are not there. Click through for more details and a video showing how effective Secondary Glazing can be against condensation.

Different Window Types and How to Insulate Them

There are certain types of outer windows that secondarydiyglazing.com get asked about, in terms of improving heat and noise insulation. These include uPVC double glazed windows on noisy streets, draughty sash windows, skylights, stone mullions and other types, where common features and methods become apparent over time for each one.

Click through for information that could be specific to your problem windows, where you might not be sure how to start or what part of the outer frames to use for the best insulation. We trust that the experience gained talking to customers and helping iron out a good way to proceed will be helpful to you!

Secondary Glazing and Alternative Window Improvements - Costed Case Study

Back in 2013 secondarydiyglazing.com conducted a study into common window insulation methods and their respective costs, for an upstairs flat with 8 large (draughty) sash windows. The difference in cost for a full-blown replacement window project and simple Secondary Glazing were, not surprisingly, very significant.

This study was updated early 2023, as a result of the winter energy crisis, where we included information as to relative efficiencies of each of the 9 options, along with the length of time heating energy savings would take to repay the outlay on each type of insulation.

Click through for descriptions of all measures examined, with the efficiency and cost analysis details.

Customer Gallery

Our customers share not just images of windows they are wanting to insulate, but also frequently the results of their endeavours, reflecting not just their neat DIY skills but their satisfaction with the insulation the Secondary Glazing is providing. If you click through to the gallery, we have grouped a selection of images by product, to help you picture what a similar installation will look like in your own home. In addition, there are images of particular window types, some indicating common obstacles to insulation, some showing successful projects, that may be useful.

There is an irony to the gallery as a whole, as a successful Secondary Glazing project often results in “invisible” panels, that blend into your windows and décor. When you fit our products, don’t be surprised that you forget they are there, until you get up really close to the window!

Less Obvious Benefits of Secondary Glazing

In addition to the major topics dealt with on this page, there are other issues that might be relevant to you – these are covered below:

Length of Life – Secondary Glazing panels can outlast purpose built units, as once the Double Glazing seal has broken, it loses insulation effectiveness and condensation will appear between the panes. As Secondary Glazing seals in a different way, it lasts as long as is needed. This approach allows the original windows to last for centuries if properly maintained.

Returning to Original Condition – fitting Secondary Glazing gives the option to simply remove it and return the outer windows to their original condition. Replacement with Double Glazing generally requires the complete and final removal of all original frames and features.

Repairability – a damaged or aged Double Glazed unit will usually need replacement of the glass as a sealed unit, as repair is not possible. However, Secondary Glazing can often be refreshed, by replacing the edgings or glazing sheet in the event of significant damage. On our 50+ year old Clipglaze system, for example, Tubeway get customers every year who after 20 or 30 years simply replace the flexible edging and clips, re-using the original pane.

Local Authority Approval – Secondary Glazing is generally easier to get approved, as it is can be fitted without being seen from outside and removed if required, which helps retain the character and appearance of buildings that are listed or under conservation status. This balances your energy saving with the principle of preserving important buildings. Note that you retain responsibility for checking with the relevant authority before going ahead with purchase and installation.

Insulating Air-Conditioned Property – The effective insulation of windows to prevent warm air being lost in winter can also prevent cooled air being lost in summer, should you live in a hotter climate where air-conditioning is necessary. In extremely hot locations be aware that excessive temperatures can have an effect on the adhesive systems, as it can dry out the adhesive tape, so please raise this with our Sales team if it is a concern.

Carbon Footprint – removal and disposal of your existing windows, the manufacture of full replacement Double Glazed units (which in turn may only have a 20 or so year expected lifespan), adds up to a lot of energy and resources. In contrast with Secondary Glazing, the lighter frames and simple glazing makes a favourable comparison of the Carbon Footprint between the two options.

Retrofitting – Because Easyfix Secondary Glazing systems can be installed on existing windows, within the skills and everyday tools of a modest DIYer, they are an attractive alternative to hiring professional tradespeople and buying bespoke products to improve your home. You can also remove and re-fit your Secondary Glazing panels each spring and autumn.

Glazing System Compromises

Secondary Glazing, along with other insulation and draught proofing, can deliver many benefits, but some can conflict. The most obvious is condensation versus heat, because the ventilation needed to remove warm moist household air in winter usually means replacing it with cool, dryer air from outside. Each householder will select the appropriate options for them, and we hope that the information on this website helps give the best result in every case.