Secondary Double Glazing FAQs

Secondary double glazing is an additional layer of glazing that is added to an existing single glazed window. It involves installing a separate frame and window unit on the interior side of the existing window. The secondary glazing provides an extra barrier against noise, draughts, and heat loss, and is a far more cost-effective solution than replacing the entire window with a double glazed unit.

It does depend on what you mean by ‘best’.

If you mean … which secondary glazing solution reduces the most noise &/or provides the best sound reduction, then we think that science proves that our secondary double glazing is the best.

The primary reasons are due to the larger insulating air gap between the resultant panes of glass in combination with the manner in which we completely seal around the new door or window frame.

Check out the explanation & ‘U Value’ results on our ‘Save Energy Costs‘ page and you will better understand why we think that our secondary double glazing is not only better than other secondary double glazing solutions but also traditional double glazing.

Yes it most certainly does! Our secondary double glazing products have been manufactured since 1970 (for the over 50 years!) and it is estimated that between 4.5 to 5 million windows have had our secondary double glazing retrofitted to existing windows & doors in Britain and Europe. And, we have literally installed thousands of windows & doors in Australia. Please see the references from Australian customers on our homepage.

Whilst double glazing is eco-friendly because it reduces the need for energy to cool homes & houses in summer & heat them in winter due to thermal insulation benefits, we would argue that secondary double glazing is more eco-friendly because with secondary double glazing you don’t need to manufacture two panes of glass, but rather, only one new pane of glass is required.

Also, because there is a larger air gap with secondary double glazing, retrofitting double glazing provides better thermal insulation benefits, & so is thus more eco-friendly yet again!

Basically, the answer is “No”, as we install a new window or door inside the existing window or door. This is why we are oftentimes the only option for double glazing in strata title properties & heritage listed properties where the exterior of the property cannot be modified.

The only exception is in the case where the door or window must be installed externally, which is very rare.

As we install a new window or door inside the existing window or door, we make no modifications to the exterior of the property. This is why we are oftentimes the only option for double glazing heritage listed properties where the exterior of the property cannot be modified.

With secondary glazing, as we install a new window or door on the inside of the existing window or door, we make no modifications to the exterior of the building. This is why we are oftentimes the only option for installing secondary double glazing in a listed building where the exterior of the property cannot be modified.

With secondary glazing, as we install a new window or door on the inside of the existing window or door, we make no modifications to the exterior of the building. This is why we are oftentimes the only option for installing secondary double glazing in a strata titled apartment building where the exterior of the property cannot be modified.

No we don’t remove your existing windows. Our secondary glazing System is screwed to the inside of your existing windows.

If the secondary glazed window can fit inside the window frame (ie. the window handles don’t protrude too far) then measure inside the window frame.

If not, the window must be placed outside the window frame (called face fix). Then measure the window including the architrave at side, top & bottom.

The simple answer is yes. Secondary glazing is typically at least 30% cheaper than traditional double glazing.

And it is logical because with secondary double glazing we only need to supply one new pane of glass as compared to traditional double glazing where two new panes of glass are required.

We typically install our secondary glazing with screws no more that 400mm apart. And all our door & window frames are discretely siliconed in to close any gaps.

Yes we use 6.38 laminated glass this is made up of 3 mm glass, interlay and then 3 mm glass, all heat bonded together. All our glass is bought locally and we have deliveries to our factory approximately every 48 hours.

We will design our secondary glazed window so it can be opened to give you access to your openers where it is required.

Amazingly, it typically only takes approximately one hour to fit one of our secondary glazed window & then you can start obtaining the soundproofing & insulating benefits immediately. Additionally, there is little or no disruption as we do not have to remove & replace the existing window.

Please have a look at our Installation Videos page, where you will see just how quick & easy it is to install secondary glazed windows and just how little mess is created.

Condensation often occurs on single pane windows, normally in bedrooms &/ or bathrooms where you have a single pane of glass which is cold on the outside & warm inside. The condensation occurs on the inside.

If you install a retrofitted secondary glazed window in the bathroom or bedroom, the new internal window would be the same temperature as the room, therefore drastically reducing likelihood of any condensation forming.

So as to not effect acoustic or thermal performance, we recommend that if tinting is required, you tint your existing windows before installing our secondary glazed windows.

Magnetic secondary glazing involves installing a secondary window which is stuck to a frame around your existing window with magnets.

To open your window you have to physically remove the entire window. Just think about how would you go dealing with that … particularly for a large & thus heavy window … and what if you drop it!

And, in Australia, we understand that magnetic window suppliers (eg. Magnetite) are franchises & we have heard many stories of customers experiencing extended delay in delivery & installation as a result. As we are the manufacturers & own the business, our manufacture and installation process takes only 2-4 weeks.

We think in most cases that our solution is far better than magnetic secondary glazing. Contact us to find out why.

We offer 5 major types of secondary double glazed windows:-

1. Vertical Sliding Secondary Double Glazed Windows
2. Horizontal Sliding Secondary Double Glazed Windows
3. Hinged Secondary Double Glazed Windows
4. Lift Out Secondary Double Glazed Windows
5. Fixed Panel Secondary Double Glazed Windows

All of the above secondary windows are specifically designed to allow you to open the window to access y9our existing windows EXCEPT for Fixed Panel Secondary Double Glazed Windows. These windows are intended for use where the existing windows is not able to be opened & their purpose is  to allow light to enter while reducing sound, maintaining temperature and reducing drafts.