Sash windows secondary glazing alternative

Many period homeowners want to do something about their sash windows’ thermal efficiency but don’t like the idea of sash windows’ secondary glazing.

We don’t blame them. Old sash windows can be draughty, cause damp issues and can make your home look older than you’d like. And secondary glazing may not solve all of these issues.

Thankfully, there is an alternative to secondary glazing, which we’re discussing in this article. First, though, let’s look at some issues with secondary glazing.

The issues with secondary glazing

Secondary glazing is a bit like putting a plaster on a cut that needs stitches, hoping that it will heal up just fine.

More often than not, if secondary glazing is done without any repairs taking place to the window, all of the issues you had with your windows will still be present. They will simply be hidden behind the second line of glazing. So, if you have damp issues because your windows are not stopping heat from escaping your house, you’ll still have damp issues as well as black mould on some occasions, but they will only affect the wooden window frame instead of the walls in your home.

If you had draft issues, these would still be there, but you may notice a slight improvement. There are several issues with secondary glazing; here are what most people experience, though:

Condensation issues

Most companies that install secondary glazing say that this type of glazing can solve condensation issues on the room side of the window. However, that isn’t actually solving the condensation issue. That is simply blocking it from entering the room.

Blocking it into what is basically a glass box surrounded by wood. This can cause a lot of issues with wooden window frames, and you may need to get them repaired due to rot a lot sooner than if the condensation issue had actually been solved.

Changes the appearance of your home

Secondary glazing companies will say that this type of glazing doesn’t change the appearance of your home from the outside at all. This is arguably true, but what about inside your home?

The outside appearance of your home is really important, but so is the inside. After all, you live inside your home and want it to feel and look nice.

Secondary glazing changes the appearance of the inside of your home a lot, and it can block the entire window sill from being used too.

It makes Windows difficult to use

We understand that opening a sash window with secondary glazing is as simple as opening the secondary pane and then opening the sash window.

But you suddenly have a two-step process to open your windows rather than just one.

Plus, as most secondary glazing companies don’t solve issues with cords, weights and latches, if your sash windows were difficult to open before the secondary glazing was installed, there is now another step, and they are still annoying and difficult to open!

Secondary glazing doesn’t solve damp or condensation issues; it just blocks them from entering a room. It restricts your use of the window sill and changes your view when you look out of the window. It also makes your sash window a bit more difficult to open.

Surely there is a better way?

After all, secondary glazing isn’t cheap, so isn’t it best to solve all of these issues and have secondary glazing?

Sash window reglazing with double glazing

Did you know that original box sash windows can be double-glazed?

This double glazing takes up hardly any room in the window frame and doesn’t change the appearance of the window in any way at all.

However, it keeps your home protected from thermal changes and does wonders for noise too.

We use vacuum-sealed double glazing for all of our sash window restorations that require double glazing, too. Vacuum-sealed double glazing is a fraction of the thickness of typical double glazing. 

Old double glazing for sash windows was 24mm thick. This meant that old double glazing often got in the way of using the window correctly and made the window very heavy.

The double glazing we use, though, is just 7 mm thick. And because it is vacuum-sealed, it has the same thermal properties as triple glazing, which is 44mm thick!

Installing double glazing into sash windows

A typical installation of double glazing for us begins with removing any rotten wood from the window frame and then adding fresh timber into the frame.

We can then add the new glass into the frame and add fresh putty to the glass, so it is draught-proof, and install the entire window back into the frame.

We will sand all parts of the window prior to installing the glass and then prime them and paint them to protect them from the elements.

A typical installation of double glazing in 15 windows for our expert team takes about ten days, depending on how many windows we need to install and the restoration work involved.

Can old sash windows be double-glazed?

Yes, they can. The beauty of using vacuum-sealed double glazing means that it can be retrofitted into existing sash windows.

Vacuum-sealed double-glazed, like LandVac has an extremely slim profile (just 7 mm), which means that it won’t interfere with the operation of the window, and it won’t change the appearance of the window at all.

This double-glazing technology offers the same thermal and noise properties as triple-glazing.

We retrofit double glazing into hundreds of sash windows a year. They look great and perform incredibly well compared to the old windows and secondary glazed windows too.

Thermal imaging of one of our sash windows double glazing projects shows how effective vacuum double glazing is in blocking heat loss

Double glazing can eliminate any damp and condensation issues you may have in your home at the moment. It won’t change the appearance of your windows from the inside or outside. And the operation of your windows will be perfect.

If you’re considering making your windows more energy-efficient, the best way to do it is with vacuum-sealed double glazing.

We are experts in installing this fantastic glazing technology. Please get in touch if you have wooden sash windows that are in desperate need of restoration and double glazing; you can check our prices here.