Adding a layer of glazing to single glazed windows

[applesandpumpkins]

Anyone done this? it's for sash windows. I'm wondering how much it will likely cost compared to just replacing them.

You mean secondary glazing

remember there’s no hermetic seal there do you will still get condensation

That’s so badly written 🫣

I meant
with no hermetic seal you’ll still get condensation

but yes we’ve had secondary glazing

We considered it and it was relatively inexpensive compared to replacing the single glazing. In laws have it and it works well for them. But they are very good at cleaning them. We’ve gone for double glazing, it’s eye watering as it’s wooden.

Secondary glazing can help if you want to keep your original windows BUT you do need to regularly open the windows, clean the secondary glazing and still remove condensation that is there. It's a good solution if you're prepared to do the work!

It massively reduces condensation though, in our case a fine mist in humid rooms ( that disappears once the cooking finishes etc) like the kitchen rather than enough to cause puddles on the windowsill, also no mould forming on the paintwork. We are doing it ourselves ( lots of DIY options available on line) but have worked out a couple of methods that work for the way our windows and shutters are set up, basically Perspex held on by magnetic strips inside a simple wooden frame attached to the stop beads or the window frame.

Thanks for the replies and help here. I wonder what the cost is compared to just getting them replaced? thinking either way it will be costly.

I fitted secondary glazing to my first house some 35+yrs ago.
Windows were metal framed so massive cold transfer & condensation.
The secondary glazing certainly helped but ultimately full replacement would have been more effective however I knew the house was only a stepping stone and I had no desire to make that kind of investment.

You can get magnetic plastic secondary glazing. We have huge windows (2m tall) and it was about £50 per window.

You can probably get your current windows refurbished and have brushes added to stop drafta which would be around £1000 a window for a equivalent size to ours or new windows will be maybe double that.

But if the windows are single glazed is it because the building is listed or you are in a conservation area?

I’ve got big windows and I’ve costed it out at about £100/ per window using 3mm Perspex and all the magnetic strips and the wooden trim I use etc. ( Perspex seems to be a bit more expensive now).

I’m in a listed building and some of my windows have 9 panes per dash so replacement wooden ones will have to wait for a richer owner!

But if the windows are single glazed is it because the building is listed or you are in a conservation area?

No, just because they're old and never been replaced. Thanks folks, sounds like magnetic is my best bet here.

When fitting secondary glazing, the trick to avoiding condensation on the glass is to seal the secondary glazing, to prevent warm moist air from the room getting into the gap, and to leave the original, outer window free to ventilate to the outdoors.

The pocket of still air between the two panes does the insulating.

Since you have sealed the inner pane, there will be no flow of air into the room causing a draught.

If you get condensation inside the room, onto walls or on the secondary glazing room side, you have a damp problem, which you can address by ventilating the damp out, and repairing the source of water.