Now the colder weather has officially set in, managing heat loss and damp in your home should be top priority. Leaving these problems unchecked will cause serious problems not just in your house but also your health and financial stability.
As of 2024, 89% of homes in the UK had full double glazing, but for those of us in Conservation Areas, Listed Buildings or just poorly maintained rented accommodation, dealing with the issues single glazing presents is especially important at this time of year.
Last year, in my 1700s stone cottage with (mostly) original windows I used bog standard film secondary glazing that literally uses double-sided sticky tape to adhere to the frames. It works surprisingly well so this year I’m investing slightly more to see if I see further benefits.
Why our home needed secondary glazing
We’re currently undergoing a total renovation of our 1700s stone cottage, removing the cement plaster to re-insulate and re-plaster our thick stone walls in lime. In this part of the house we have various mis-matched timber windows — from 1970s cottage style, to a unique horizontal sliding sash and original leaded casements (some cracked). While we’ve been able to upgrade to double glazing in the 1970s extension, we wanted to retain the character the old windows bring to the cottage. It is, however, very cold and often fogs up with condensation.
So we decided on secondary glazing. ‘Secondary glazing is an effective way of cutting heating bills and emissions, while reducing external noise, largely eliminating condensation issues and improving home comfort,’ explains Gareth Claase, Founder and MD of Gecko Glazing. ‘It's usually more cost effective than replacement windows, and, by upgrading what's there rather than replacing it, secondary glazing tends to be far better for the environment, as the original windows don't end up as landfill.’
This will be our third winter in the house so we’ve learned where the problem areas are and where we need to pay special attention. Last year, we made do with extremely basic plastic film insulation because ,while the works to the cottage were underway, we didn’t want to dedicate too much budget to installing semi-permanent secondary glazing until the messy work was complete. Some top of the line designs for secondary glazing are almost as good as double glazing, but there are also some budget-friendly options available.
‘All secondary glazing essentially works the same way,' adds Gareth. 'All different systems just trap a layer of (largely static) air between the original window and the secondary pane. This is a surprisingly effective insulator, cutting heat loss through the window by about half. Whether the secondary glazing material is high quality Plexiglass, like ours, or the cling film solution that's still quite common, actually makes very little difference thermally!’
How I installed the secondary glazing film
The secondary glazing package comes with the folded up plastic film and a roll of double-sided tape and you will need a measuring tape and a pair of scissors. I used warm soapy water to wipe down the frame first to give them a much-needed clean before sealing dust in there indefinitely and to ensure the sticky tape could adhere to the frame as best as it could.
This is the secondary glazing film I used in my house. I love how budget-friendly it is!
The plastic film feels ridiculously big while you’re unfolding it and I didn’t realise until I had stuck it to my frames that it was actually doubled up, so I had to do some in-situ surgery to make the plastic fit. If I were to do it again I would cut the plastic while it was still folded simply to make the rest of the process more manageable.
It’s best to start from the top and work your way around the frame with the sticky tape, removing the protective layer before starting the next section. I found I got the best results by overlapping the corners so the plastic could fully stick down.
Then I used a hairdryer on a hot but medium speed setting and began to tighten up the film. This bit was actually really fun to watch and will cover any bad cuts or saggy excess material.
And that's it! It look about 5 minutes per window, with the most of that dedicated to measuring and cutting the film.
Has the secondary glazing worked?
I’m using our spare room as a test to determine how well it has worked. No one sleeps in here regularly and it is away from the kitchen so the humidity is fairly constant. The windows are a large sliding sash window that currently doesn’t open and a small casement window that won’t fully close. The room is normally full of damp and draughts so I thought it would be a good place to see if there was a measurable difference.
To do this, I used a digital thermo-hygrometer (£8.99 from Amazon) to measure the temperature in degrees Celsius and the relative humidity levels (RHI).
Before adding the secondary glazing film:
- 9.30am with heating on: 18.6°C/62RHI
- 4pm no heating on: 15.3°C/74RHI
After applying the secondary glazing film:
- 9.30am with heating on: 17.6°C/ 63RHI
- 4pm no heating on: 16.4°C/ 66RHI
Although the differences are fairly small, there is definitely a difference in temperature drop throughout the day and humidity spikes with the film installed.
Beyond what the measurements say, I've definitely noticed that it feels warmer for longer in the room with the secondary glazing. The condensation is definitely less too, which means I don't need to wipe them down as often as I did.
‘Secondary glazing will reduce heating costs and emissions, reduce external noise and usually eliminate window condensation issues,” says Gareth. ‘By reducing internal drafts caused by convection, or those coming through poorly fitting windows, secondary glazing can mean that homeowners reach for the thermostat far less readily, and therefore the savings on heating bills can be surprisingly large.’
One of the more annoying things about this style of secondary glazing is that you can’t open your windows, so on clear days when you would like to air out the room and let some fresh air in, we were stuck using the air purifying setting on our dehumidifier or leaving a nearly door open.
Will I install it again next year or upgrade?
Although this is our second year of using plastic film glazing, I’m not sure if we will install it again. The packaging implies the film can remain in place and simply be tightened up with a hairdryer if you see it sagging, but I found the tape lost its stickiness and went yellow. So I'd definitely say it's a short-term temporary measure, rather than a long-term one.
The tape looks like it might also be tricky to remove and it may pull off some of the frame paint. Luckily, ours will be refurbished and repainted in the spring, so this isn't a huge deal, but if you’re renting, I’d be cautious about installing it.
Next winter, I hope we can upgrade to more permanent and more functional secondary glazing. I'll keep you posted on how we get on!
I also tried these three budget-friendly methods to draughtproof my house for the winter, and they were brilliantly effective, and if they work for my old cottage, they'll work for any home!