8 November 2018. Jill Goulder

In 2015 three of us in Lewes, all beginners in video-making, got together to make an eco video about magnetic-strip secondary glazing, which we published on YouTube under the name Eco Lewes. Amazingly it’s now had well over 60,000 hits, and a flourishing crop of comments and queries, so I thought I’d celebrate that by writing a short piece for TTL about how it all came about.

I’m a Lewes Eco House owner, with my house quite well-known for featuring a very cost-effective secondary glazing approach using acrylic sheet, steel strip and magnetic strip. You can see my website, with an explanation of the secondary glazing system here: Magnetic Strip Secondary Glazing and also here: Magnetic Secondary Double Glazing

I and other eco-house owners open our homes every year or two as part of the Lewes Eco Open Houses weekend, and I get 100 or more visitors each time, all eager to see the mag-strip glazing. A few years ago I determined to make some sort of video to support my house-openings, simply to reduce the volume of questions from visitors about the secondary glazing: if they viewed the video first, they’d still want to come to see it in action but wouldn’t have to have everything explained from scratch.

What I’d realised was that there is virtually no commercial advertising of this lovely low-cost solution, as the materials are so simple and are mainly sold online by industrial-components suppliers for whom there’s no profit in advertising the materials to consumers. I concluded that I’d have to do the ad myself.

I recruited Neil Williams (then organiser of Lewes Eco Open Houses) and Olivier Sauer (our resident Lewes expert in installing magnetic-strip secondary glazing and advisor on draughtproofing: http://lewesbuilderdecorator.co.uk/); we filmed it, very much ad hoc and on a borrowed iPhone, at all three of our homes. I wrote the broad script and composed the ‘stills’, Olivier was the camera-man and film-editor, and I and Neil did our bit in front of the camera; I have to say that Neil, unlike me clutching my bit of paper, was a total natural. Well, it all worked! Amazingly we didn’t have to do many takes at all, and the stitching-together and info stills we managed pretty well. The video is called ‘Magnetic-strip secondary glazing for beginners’; it’s just over 9 minutes long, and includes a description of the system, why it’s such a good idea, how to install it, and where to buy the materials.

Incidentally, it’s really easy to set up a Youtube page. Go to YouTube, click ‘Sign in’ and follow instructions to create a Google account (or use your existing one if you have one. Bear in mind that your username will be the channel name). Once signed in, click on the Profile icon and then on Settings, and select ‘Create a channel’.

I really didn’t know what to expect from publishing our video on YouTube, but we’ve had a mass of enthusiastic responses, from the UK and worldwide – USA, New Zealand, Spain…. (One person wrote ‘I would like to say as a foreigner I just adore your accents’!!) It’s certainly encouraged people to embark on secondary glazing:

‘It was this video that convinced us to go ahead.’

‘Your video was so helpful it made our jobs so much easier. Just like to say a big thank you.’

‘Fantastic, thank you.  We’re about to move into an old cottage and was looking at secondary magnetic glazing, your video has shown me clearly how easy it is to do it yourself.’

‘Thank you for this great video. I was about to purchase ready made-up sheets and then came across this video. I’ve now done five windows myself with great savings. I have a grade 2 listed house so needed to find a solution that works within listing regulations and this definitely fits the bill. I’ve noticed a huge reduction in condensation (to pretty much none), warmer rooms and noise reduction benefits.’

Sound insulation seems from the comments to be an important ancillary reason for using mag-strip, as with the commentator who said ‘I did this to my flat 3 years ago; I’m renting the place so this is the best solution, I live next to a big junction and I can say this cut down the car traffic noise by 50% and the cold by 30%.’

Several viewers have come forward with questions about technicalities; I reply with my best info but say that I’m not a technical expert. I’ve had questions about condensation, maximum size of panels, use on sloping roofs, deterioration of the acrylic (none) and the adhesive (sometimes but can be reglued). Others rightly underline the importance of draught-proofing the window first and ensuring that the window-frame is flat and clean before applying the steel strip. The only slightly negative response has been from a German who (well, understandably) carps that British homes should all have been fitted with double glazing from the start!

I thought I’d end with a couple of pieces of useful information that I added over the last 3 years to the comments on the video. The first piece I forget the source of:

18% of all household energy is lost through windows alone, 26% through roofs & 33% through walls
 
30% of heat lost in a home can be due to draughts
 
Comprehensive draught-proofing can reduce fuel bills by 20%+ per year

Curtains reduce heat loss by 41%

Blinds and shutters reduce heat loss by 51%

Insulated shutters reduce heat loss by 61%

Modern roller blinds reduce heat loss by 22%

Double glazing reduces heat loss by 55% (U-value 3.14)

Secondary magnetic-strip glazing reduces heat loss by 63% (U-value 2.70)

Secondary magnetic-strip glazing can be around 15+ times cheaper than double-glazing!

Draught-proofing (using draught-proofing strips) around windows can reduce energy loss by 80%

Seasonal glazing film can increase temperatures in your home by 10% and cost from £2 per window!’

Then more recently I added this information kindly provided by Sarah Nicholl, who in her time in Lewes was brilliantly active in getting householders to adopt draught-proofing and magnetic-strip secondary glazing.

‘Extracts from an English Heritage 2010 publication called ‘Energy Efficiency in Historic Buildings: Secondary glazing for windows’:

The benefits of double glazing over other methods of window upgrading are often overestimated. Much of the comfort and energy efficiency benefits of new double glazing come from the reduction of draughts that will result from well-fitted window frames with integral draught-proofing. … With continual improvements in the performance of secondary glazing it may even be possible for the performance of secondary glazed windows to exceed that of new double glazing.

Heat losses from a typical traditional window are predominantly through gaps around the window. With larger windows the proportion of heat lost by conduction through the glass tends to be greater.

In terms of noise reduction, double glazed units are no better than single glazed units; and can be slightly worse for traffic noise. The important criteria for noise reduction are that the windows are well fitted and draught-proofed. Secondary glazing, with its larger gap between the panes, is a better sound insulator.’