Alex Hilliam, our Senior Researcher in Behaviour Change, fitted slimline double glazing to his Victorian flat in Edinburgh last year. It's now a more comfortable and energy efficient home as a result, but he had restrictions on the type of windows he was allowed to fit. This inspired Alex to revisit pioneering work that Changeworks completed in 2010, that changed planning regulations for Listed Buildings in Edinburgh. Here's what happened next.

Much of our housing stock in Scotland is old, and most of it will be here in 100 years' time (according to the Scottish Household Survey 75% of our homes were built before 1982, with 20% built before 1919). Many of these homes have been made in ways that make them historically important, and this can present a challenge for energy efficiency retrofit.

So what's the best thing to do to your older home? You will get many opinions on what you should do, and of course you are not always allowed to do everything you want to.

Houses in my street have every type of glazing possible, so when I wanted to fit double glazing to my house I thought I would just go to some suppliers, get some quotes, and get the windows fitted.

Because I live in a Victorian flat I thought I might live in a conservation area, whatever that was, but that wouldn't make any difference, right?

Well, wrong – it was a bit more complicated! A search on the Council website highlighted that I was indeed in a conservation area and that meant that I could fit double glazing (hurray), but that it had to be wooden. This confused me, as I've seen some houses in the area with plastic double glazed units.

We got quotes for wooden double glazing and for fitting 'slimline' double glazed units to our current frames – a technology that was developed to be fitted to heritage window frames. Surprisingly the slimline glazing was about the half the price, although some said our frames weren't up to it.

In the end we plumped for the slimline option – it was cheaper, the whole process was a lot cleaner and we didn't throw out perfectly useful original windows. They just took out the frames, put in the new glass and reinstalled the frames, rather than ripping the whole window out. The supplier we used also did a bit of maintenance to get the frames up to scratch.

Alex's wooden slimline double glazing unit detail

Wooden slimline double glazing detail

This whole process of exploring conservation areas, interpreting rules and choosing products got me thinking about a pioneering bit of work that Changeworks did a few years ago.

The City of Edinburgh Council, inspired by a our Double Glazing in Listed Buildings project and report, changed its planning policy in 2010 to allow the installation of slimline double glazing in listed properties − a huge step forward for energy efficiency in historic buildings. Inspired by our commitment to understand the impact of our work, and in part by my experiences, Changeworks has recently secured funding from the Scottish Government's Learning Network Challenge Fund to explore the fitting of double glazing to older properties across the country.

As part of this new piece of work we will explore:

  • If I lived in another local authority (and was in a conservation area or listed property) could I fit double glazing?
  • How is this policy working out in Edinburgh from the perspective of planners, installers and homeowners?
  • Does anything need to be done to help people get slimline glazing installed to older properties (where it is allowed)?


So we are embarking on a review of policies across Scotland, in particular for Listed Buildings, to see what glazing options are open to owners of these properties in different local authority areas. We are also exploring the journey for homeowners – what do installers, planning officers and even property developers think about the rules and what could be done to get more installs done?

The Learning Network Challenge Funding will allow us to use the Scottish Government's ISM (Individual, Social and Material) behaviour change tool to explore the issues in a workshop format with key stakeholders. We've been heavily involved in the roll out of this approach across the public, private and third sector over the last year and will use this in February for an Edinburgh focused workshop and in March, working with a local authority where the planning policies and challenges will be specific for that area. The March workshop will use a webinar format to enable interested parties from all over Scotland to listen in.

I will update on our progress in the next few months. If you have your own thoughts on this challenge, please get in touch.

Finally, the slimline glazing has transformed my house. It's so much more comfortable. The coldest room in the winter is now one of the warmest, in the summer we no longer have a 'cold side' to the house; and I still have my beautiful old window frames.


Alex Hilliam
Changeworks' Senior Researcher – Behaviour Change

Read more about the challenges of fitting slimline double glazing in traditional properties in Scotland in part 2 of Alex's blog.