MYTH 4: PVC WINDOWS ARE A GOOD THING TO INSTALL AND PAYBACK QUICKLY
The majority of non-listed buildings have had PVC windows installed, often sold as a sustainable solution with a ‘lifetime’ maintenance-free guarantee. But setting aside the highly toxic process in their manufacture, what does ‘lifetime’ really mean?
For a start, most of the glazing units will be double-glazed and these break down after just a few years, necessitating expensive replacement. All PVC products will also become brittle and eventually break down themselves in the presence of light, discolouring after a few years. You can now even buy PVC paint to overcome this, which means they lose their maintenance-free tag, the very reason they were promoted in the first place.
However, the biggest issue here is not the manufacturing process, their lifespan or even aesthetic considerations, but their payback cost, as on this basis they are one of the least effective measures you can install in a building to make them more sustainable.
A vast amount of research has been undertaken on this subject, most notably by Historic Scotland and the Sustainable Traditional Building Alliance (STBA). In simple terms, if you want to make your building more thermally efficient at reasonable or very little cost then do the simple things first as they make the greatest difference. This includes roof insulation, draught-proofing windows and doors, control systems, thermostatic radiator valves and even thick thermally lined curtains. The payback time for these simple measures can often be measured in months or just a few years, whilst the provision of new PVC double glazed windows will take on average over 30 years, if at all.
So if you want to save yourself significant money and help the environment, you now know what to do (and what not to).