The press has reported recently that residents in Poundbury want to install upvc windows rather than wooden ones because they are “greener.” But the idea that upvc windows are “greener” than wooden ones is for the birds. Sustainability works at three levels. Firstly, manufacturing. Wooden windows can readily be created from sustainable forests. Upvc ones are 43% oil and they require eight times more energy to manufacture. Secondly, “energy in use”, how warm they keep your home. Upvc and properly glazed timber windows are broadly similar though timber has become more efficient than upvc in recent comparisons (between 0.7 W/m2k and 1.2W/m2k for wood versus between 0.8W/m2k and 1.5W/m2k for upvc – low is good). Finally, longevity. Upvc windows last 25 years at most and only 3% can be recycled. Their incineration releases hazardous chemicals. Well-maintained, wooden windows can last for centuries and can be recycled or composted.
Game, set and match for wood.
The good people of Poundbury should be able to install secondary glazing: both wooden and, less good but recyclable, aluminium are available. But they should not fall for the self-interested blandishments of those trying to push a wasteful and pointless product which is well part its service date.