Plastic windows are often put into older buildings, to ‘upgrade’ old single glazed wooden windows. They can provide improvement in insulation via double-glazing and improved draft-proofing and so are often viewed as the sustainable solution. This is belied by their limited longevity, the PVC-U they are manufactured from gives them an expected maintenance free life of not much more than 30 years, at the end of which it is more likely that they are discarded and replaced than maintained. There is a huge carbon footprint created in their manufacture and replacement and waste plastic is an increasing environmental problem.
Old sash Windows don't have to be as beautiful
and rare as those on this Queen Anne townhouse
to be well worth preserving and restoring.
Wooden window frames and sashes of whatever age can be easily repaired if they have not been allowed to rot, though sliding sash windows in particular are often seen by the inexperienced as more trouble than they are worth to restore. However weights, sash cords and other traditional sliding sash accessories are readily available from specialist suppliers and slender, pre-manufactured double glazing units can be used to replace original Victorian glass, which was often especially thick in larger windows. An expertly restored wooden sliding sash should be no harder to open and close than a UPVC replacement and will let in more light than a thicker framed plastic window, as is noted in the Building Regulations.
Marine Court, St Leonards, a 1930’s work of art made more
ordinary by the later, indiscriminate insertion of randomly
chosen windows and the infilling of balconies in the
apartments to the left. The sustainable solution here
is not obvious
UPVC can now be recycled and one major manufacturer of window profiles and other parts recycles up to 90% of old UPVC windows, including the glass, on their site in Derbyshire, though even this process has a carbon footprint in the energy used. The RecoVinyl Scheme is a European wide initiative to collect and recycle used PVC building products to support the Vinyl 2010 Voluntary Commitment. The British Plastics Federation claims that, since inception of the scheme, the UK has led the way in the volume of PVC collected and recycled in Europe. The question is, how many discarded UPVC window actually do get recycled? Figures are lacking and it may be that too many still go to landfill and incinerators.