Timber windows offer greater lifetime value, twice the expected lifespan of PVC windows, say UK researchers; PVC products have global warming potential of 160 kg of C02 over 60 years, timber equivalents reduce CO2 levels over same period, study finds

BERWICK UPON TWEED, UK , July 4, 2013 (press release) – One of the UK’s largest timber window manufacturers, Allan Brothers, has welcomed a new industry report that shows timber windows provide a greater lifetime value and twice the expected lifespan of PVC-u windows.

Dr Gillian Menzies, of the Institute for Building and Urban Design at Heriot Watt University, undertook the study for the Wood Window Alliance (WWA). The results provide direct comparisons for a range of timber window products manufactured to WWA standards against PVC-u windows in mild, moderate and severe conditions.

Danny Hughes, managing director of Allan Brothers commented, “This is a hugely important piece of research for the industry and one which Allan Brothers welcomes. It is important for consumers to be provided with facts to help them make the right decision financially and for the environment; it is great that this has come from such a respected source.”

The report tested timber-based and PVC-u window frames across 10 impact factors concluding that all timber window frames are more environmentally-friendly than PVC-u. The timber frames outperformed PVC-u in 9 out of the 10 tests by a considerable margin.

The report also revealed that timber window products actually have a negative global warming potential (GWP) meaning that over their 60 year + service life they actually reduce the amount of C02e in the atmosphere. In stark contrast, PVC-u products have a positive GWP with a difference of 160kgs C02e over the same period.

To put this in context, for an average three bedroom house with ten windows this equates to the equivalent C02e output of driving a petrol car for more than 4,000 miles – that’s equal to driving from Land’s End to John O’ Groats five times.

Product lifespan is another area Dr Menzies’ report concludes timber window frames excel in. In all tests timber windows had a service life of at least twice that of PVC-u windows. In moderate conditions, modified timber windows have an expected lifespan of over 70 years in comparison to the expected service life of PVC-u windows at just 30 years.

Mr Hughes added, “Many consumers see timber windows as premium products as the initial costs can be more than their PVC-u equivalent. However, this research shows that over their service life timber windows manufactured to WWA standards offer better value for money for consumers.”

In addition to the lifespan and environmental benefits the research also established that all timber window frames offer better long-term value than PVC-u. The Whole Life Cost study accounted for all capital, installation and maintenance events in calculating results giving a realistic and holistic representation of window cost. PVC-u was shown to have the lowest initial cost but 60-100 year cost comparisons revealed that all timber window products had lower lifetime costs than their plastic counterparts.

The full report can be downloaded from the Wood Window Alliance website at http://www.woodwindowalliance.com/professional/publications. An infographic summarising the key findings can also be found on the Allan Brother’s website.


Statistics and information taken from a report for the Wood Window Alliance, March 2013, by Dr Gillian Menzies, Institute for Building and Urban Design, Heriot Watt, Edinburgh.

The report is based on timber, modified timber and aluminium-clad timber window frames made to Wood Window Alliance Standards.

For more information see the final draft LCA report at http://www.woodwindowalliance.com/professional/publications.

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