Wood windows CO2T less

New Life Cycle Assessment (LCA) research revealed at Ecobuild showed that Wood Window Alliance (WWA) brandmarked windows are carbon-negative.

The study, carried out by the consultants Davis Langdon and commissioned by the WWA, is one of the first studies that measured empirically the embodied carbon of modern high performance wood windows applying recent developments in methodology.

Davis Langdon measured the embodied carbon of a selection of WWA windows with BFRC A and C energy ratings over 30, 60 and 100 year building service life periods using different exposure conditions and maintenance regimes1,2. The groundbreaking study used a methodology for calculating the embodied carbon for wood products derived from discussion and work within the Construction Emissions Community of Practitioners (CECoP) - an informal group of LCA practitioners and methodologists in the construction industry.

The study broadly applied the new PAS 2050 methodology, which was developed by BSi at the request of the government to provide a common approach for the assessment of the life cycle greenhouse gas emissions of goods and services. PAS 2050 is predicted to become the standard in the industry over the next few years for the carbon labelling of products and materials. The study used new information supplied by the WWA on CO2e emissions from waste management practices used in forest product processing as well as recently gathered data on end of life carbon emissions from recycling and landfill. And the results are noteworthy. Despite carbon emissions from transport, production, maintenance and end of life, the overall lifecycle of the wood windows measured in the study is carbon negative, provided the timber is from a sustainable forest and end of life issues are taken into account. The wood used in WWA windows is sourced from sustainably managed forests that sequester more carbon than they produce because the trees are used for window production are continually replanted. Ironically the new information means that each time you replace a wood window with another new wood window the more carbon you save (see graphs below), although there are clearly other environmental impacts to consider when aiming for a completely sustainable solution