Mumford & Wood's Conservation box sash is BBA-BWF compliant

Award-winning timber window manufacturer Mumford & Wood has announced a U-value of 1.1 W/m²K for the market-leading Conservation box sash.  

This product is the highest specification window in the comprehensive range of traditional and contemporary-style sash windows, casements, bi-fold, French doorsets and entrance doors and is designed to directly retro-fit in place of original box sash windows in older properties, or to create a traditional appearance in new builds.

Measurements have been tested in accordance with the new British Board of Agrément (BBA) and British Woodworking Federation (BWF) software tool in compliance with BS EN ISO 10077-1:2006.  

Test criteria is based on a timber density of 500 kg/m³, frame thickness of 160mm and casement thickness of 57mm.  Using a 16mm double glazed argon gas filled cavity, low emissivity coated glass and warm edge spacer, the thermal transmittance of 1.1 W/m²K is certificated to BBA-BWF-0261772.

The Conservation box sash is operated with traditional weights and pulleys and combines enviable period styling and features together with the very latest timber window technology to provide superb thermal and acoustic performance and improved security.

“Going forward the company will continue to submit all products in the extensive Conservation range for BBA-BWF measurement and compliance results,” says Owen Dare, technical director, Mumford & Wood, “and with products that achieve exceptional U-values in the new Part L Building Regulations, we are confident that the results will be equally impressive.”

Mumford & Wood use only sustainably sourced, engineered timber in their manufacturing process, which provides a strong, stable and durable product with an expected life of 60+ years.

Products are manufactured in accordance with the stringent criteria of the British Woodworking Federation’s Timber Window Accreditation Scheme, are fully factory finished and BSI Window Energy Rated.  Mumford & Wood’s products carry the BSI Kitemark, are Energy Saving Trust recommended and many meet PAS24 Secured by Design accreditation.