The BSI ‘A’ rated conservation™ box sash timber window by Mumford & Wood

The latest news from Mumford & Wood announces the achievement of a BSI ‘A’ energy rating for the traditional timber Conservation™ box sash window. The Company can now claim this consistently high rating across the entire Conservation™ range of products.

This flag ship window is designed to directly replace an original box sash in older and period properties, or in new-build projects that are designed to achieve a truly traditional appearance with original features and operational functionality.  Added to the latest in timber window technology, which benefits from double glazing, excellent thermal performance and improved security, the Conservation™ box sash is one of Mumford & Wood’s highest specification products and has been tested to meet BS 6375 part 1 and 2.

“The energy rating results are calculated using our standard sections with a high performance glazing system,” says Stuart Judge, Sales & Marketing Director, Mumford & Wood.  “It’s a great result and we can now offer the best possible energy saving, period-replica, factory-finished window on the market.  The overall frame U-value is 1.4W/m2K which is well within the current Part L Building Regulations.”  The Conservation™ box sash also tested to air permeability Class 4 which is considered excellent for this design of window.

The Conservation™ box sash, almost indistinguishable from originals, features traditional weights, heavy duty brass pulley wheels and pre-stretched, durable nylon cords. 

The distinctive deep moulded internal profiles are available in a choice of Ovolo, Lambs Tongue and Fine Lambs Tongue glazing bar profiles and are complemented with Mumford & Wood’s standard sealing Sashglide®.

Products in the Mumford & Wood Conservation™ range, which includes the traditional sliding sash, casements, French doorsets and entrance doors, are made from premium quality, clear-grade, engineered timber which achieves outstanding levels of strength, stability and durability.

Please talk to a member of the Mumford & Wood sales team on 01621 818155, or visit for CAD drawing downloads, technical product information, case studies and applications.

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