We’re delighted to announce that Build-It Magazine has awarded our P31 triple-glazed window ‘Best UK Window 2023’ in their annual Build It awards. Already our most popular window, this versatile, durable model took the win from a shortlist for its superb thermal performance, beautiful appearance and versatile design and specification options. 


The Build It Awards celebrate all aspects of self-build and renovation – from the very best completed projects through to innovative products and outstanding service from suppliers. 

Build It magazine’s annual awards scheme features over 25 categories, with hundreds of entries that cover major aspects of a home building project, as well as awards for outstanding conversion, turnkey new build projects and self build designers.

The awards are a great source of inspiration for everything from case studies of real-life self-build projects to high-performance glazing, cladding options and smart technology for your home.  

In action: the P31 has been used in domestic and commercial new builds, refurbs, Passivhaus schools & RIBA award-winning projects. 

Customisation: the P31 performs virtually identically in both all-timber and alu-clad timber options. 


As thermal standards for new-build homes continue to rise - and with increasing proportions of self-builders conscious of Passive House standards and low-energy building – it is important to choose windows and doors for your home that meet stringent criteria for performance and comfort.  

The versatile P31 window from Norrsken provides outstanding performance in an attractive model made using sustainably sourced timber, with a huge range of customisation options.


With an average glass u-value of 0.53 W/m2 K, and whole window U-values as low as 0.67 W/m2K, the window achieves performance suitable for Passivhaus and low-energy homes. 

Critically, it performs virtually identically in both all-timber and alu-clad timber options. 

The result is an incredibly adaptable window that is just as suitable, in its all-timber version, for traditional cottage renovations as it is as an alu-clad window in modern new build projects.


Visual appeal is essential in any window. The P31 matches a clean, square-edged design on the outside with a sleek, simple internal frame - although a decorative moulding finish is available on the internal frame. 

Designed to be minimal, the frame measures 26mm in thickness externally and 44mm internally while the opening sash sits at 54mm externally and 46mm internally. 

The P31 is a timeless window. Bespoke frame style, finish and hardware options ensure it blends with and enhances every unique project. 

For self-builders and renovators seeking a traditional feel, decorative glazing bars in either timber or alu-clad timber allow the P31 to suit unique designs without compromising outstanding performance and build quality. These glazing bars are not structural – so its glass u-value remains exceptional – but achieve the look of several smaller panes. 

Timeless: Seen here in RAL 7021 Black Grey Matt in a Yorkshire passive house, the P31 enhances projects of all types. 

The P31 is competitively priced as a premium window and comes with full PHPP data for self-builders or architects who are looking to use the system in Passivhaus projects.

It has been used on many residential new builds, renovations, Passivhaus schools & commercial multi-unit living.

See the P31 window in action 

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