U values as low as 0.85 W/m2K
Triple glazed as standard
Nationwide fitting or supply only
Choose from a wide range of colours
FSC® certified timber
Part Q compliant and Secured by Design options


Our best-selling triple glazed windows & door range for energy efficient projects.

 Green Building Store’s cost-effective range for replacement windows/doors,  retrofits and low energy newbuild projects. With FSC® certified timber, low U values and a range of designs and styles, our GBS-78 formerly named Performance range will enhance your project at a competitive price.

Our windows and doors are available in the following styles:


PERFORMANCE outward opening casement window

Tilt & turn

PERFORMANCE inward opening triple glazed window

Entrance door

Green Building Store PERFORMANCE triple glazed timber entrance door

French doors

PERFORMANCE French doors at Arts and Crafts house Sussex

Sliding doors

Green Building Store PERFORMANCE triple glazed timber Lift and Slide door

Bi-fold doors

Triple Glazed timber bifold door at Four walls retrofit

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