Warm, secure and beautiful

Strong and secure, PVC-U/aluminium hybrid windows (WarmCore) come with multi-point locking, internal beading and are backed by a 10 year product warranty. Available as casement or tilt and turn windows, and with a flush sash option that brings the outer frame perfectly level with the opening part of the window - WarmCore windows are the perfect warm, secure and beautiful addition to any property.

Robustly designed to take the weight of triple glazed units as standard, choose this option for the ultimate thermal performance - at least 75% better than standard double glazed aluminium windows. Opting for 44mm triple glazing rather than standard 28mm double glazing reduces the whole window U-Value rating from 1.3 to 0.8.  Triple glazing is ideal for WarmCore windows installed in exposed locations.

Available in a range of styles and colours, Crystal's PVC-U/aluminium windows complete the WarmCore range!

Crystal's standard PVC-U windows and doors are available in a smooth grey profile to match the WarmCore range.

Download the WarmCore window retail brochure below or visit the download page where you can download a huge range of brochures and technical guides.

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Features and benefits

  • Available as casements, flush sash casements and tilt & turn
  • 28mm double or 44mm triple glazing
  • Class leading performance - 28mm double glazing = Uw 1.4W/M2K, 44mm triple glazing = Uw 1.0 W/m2K
  • 2 aesthetic rebate options - square or pencil round
  • Internally glazed for enhanced security
  • Stub cill available in 150mm, 180mm or 225mm options
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Available, as standard in a choice of 2 powder coated colours, WarmCore also allows you to pick a different colour for each side of the window. Want a colour outside with white inside to leave you free to change your interior in the future?  With WarmCore that's no problem


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Crystal Direct windows boast
huge benefits

  • Warranty

    Warmcore windows come with a 10 year manufacturer's warranty

  • Energy efficiency

    Marketing leading thermal performance due to PVC-U core

  • Security

    Secure By Design compatibility as standard provides peace of mind for end users

  • Quality

    Manufactured to the highest quality standards, fully accredited and CE 

  • Recycling

    End of life PVC-U products are given a new lease of life via recycling

Crystal directAccreditations

To find your local supplier use the search box below to get
a list of Crystal approved and Platinum partner
supplier locations
within your area.