Dempsey Dyer Windows, Doors & Conservatories

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Here at Dempsey Dyer we pride ourselves in the quality of our products. Over the years we've achieved a range of industry leading accreditations to show testament to the quality of our window, door and conservatory solutions in UPVC, timber and composite materials.

Below you can find details of our current range of accreditations. You can download copies of our current certification documentation by visiting the certificates section of our website.

Accreditation MarkDescription of Accreditation
BS7950 enhanced security windows

Enhanced Security Windows BS7950

Dempsey Dyer have met the requirements of the enhanced security windows BS7950 accreditation and are licenced by BMTrada.

BS644 timber windows

BS644 Timber Windows

Dempsey Dyer have met the requirements of the BS644 Timber Windows accreditation and are licenced by BMTrada.

BFRC rating scheme

BmTrada BFRC Rating Scheme

Our outward opening UPVC casement windows in 2800 series Deceuninck profile, along with our outward opening Timber casement windows (Dempsey II Stormproof) have met the requirements for an "A" rating with regards to the BFRC rating scheme. For additional information please visit our energy efficient windows page.

PAS 23/24

PAS 23 & PAS 24

Our ranges of Composite Doors, Timber Residential Doors and UPVC Residential & French Doors have all achieved a PAS 23 & PAS 24 rating.


BS 7412

We hold the BS 7412 accreditation in respect of our windows made from PVC-U extruded hollow profiles.


BS 7950

First granted in November 2001 we have retained this accreditation due to the enhanced security performance of our windows for domestic applications.

BSI registered company

BSI Registered Company

We operate a Quality Management System which complies with the requirements of BS EN ISO 9001:2008 for the below scope:

  • The manufacture of PVC-u windows and doors.
  • The manufacture of Timber windows, doors and conservatories.
secured by design

Secured By Design - Official Police Security Initiative

The following range of Dempsey Dyer products have met the requirements of the Secured By Design Official Police Security Initiative:

  • Dempsey II Stormproof Timber Casement Windows
  • Timb-A-Tilt Vertical Slider On Spiral Balances Windows
  • Timber Residential Doorsets
  • UPVC Open Out Casement Windows
  • UPVC Residential and French Doorsets
  • UPVC Tilt & Turn Windows
  • Composite Doorsets


Dempsey Dyer Ltd. has met pre-qualification requirements appropriate to public and private sector procurement.

CHAS accredited contractor


Dempsey Dyer Ltd. has met acceptable standards regarding the Contractor Health and Safety assessment scheme (CHAS).