Assure is an official, UKAS-accredited Competent Persons Scheme authorised by the Ministry of Housing, Communities and Local Government (MHCLG) for the replacement of windows, roof windows, roof lights and doors in England and Wales

When it comes to improving your home with new windows and doors, it can be a daunting task to find a company that you can trust.

Choosing an Assure-certified installer to complete the work means you can rest assured that the installation complies with Building Regulations and is therefore legal and correct. You will even be sent a certificate to prove it. This should arrive within 28 days and proves that the work is registered with the local authority.

When you choose an Assure-certified company, homeowners are assured that...

  • Your installation complies with Building Regulations.
  • Windows and doors are the energy rated ones you ordered.
  • All installers and surveyors hold appropriate qualifications and are regularly audited to ensure that they are up to date with the latest regulations and have undertaken CPD (Continual Professional Development).
  • Your installation is covered by an insurance backed guarantee.
  • A sample selection of installations of every certified installer is independently audited by Assure to ensure regulations are being upheld.


Established since 1993 to assist in the elimination of unscrupulous traders from the home improvement market and to protect the consumer by regulating and raising standards of operation.

We are not tied to any particular trade and therefore our protection schemes apply to a wide range of products and services.

Only dealing with proven and accredited contractors, we fully vet them for professional competence and integrity which continues throughout the life of their membership.


TrustMark is the Government Endorsed Quality Scheme that covers work a consumer chooses to have carried out in or around their home.

When a consumer chooses a TrustMark Registered Business, they are engaging with an organisation that has been thoroughly vetted to meet required standards and has made a commitment to good customer service.TrustMark is the UK’s only Government Endorsed Quality Scheme. Our Scheme Providers and Registered Businesses work in accordance with our codes and charters as well as the codes of practice relevant to their industry. This means that when you choose a TrustMark Registered Business, you are accessing the most comprehensive level of protection available.

The TrustMark logo is a reassuring sign of quality and standards. TrustMark Registered Businesses are required to adhere to high standards of technical competence, customer service and trading practices, all underpinned by our Customer Charter, the Code of Conduct and the Framework Operating Requirements.