If you are getting new windows and doors fitted, you should always check whether the company carrying out the work is FENSA registered. A FENSA registered company will carry the FENSA logo and is guaranteed to meet building regulations relating to double glazing in England and Wales. Choosing a business that is registered with FENSA will give you peace of mind about their competence and credentials.


FENSA is short for the Fenestration Self-Assessment Scheme. It is a government authorised Competent Person Scheme set up by the Glass and Glazing Federation, that lets companies fitting windows, doors or roof lights self-certify to declare that they meet building regulations for double glazing. While other schemes are available, FENSA is the most successful Competent Person Scheme in the UK to date.

What building regulations are involved?

Since 2010, all installers of replacement windows and doors must comply with government energy efficiency requirements as well as the government’s Approved Documents Parts L1B: Conservation of fuel and power in existing dwellings and K4: Protection from collision with open windows, skylights and ventilators (England) or N: Glazing safety in Wales. There are also other applicable sections of the Building Regulations where the replacements installed must be at least as compliant as the previous windows or doors. See the FENSA website for more information.

What can I expect from a FENSA registered company?

In order to be approved and carry the FENSA logo, companies applying to FENSA are thoroughly vetted. The registration process involves an inspection by FENSA and a competency check, and all businesses must hold adequate insurance. A FENSA registered company must provide customer contracts including transparent terms and conditions, and must provide guarantees that are clearly written.

As well as the initial inspection, FENSA registered companies are inspected on a regular basis to ensure that standards are maintained.

The FENSA database

You can search the database on the FENSA website to find a FENSA registered company in your area or, if you want to verify that a business carrying the FENSA logo is definitely registered with the scheme, you can also use the search to check their details. You can see our own FENSA record here.

Benefits of the FENSA scheme

Like other Competent Person Schemes, FENSA is there to provide reassurance that you can trust your glazing company. They save you the time and effort of checking out their background, giving you an immediate sign of quality and competence.

Using a FENSA registered company also has other benefits:

  • No need to register your window or door installation with the local authority – this is all covered by FENSA.
  • Make your voice heard about the work you’ve had done – you can provide feedback and a rating for your double glazing installer.
  • Insurance included – FENSA registered companies are required to have the appropriate insurance in place for “notifiable” work that your Local Authority needs to know about.
  • Certification is available – apply to FENSA for a certificate to demonstrate that your windows and doors are fully compliant.

To find out more about FENSA, visit the FENSA website.