Since April 2002, all replacement glazing has come within the scope of the Building Regulations. That means anyone who installs replacement windows or doors has to comply with strict new thermal performance standards (just replacing glass is exempt).

Reason for the change

The main reason is the need to reduce energy loss in order to meet increasingly stringent national and global energy saving targets.

What if I sell my house?

Your purchaser's surveyors will ask for evidence that any replacement glazing installed after April 2002 comply with the Building Regulations. There are two ways to prove compliance:
  • A certificate showing that the work has been done by an installer who is registered under FENSA or CERTAS Scheme or
  • certificate from the local authority saying that the installation has approval under the Building Regulations.


This scheme allows installation companies that meet certain criteria to self-certify that their work complies with the Building Regulations.
This was set up by the Glass & Glazing Federation, in association with all key stakeholders, and meets with central Government approval. A sample of the work of every installer is inspected by FENSA/CERTAS appointed inspectors to ensure standards are maintained and installers who fail to perform can be suspended or even excluded from the scheme.
FENSA/CERTAS also inform local authorities of all completed installations and issue certificates to householders confirming compliance.

Local Authority Building Control

Any installation done by a firm, which is not registered to self-certify, including work done as a DIY project by a householder, needs full local authority approval under the Building Regulations.


The house owner is ultimately responsible for ensuring the work complies with the Building Regulations.
It will delay or even stop the sale of your home if you cannot prove the replacement glazing was done legally.

Before buying replacement glazing

Be sure to ask whether the installer is able to self-certify. If not, an application will have to be made to your local authority for approval under the Building Regulations using the Replacement Windows and Doors form.

Additional Considerations

  • Structure - suitability of lintels and support above
  • Means of Escape - opening casements at first floor to be no more than existing to afford escape
  • Ventilation - Opening areas and background ventilation to be no worse than existing windows
  • Guarding
  • Opening casements below 800mm from floor at first floor to be suitably guarded.