FENSA certificate and CERTASS

A FENSA certificate proves that your replacement windows or doors meet Building Regulations and that the installer registered them with the council. FENSA and CERTASS are competent person schemes: they check their installers regularly and let them certify their own work, so you don’t need to involve building control. You get the certificate after the job, and you’ll need it when you sell.

How self-certification works

Replacing windows is building work, so it has to meet the double glazing regulations on energy, safety glass and escape. There are two ways to show it does:

• Use a registered installer. A FENSA or CERTASS installer notifies the council for you and issues a certificate. This is how nearly all replacement windows are done.
• Use building control. If the installer isn’t registered, or you fit the windows yourself, you apply to the council or a registered building control approver before the work starts. They inspect it and issue a completion certificate, and you pay their fee.

What the FENSA certificate shows

According to FENSA, the certificate confirms that the installation complies with Building Regulations, that it is energy efficient, that the installer registered it with the local council, and that an insurer stands behind the installer’s guarantee. In short, it’s the paperwork that proves the installer did the job properly. CERTASS issues an equivalent certificate for its installers.

Why the FENSA certificate matters when you sell

Your buyer’s solicitor will ask for evidence that any windows fitted since the rules began comply. Without a certificate, the sale can stall, and you may be asked for an indemnity policy or a retrospective inspection. Therefore, file the certificate with your house deeds as soon as it arrives.

The insurance-backed guarantee is a separate document

Your installer’s guarantee covers faults for a set period. An insurance-backed guarantee, issued by an insurer, protects that guarantee if the installer stops trading. FENSA notes it is a different document from the certificate, and that installations from the last decade or so are more likely to have one. Check you receive both.

If your FENSA certificate is missing

First, ask the installer who fitted the windows. If they’re no longer trading, FENSA and CERTASS can usually look up whether anyone registered the job and supply a copy for a fee. If nobody did, the council’s building control may be able to inspect the work and regularise it.

Checking an installer before you sign

Ask which scheme the firm belongs to and check the registration on the scheme’s own website. Then confirm the quote says the work will be certified, and how. Our guide to choosing a double glazing installer has the other questions worth asking. When you’re ready, get quotes and compare them with our quote checker.