FENSA certificate explained: what it is, when you need one and how to replace a lost one
By Glazing London,
Most people hear the word FENSA twice: once when new windows go in, and again years later when a buyer's solicitor asks for the certificate. This guide explains what it is, when you need it, and what to do if you cannot find yours.
The short answer
A FENSA certificate proves that replacement windows or doors in a home in England or Wales were fitted by a registered installer and meet the Building Regulations. Your installer registers the job and the certificate is posted to you. You need one (or an equivalent) for every replacement window or door fitted since April 2002. Repairs and new glass in an existing frame do not need one.
What FENSA actually is
Since April 2002, replacing a window or external door in a home has been building work that must meet the Building Regulations, mainly on heat loss, safety glass, ventilation and fire escape. There are two ways to show the council it does:
- The installer belongs to a competent person scheme such as FENSA or CERTASS. They self-certify the work and register it. The scheme notifies the council and sends you a certificate.
- You or your installer apply to the council's building control before the work, pay their fee, and an inspector signs it off. You receive a completion certificate.
FENSA is simply the best known of those schemes. It is not a quality mark for the windows themselves, and not a guarantee: the insurance-backed guarantee is a separate document.
Do I need a certificate? A quick decision guide
| The job | Certificate needed? |
|---|---|
| Whole replacement window or external door, frame and all | Yes, FENSA, CERTASS or building control |
| New glass or a new sealed unit in your existing frame | No, it is a repair |
| New hinges, locks, handles or gaskets | No, it is a repair |
| Secondary glazing fitted inside an existing window | No, the original window stays |
| A brand-new opening in a wall, or an extension | Yes, but through building control, as part of the wider work |
| Replacement rooflight or roof window | Yes, in most cases |
| Internal doors | No |
If you are in a listed building or a conservation area, planning rules are a separate question from Building Regulations. Our conservation area glazing page explains that side.
What the installer has to get right
To self-certify replacement windows, the installer has to meet the Building Regulations on several points. The main ones you can check yourself:
- Heat loss: the new window must meet the current energy standard, which our guide to how long double glazing lasts touches on.
- Safety glass in doors, beside doors and in low-level panes. See where safety glass is required.
- Ventilation: the new windows should not leave the room with less ventilation than before, which is why trickle vents often appear.
- Fire escape: bedroom windows on upper floors that served as escape routes must still open wide enough to escape through.
Lost your FENSA certificate?
This is the most common question we get from people selling a house. The steps:
- Check your house paperwork for a certificate, an installer's invoice or a guarantee. The installer's name and the year narrow the search.
- Request a copy from FENSA's website. You need the address and the rough installation date. If the job was registered, a replacement copy can be issued.
- Try CERTASS if FENSA has no record: the installer may have been registered there instead.
- Ask the council's building control whether a completion certificate exists for the address.
- If there is no record anywhere, the buyer's solicitor will usually suggest indemnity insurance, or you can apply to the council for a regularisation certificate, which involves an inspection.
Worth knowing: windows fitted before April 2002 never needed a certificate, so a solicitor asking for one for 1990s windows can simply be told the installation date.
How we handle it
We are FENSA approved for new windows and doors. When we fit uPVC windows, aluminium windows and doors or a new front door, we register the installation and the certificate is sent to you without any paperwork on your side, alongside the insurance-backed guarantee. Glass-only jobs such as misted unit replacement do not need a certificate, and we will tell you so rather than charge for paperwork you do not need.
Questions about a certificate for a house you are buying or selling? Message us on WhatsApp with the address and the age of the windows, or call 07915 903485.
FENSA, answered
What does a FENSA certificate cover?
It confirms that replacement windows, doors or roof windows in a home in England or Wales were fitted by a FENSA registered installer and meet the Building Regulations for that work. It lists the address, the number of windows and doors and the date of installation.
What is a CERTASS certificate?
CERTASS is another government-authorised competent person scheme for window and door installers. A CERTASS certificate does exactly the same job as a FENSA one: it shows the work was self-certified as meeting Building Regulations. Solicitors accept either.
What happens if you don't have FENSA?
If the windows were replaced after April 2002 and there is no certificate from FENSA, CERTASS or the council, a buyer's solicitor will ask why. The usual fixes are to find a copy, apply to the council for a regularisation certificate, or buy indemnity insurance. It rarely stops a sale, but it can slow one down.
How do you obtain a FENSA certificate?
You do not apply for one yourself. Your installer registers the job with FENSA when the work is finished, and the certificate is sent to you. If it was lost, you can request a replacement copy from FENSA's own website with the address and the installation date.
Do I need a FENSA certificate to replace a broken pane of glass?
No. Replacing glass or a sealed unit in an existing frame is a repair, not notifiable building work, so no certificate is needed. Safety glass rules still apply to doors and low-level panes.