Is FENSA a legal requirement?

No. Complying with building regulations is the legal requirement. Using a FENSA or CERTASS registered installer is simply the easiest way to demonstrate it, because they can self-certify instead of you applying to building control.

What if my windows were fitted without a certificate?

You can apply to your local authority building control for a regularisation certificate, or take out an indemnity policy, which is usually what happens at the point of sale. The indemnity is cheaper but covers the risk rather than fixing it.

Does FENSA cover doors too?

Yes, external doors that are more than fifty per cent glazed fall within the schemes. A solid external door is treated differently, so ask the installer to confirm what the certificate will cover.

Regulations · 01 of 11

FENSA or CERTASS: what is the difference?

FENSA and CERTASS are both government-authorised competent person schemes. Either lets an installer self-certify that your replacement windows meet building regulations and issue you a certificate. Neither is better than the other, and which one an installer belongs to matters far less than whether they belong to one at all.

Installers tend to present their scheme as the important one. In practice the schemes do the same job under the same regulations, and the question worth asking is simply whether the firm quoting you is registered with any of them.

What a competent person scheme actually does

Replacing a window or an external door in England and Wales is building work, and it has to comply with building regulations. There are two routes to proving it does.

Use a registered installer. They self-certify the work under their scheme, notify the local authority on your behalf, and send you a certificate. This is the normal route and it is included in the price.
Apply to building control yourself. You pay a fee, they inspect, and they issue a completion certificate. This is what you are left doing if your installer is not registered.

The certificate matters when you sell. A conveyancing solicitor will ask for it, and not having one means either an indemnity policy or a retrospective building control application.

The practical differences

FENSA is the larger and better known of the two, set up by the Glass and Glazing Federation. CERTASS is the main alternative and tends to be used by smaller independents. Assure is a third scheme doing the same job.

All three are authorised by government for the same purpose. The differences come down to the inspection regime, the complaints process and whether insurance-backed guarantees are bundled, and those vary more between individual installers than between the schemes.

What to check, and how

Do not take the logo on the quote as proof. Registration lapses, and logos outlive it.

Ask for the registration number, then check it on the scheme's own website.
Confirm the certificate is included in the price and not an extra.
Ask how long after completion it arrives. Weeks is normal; months means chasing.
If the installer is not registered, ask who is making the building control application and who is paying the fee.

An installer who is not registered with any scheme is not automatically a bad installer, but you are taking on the compliance paperwork yourself, and the quote should be cheaper to reflect it.

Questions

Is FENSA a legal requirement?: No. Complying with building regulations is the legal requirement. Using a FENSA or CERTASS registered installer is simply the easiest way to demonstrate it, because they can self-certify instead of you applying to building control.
What if my windows were fitted without a certificate?: You can apply to your local authority building control for a regularisation certificate, or take out an indemnity policy, which is usually what happens at the point of sale. The indemnity is cheaper but covers the risk rather than fixing it.
Does FENSA cover doors too?: Yes, external doors that are more than fifty per cent glazed fall within the schemes. A solid external door is treated differently, so ask the installer to confirm what the certificate will cover.

Note This guide is general information about England and Wales, not advice about your specific property. TrustedGlazing is an introducer and does not install, survey or quote. Rely on your installer's survey and your local authority for decisions about your own home.