Most people look for their FENSA certificate at one of two moments: a few weeks after new windows go in, when the paperwork has not arrived, or halfway through a house sale, when a buyer's solicitor asks for it. This guide covers both. It uses FENSA's own current figures, which differ from the older ones still repeated on a lot of pages, and it sets out what to do when there is no certificate to find. If you are still choosing a fitter, our guide to FENSA registration and finding a registered installer is the place to start, and the rest of our window and glazing guides cover the job itself.
What a FENSA certificate is and what it certifies
A FENSA certificate is the building regulations compliance certificate issued when a FENSA Approved Installer replaces windows or external doors and registers the job. FENSA says it proves the installation complies with Building Regulations, uses energy efficient products and is registered with the local council, and that the installer's warranty is insured. The energy side is the Part L requirement set out in our guide to Part L U-values and window energy ratings.
The certificate is attached to the home, not the person. FENSA says the name printed on it is only for postal purposes and does not affect its validity, so a certificate addressed to a previous owner still counts. If the details are wrong, the installer updates the registration and FENSA re-issues it.
FENSA's certificate is one version of a wider document. Six competent person schemes are authorised for replacement windows and doors in existing homes: Blue Flame Certification, CERTASS, Certsure, FENSA, NAPIT and ASSURE. Certass puts it bluntly: the correct name is a Building Regulations Compliance Certificate, and one from any scheme "is valid and serves the same purpose".
Not every glazing job produces one. FENSA's remit excludes conservatories, porches, new builds, extensions, repairs, commercial property, buildings taller than 18 metres, most supply-only jobs, and openings made wider so that new structural support is needed. Replacing a sealed unit in an existing frame is a repair, which is why replacing only the glass in a window comes with no certificate.
Do I need a FENSA certificate?
Not a FENSA one specifically. The law requires replacement windows to meet Building Regulations and the work to be notified. A FENSA certificate is one way to show that; a certificate from another authorised scheme, or sign-off from council building control, is another. FENSA's own page says that if your installer does not offer a FENSA certificate or another compliance certificate, you will need to pay for a building control inspection and should allow a few hundred pounds for it.
The same applies if you fit windows yourself. FENSA only issues certificates for installations completed by its approved installers, so a DIY job is signed off by building control. Our walkthrough of how to fit a double glazed window covers that step, and the should you fit your own windows check weighs the building control fee against a fitted price.
How to get a FENSA certificate after new windows
You do not apply to FENSA. The installer does the work, and FENSA describes four steps.
- The installation is completed.
- The installer registers the work on the FENSA Installer Portal. FENSA asks for this within 21 days of the job being completed.
- Checks may take place. Some installations are selected for inspection.
- The certificate is issued and sent to you, usually within 15 days of the job being registered.
Put together, that is up to about five weeks from completion, so a certificate that has not arrived after two weeks is not yet late. There is also a legal backstop: regulation 20(3) of the Building Regulations 2010 says the person carrying out the work must give the occupier a copy of the certificate not more than 30 days after completion. If you are still waiting, FENSA says your installer should be your first point of contact. Chase early: once more than 6 months have passed since registration, FENSA charges extra for a replacement.
The certificate should not be a large extra on your bill. FENSA's published scheme fees put the installer's cost of notification and certificate at £2.46 including VAT per job. A line on a quote headed "FENSA certificate" at a higher price is the installer's own charge, which is worth comparing when you are getting three quotes.
Lost FENSA certificate: ordering a replacement copy
If the job was registered, a copy is straightforward. On the FENSA website you search by address, using your postcode and door number, or by the certificate details if you know them. The copy costs £30 including VAT, paid by credit or debit card, and FENSA says it is issued and delivered within 15 working days. Some pages still quote £25 and a quicker turnaround; those figures are out of date.
You can also order by post. FENSA asks for a cheque for the same £30 with a covering letter giving the full company name and business address of the FENSA registered installer, and the homeowner's full name and the address of the installation, including the postcode. Other schemes run their own replacement services at their own prices.
| Scheme | Replacement copy | Notes |
|---|---|---|
| FENSA | £30 including VAT | Online by card or by cheque; delivered within 15 working days |
| Assure | £20 | Order from Assure Certification |
| Certass | Not published | Certass runs an online replacement service for its compliance certificates |
| Blue Flame, Certsure, NAPIT | Not checked | Ask the scheme that registered the job |
Sources: FENSA certificate ordering page and Help Centre; Assure Certification homeowner page; Certass website. Checked 23 September 2026.
When the search finds nothing
An empty result does not always mean the job was never certified. FENSA lists the usual reasons: the address or postcode is wrong, the job included more than replacing windows and doors, the windows or doors are inside the building, the company was not a FENSA Approved Installer at the time, or it did not notify FENSA when the job was complete. The first three need no action. For the fourth, search the other five schemes, because the job may be registered with one of them.
The fifth is the one to act on quickly, because the answer depends on the job's age. If the installation was completed within the last 2 years, start with the installer; if it is still not registered, tell FENSA through its form and it will follow it up. FENSA cannot register installations older than 2 years. For those, it points you to your local council for an inspection and a building regulations certificate. FENSA also says no party can hold the certificate as leverage, so it should not be held back to force a payment.
One piece of advice to ignore: that you can find another FENSA installer to inspect the windows and issue a retrospective FENSA certificate. FENSA certificates are only issued for installations completed by FENSA Approved Installers. There is no retrospective FENSA certificate for someone else's work; the council route below is the retrospective option.
The FENSA guarantee: the insurance-backed guarantee
People searching for a FENSA guarantee usually mean the insurance-backed guarantee (IBG). FENSA says that if your installer is FENSA Approved and the work is within its remit, you must receive both a FENSA certificate and an IBG policy. The IBG is a type of insurance the installer buys on your behalf, provided by an insurance broker, not by FENSA. It protects you if the installer stops trading and a fault appears that their warranty would have covered.
Government conditions for competent person schemes require financial protection for a minimum of six years from completion on work to homes, except where the client is a local authority or housing association. One IBG provider says most installers give 10-year guarantees, so 10-year IBGs are common, and that doors with less than 50% glazing are exempt. Keep the IBG with the certificate: the sale form asks for both.
Selling a house without a FENSA certificate
The seller's property information form, the Law Society's TA6 (6th edition, 2025), asks at question 5.1(a) whether you are aware of "replacement windows, roof windows, roof lights, glazed doors since 1 April 2002". If yes, 5.2(c) asks for copies of "planning permissions, building regulations approvals, completion certificates or competent person certificates", and question 6.1(d) asks for any unexpired guarantees on windows, roof lights, roof windows or glazed doors. The form never says FENSA. A certificate from any of the six schemes answers it, and windows fitted before 1 April 2002 fall outside the question.
If the certificate cannot be found, work through the options in this order.
- Search every scheme and ask your conveyancer what the local authority search shows.
- Get the job registered if a FENSA installer did it within the last 2 years.
- Apply for regularisation, the only route that makes the work authorised.
- Buy an indemnity policy, which can satisfy a buyer's solicitor but fixes nothing.
Regularisation: the council route and its cost
Under regulation 18 of the Building Regulations 2010, the owner can apply to the council for a regularisation certificate for unauthorised work carried out on or after 11 November 1985. The council inspects the work, and the Planning Portal warns that exposure, removal or rectification may be needed to show compliance. That applies even if the work was done before you owned the house.
Fees are set by each council and regularisation is VAT exempt. Oxford City Council charges £500 to regularise up to seven windows and two doors, which is its £333 fee before VAT plus 50%; approved in advance the same job costs £400 including VAT. Coventry City Council charges £277.50 plus £30 a window for replacement windows by an unregistered installer, so eight windows cost £517.50, against £185 plus £20 a window if you apply before the work. Older figures of £300 to £400 are below both 2026 schedules.
FENSA indemnity insurance: cost and when it is accepted
A building regulations indemnity policy is the quick alternative. One insurer, GCS Title, says its policy is also known as FENSA or lack of building regulations approval cover. It covers windows and doors completed at least 3 months before cover starts, with premiums from £20 including insurance premium tax, instant issue, a limit of up to £3m, and cover that runs in perpetuity. A conveyancing firm, SAM Conveyancing, quotes about £180 to £500, and says the policy does not cover personal injury from faulty workmanship and cannot be taken out once you have told the council about the work.
In a typical sale the seller pays and the policy is taken out in the buyer's and lender's names. Lenders set their own minimum cover: Leeds Building Society asks for at least the mortgage advance plus 10%, and Coventry Building Society at least the value of the property. A lender may not insist on a policy where the buyer's solicitor judges there is no reasonable likelihood of enforcement. FENSA's own view is that these policies may satisfy a solicitor's checklist but do nothing to show the installation is compliant, safe or efficient.
| Route | Cost | Does it make the work compliant? |
|---|---|---|
| Replacement FENSA certificate | £30 including VAT | Already compliant; the copy proves registration |
| Installer registers a late job (under 2 years) | No fee published | Yes, once registered |
| Council regularisation | £500 (Oxford); £277.50 plus £30 a window (Coventry) | Yes, once any remedial work is done |
| Building regulations indemnity policy | From £20 including IPT; £180 to £500 quoted by one conveyancer | No, it only pays on enforcement |
Sources: FENSA ordering page and Help Centre; Oxford City Council and Coventry City Council fees from 1 April 2026; GCS Title policy summary; SAM Conveyancing, updated 28 January 2025. Council fees vary; check your own.
Search every scheme before you spend anything, and do not call the council until you have chosen your route. That call is what closes off an indemnity policy.
Double Glazing Cost Calculator Team
How long can the council act? The 10-year enforcement limit
Under section 36 of the Building Act 1984 the council can serve a notice requiring the owner to pull down, remove or alter non-compliant work. If the owner does nothing within 28 days, the council can do the work and recover its reasonable expenses. Section 39(3) of the Building Safety Act 2022 changed the time limit in section 36(4) from "12 months" to "10 years" from completion. The change took effect in England on 1 October 2023 and in Wales on 1 July 2026.
The government's building control Q&A for England says the new powers are retroactive: they apply to any project still inside the time limit, whenever it started, and only section 36 notices served before 1 October 2023 stay under the old rules. We have not found an equivalent statement for Wales. Two other limits sit alongside it. A compliance notice cannot be given more than 12 months after the contravention. Prosecution under section 35 has no time limit, can lead to an unlimited fine or up to two years' imprisonment, and is usually taken against the installer.
Past 10 years a section 36 notice is time barred, but that is not the same as no exposure. Section 36(6) keeps the right of the council and others to apply for an injunction to remove or alter work that breaches the regulations, and no time limit is stated for it. How often councils use that route is not published.
Scotland and Northern Ireland
FENSA covers England and Wales only. Scotland has no equivalent for replacement windows because nothing is notified: Schedule 3 of the Building (Scotland) Regulations 2004 lists "a door, window, or rooflight when the work includes replacing the frame" as work not requiring a building warrant, on condition it meets the standards. Cutting down, building up or widening the opening does need a warrant. We have not found what a Scottish buyer's solicitor asks for instead, so ask yours. Northern Ireland is not covered here.
Get quotes from registered installers
The simplest way to have a FENSA certificate is to use an installer who issues one. Tell us what you need and Leads 2 Trade will arrange quotes from installers covering your postcode; ask each for its scheme and registration number.
Frequently asked questions
You do not apply for one yourself. A FENSA Approved Installer fits the windows or doors and registers the job on the FENSA Installer Portal, which FENSA asks them to do within 21 days of completion. Once the job is registered, FENSA issues the certificate and posts it to you, usually within 15 days. If it has not arrived, your installer is the first point of contact.
£30 including VAT, ordered from the FENSA website by searching your address or the certificate details, and paid by credit or debit card. FENSA says the copy is issued and delivered within 15 working days. A cheque route at the same price is also available. Assure charges £20 for a replacement of its own certificate.
You need evidence that replacement windows fitted since 1 April 2002 were certified, but it does not have to be FENSA's. The TA6 property information form asks for competent person certificates, building regulations approvals or completion certificates, and a certificate from any of the six authorised schemes answers it. If you have none, the options are finding it, regularisation through the council, or an indemnity policy.
Only for a job a FENSA Approved Installer did and failed to register. If the work was completed in the last 2 years, contact the installer, then FENSA, which will chase it. FENSA cannot register installations older than 2 years. FENSA certificates are only issued for work by FENSA Approved Installers, so for work by anyone else the retrospective route is a regularisation certificate from your council.
It is the insurance-backed guarantee (IBG) your installer buys on your behalf through an insurance broker, not from FENSA. It covers faults that the installer's warranty would have covered if the installer stops trading. Government scheme conditions require financial protection for at least six years from completion, and most IBGs run for ten.
One insurer's building regulations policy, which it says is also known as FENSA cover, starts from £20 including insurance premium tax for windows or doors fitted at least 3 months before cover starts. A conveyancing firm quotes a range of about £180 to £500. The policy pays out only if the council enforces; it does not make the windows compliant.
A section 36 notice to remove or alter non-compliant work can be served up to 10 years after completion. That limit rose from 12 months on 1 October 2023 in England and on 1 July 2026 in Wales. The government says the change applies in England to older work still inside the 10 years. An injunction under section 36(6) has no stated time limit.
No. FENSA covers England and Wales. In Scotland a replacement window where the frame is replaced does not need a building warrant under Schedule 3 of the Building (Scotland) Regulations 2004, though it must still meet the building standards. Cutting down, building up or widening the opening is different and does need a warrant.