FENSA Certificates: What UK Homeowners Need to Know

Quick answer: A FENSA certificate is the document a FENSA-registered installer arranges for you after replacing external windows, doors, roof windows or roof lights in an existing home in England or Wales. It proves the work was self-certified as complying with the Building Regulations and registered with your local council, so no separate building control application was needed. The installer must register the job with FENSA within 21 days of finishing, and GOV.UK says you should have the certificate within 8 weeks. Lost it? Search the FENSA register by postcode and house number and order a replacement for £30 including VAT. No certificate at all? When you sell, the routes are a certificate from another competent person scheme such as Certass, a building control completion certificate, a regularisation certificate from the council, or an indemnity insurance policy. Each is explained below, with the trade-offs.

FENSA certificates are among the most requested documents in a house sale and among the most often lost, because the windows outlast the paperwork. This guide covers what the certificate is and is not, what it contains, the deadlines your installer is working to, how to find or replace one, and what to do when there is nothing to find. Every figure was checked against FENSA's own pages, GOV.UK and Approved Document L on 28 September 2026.

What FENSA is, and what it is not

FENSA (the Fenestration Self-Assessment Scheme) was set up in April 2002 by the Glass and Glazing Federation, with government authorisation, when the replacement of windows and doors in existing homes became controlled work under the Building Regulations. It is a competent person scheme: a registered installer can self-certify that the work complies, notify the council on your behalf and issue a certificate, instead of you applying to building control and paying its fee. FENSA has issued more than 13 million certificates and describes itself as the first and best known of the window schemes.

What it covers: the replacement of external windows, doors, roof windows and roof lights in an existing dwelling, in England and Wales.

What it does not cover: new conservatories, porches, extensions and new-build homes (all of which are covered by the building control process for the structure itself), repairs where the frame is not replaced, and commercial properties. Scotland and Northern Ireland have their own systems, covered below.

What it is not: a guarantee of workmanship. FENSA assesses its installers regularly, but by sampling their work, not by inspecting every job. The certificate says the installer declared the installation compliant and FENSA registered it; your protection against faulty work is the installer's guarantee and the insurance behind it, described later.

The other schemes. GOV.UK lists six authorised competent person schemes for replacement windows and doors in existing dwellings: Assure, Blue Flame Certification, Certass, Certsure, FENSA and NAPIT. A certificate from any of them has the same standing. Certass calls its document a Building Regulations Compliance Certificate; it has its own register and replacement service. Assure does not publish a certificate search tool, so for Assure installations you go back to the installer.

Why replacement windows need a certificate: the regulations behind it

Since 1 April 2002, replacing a window or external door has counted as controlled work because the new unit has to meet the energy-efficiency requirements of Part L. It also touches three other parts of the Building Regulations, and a FENSA installer is certifying against all of them:

• Part L (conservation of fuel and power). Approved Document L, Volume 1, 2021 edition, in force in England since 15 June 2022, sets the limiting standards for replacement elements in existing dwellings in Table 4.2. A replacement window must achieve a U-value of 1.4 W/(m²·K) or better, or a Window Energy Rating of Band B or better. A door with more than 60% of its internal face glazed must achieve 1.4 W/(m²·K) or a Doorset Energy Rating of Band C; any other door 1.4 W/(m²·K) or Band B. A rooflight must achieve 2.2 W/(m²·K). Paragraph 4.8 adds that the replacement must also be no worse than the element it replaces. The transitional allowance for timber windows (1.6 W/(m²·K) or Band C) ended on 14 June 2023. Where a window cannot meet the standard because the character of the building has to be maintained, paragraph 4.10 allows a centre-pane U-value of 1.2 W/(m²·K) or single glazing supplemented with low-emissivity secondary glazing. Wales publishes its own Approved Document L; check the Welsh Government version for a property in Wales.
• Part F (ventilation). The 2021 edition applies a no-worse-than-before rule: replacing windows makes a house more airtight, so the ventilation provision after the work must be at least what it was before. If the old windows had background ventilators (trickle vents), the new ones must too; if the house had no other purpose-provided ventilation, the installer will usually have to fit them. This is why new windows arrive with trickle vents that the old ones lacked.
• Part K (protection from impact). Safety glazing is required in critical locations: glazing in windows below 800 mm from floor level, and in doors and side panels below 1,500 mm.
• Part B (fire safety). Where an existing window served as a means of escape, the replacement must be at least as suitable: the Planning Portal's summary is an opening at least 450 mm high and 450 mm wide with a clear openable area of at least 0.33 m².

The installer's declaration to FENSA covers all of this. The certificate is the evidence that the declaration was made and registered.

What a FENSA certificate looks like and what it contains

A FENSA certificate is a single page headed with the FENSA logo. It carries:

• a unique certificate number, which is what FENSA and conveyancers use to look it up;
• the address of the property where the work was carried out;
• the name and FENSA registration number of the installing company;
• the date the installation was completed;
• a description of the work: typically the number and type of units, such as three windows and one door;
• a statement that the installation has been registered with the local authority as compliant with the Building Regulations; and
• on certificates issued after 6 June 2014, confirmation that the installer's written guarantee is insurance backed.

Older certificates were printed and posted. Recent ones are usually issued as a PDF by email, with a printed copy available. There is no photograph, drawing or product specification on the certificate: keep the installer's invoice, the product data and the guarantee alongside it, because those are what a surveyor or a future installer will actually want to see.

The timeline: 21 days, 8 weeks, and what to do if it never arrives

FENSA requires every job within its remit to be registered on the installer portal within 21 days of completion, and it monitors installers who register late. GOV.UK's guidance on competent person schemes says the installer will tell the local authority about the work on your behalf and give you a certificate within 8 weeks of completion. Between those two dates FENSA processes the registration, issues the certificate and notifies the council, which is why the installation later shows up in the local authority search a buyer's solicitor orders.

If 8 weeks have passed and you have nothing: first ask the installer for the certificate number, which they will have if the job was registered. If they cannot give you one, contact FENSA through its online contact form with the installer's name, your address and the completion date. FENSA can tell you whether the installation was ever registered. Get the promise of a FENSA certificate in writing, in the quote or contract, before the work starts; FENSA's own advice to homeowners is to do exactly that.

How to check whether your windows have a FENSA certificate

FENSA's search at forms.fensa.org.uk/fensa-certificate looks up installations by postcode and house number or name, or by certificate number if you have it. It covers every registration since 2002, so it works for a house you have just bought as well as one you have lived in for years. If it finds the installation, you can order a replacement certificate from the same screen.

FENSA lists the usual reasons a search finds nothing: the address was entered differently when the job was registered (a house name instead of a number, or a flat without its floor), the work was outside FENSA's scope (a conservatory, a porch, internal glazing or a repair), the installer was in a different scheme or none, or the installer never notified FENSA that the job was complete. Try the address variants first, then Certass's register, then the council: if a non-scheme installer notified building control, the council will hold a completion certificate.

How to get a replacement FENSA certificate

A replacement costs £30 including VAT. Online, you find the installation through the search above and pay by card. By post, FENSA accepts a cheque with the full company name and business address of the installer, the homeowner's full name and the address of the installation including postcode, and a separate mailing address if you want the certificate sent elsewhere. FENSA's ordering guidance says to allow up to 15 working days, and digital copies usually arrive well inside that. You cannot order a replacement for an installation that is not on the register, because there is nothing to reissue; that situation is covered next.

Selling a home with no FENSA certificate

The Law Society's TA6 Property Information Form, which sellers in England and Wales complete for the buyer, asks whether windows, roof windows, roof lights or glazed doors have been replaced since 1 April 2002 and what evidence of Building Regulations compliance you hold. The 6th edition of the form has been mandatory for conveyancers since 30 March 2026; the question has been there in one form or another since the 2002 rule change. Answer honestly, including "not known" where that is the truth: the form is a representation you can be held to. Then work through the options in this order.

1. Find the registration. Search the FENSA register, then Certass's. A surprising number of "missing" certificates were issued and never reached the homeowner, particularly where the installer's office handled the paperwork after completion.
2. Ask the installer. If the company is still trading and still a scheme member, it can register a job late; FENSA monitors late registrations but does not refuse them. Give the installer the completion date and ask for the certificate number.
3. Ask the council for a completion certificate. If the installer was not in a scheme and did the right thing, they applied to building control under a building notice and the council issued a completion certificate. The council's building control records, searchable through its planning and building control portal or by email, will show it.
4. Apply for a regularisation certificate. This is retrospective building control approval for work carried out without it. It is available for work started on or after 11 November 1985. You apply to the council with a description of the work; a building control surveyor inspects, may ask for parts of the installation to be opened up, and can require anything non-compliant to be put right before issuing the certificate. The fee is set locally, commonly around 150% of the equivalent building notice charge and not subject to VAT. It is the only route that actually confirms the windows comply, which is why it is the one a cautious buyer's solicitor prefers and the one most sellers avoid, because of the time, the cost and the risk of being told to change something.
5. Buy an indemnity insurance policy. A lack-of-building-regulations or FENSA indemnity policy is a one-off premium, arranged by the conveyancer, that pays the cost of enforcement action if the council later requires the work to be altered or removed. Standalone FENSA policies start from under £15 including insurance premium tax and most cost between £50 and £200 depending on the property value and insurer. The policy passes to future owners. It has three limits that FENSA itself has warned about: it does nothing to confirm the windows are safe or compliant, it does not pay to repair or replace defective units, and it is voided if you contact the council about the work, so once the policy route is chosen nobody can ask building control to look.

The enforcement reality. Under section 36 of the Building Act 1984 a local authority must serve a notice requiring work to be altered or removed within 12 months of the work being completed. For windows fitted years ago the practical risk of enforcement is close to nil, and that is why indemnity policies are cheap. The risk that remains is commercial: a buyer's lender or solicitor insisting on evidence, and a buyer using the gap to negotiate on price. That is a reason to keep the certificate, not a reason to worry about the council.

The insurance-backed guarantee on certificates after 6 June 2014

Installers registered with a competent person scheme are required to provide insurance behind their written guarantee, so that if the company ceases trading the guarantee is still honoured. FENSA says certificates issued after 6 June 2014 verify that the installer's warranty is insured, and its homeowner pages describe the insurance-backed guarantee (IBG) policy issued by an insurance broker for installations completed after 2014. The IBG is a separate document from the certificate. Ask the installer for it at handover, check the policy number and the term, and file it with the certificate: if the installer folds in year six of a ten-year guarantee, the IBG is the only thing that pays for the failed sealed unit.

FENSA inspections, installer registration and complaints

Homeowners search for "FENSA inspection" expecting FENSA to inspect their windows. It does not, as a rule. FENSA assesses each registered installer regularly by visiting a sample of their completed jobs; the assessment is of the installer's standards over time, not a check on your installation. Before you sign a contract, use FENSA's Find a FENSA Approved Installer search by postcode, company name or registration number to confirm the firm is currently registered, and check the registration number on the quote matches. If something goes wrong with the work, complain to the installer in writing first; if that fails, FENSA has a complaints process for work registered with it, and the IBG covers you if the installer has stopped trading.

Scotland and Northern Ireland

FENSA operates in England and Wales only. In Scotland, replacing windows and doors like for like generally does not need a building warrant from the local authority's building standards service, but the new units must still meet the Building (Scotland) Regulations, and a warrant is needed if an opening is enlarged, reduced or created. Some installers in Scotland provide a certificate of compliance through their trade body; ask for whatever documentation the installer offers and keep it. In Northern Ireland the competent person schemes do not apply and replacement windows are dealt with by the council's Building Control service, which issues its own completion certificate. In both countries, when in doubt, the local authority is the right first call.

Planning permission is a separate question

A FENSA certificate is about the Building Regulations, not planning. The Planning Portal's guidance is that you do not usually need planning permission to replace windows and doors with ones of a similar appearance, but you do need listed building consent for a listed building, there may be additional restrictions in a conservation area, a national park or an area of outstanding natural beauty, and some councils have made Article 4 directions withdrawing the usual permitted development rights, often precisely to control replacement windows in period streets. New upper-floor side windows must be obscure-glazed and either non-opening or more than 1.7 metres above floor level. Leaseholders may also need the freeholder's consent. Check planning before the windows are ordered, because an installer's FENSA certificate will not cure a planning breach. Our guide to planning permission records covers what to keep.

Keeping the certificate: where it belongs in your property logbook

File the FENSA certificate with the installer's invoice, the product specification (including the U-value or energy rating and the trickle-vent details), the written guarantee and the insurance-backed guarantee policy. Together they answer every question a buyer's solicitor, a surveyor or a future installer will ask. They belong in the same place as your gas safety certificate, EICR, boiler service records and solar installation records: the guide to what goes in a property logbook lists the full set, and the sales pack readiness check will tell you which of them you are missing before a buyer does. Hand the whole file to the buyer on completion; the certificate is transferable and the guarantee usually is.

Frequently asked questions

Do I need a FENSA certificate to sell my house?

Not legally, but the TA6 form asks about replacement windows since 1 April 2002 and the evidence you hold, and the buyer's solicitor will expect a competent-person certificate or a building control completion certificate. Without one you will usually be asked for a regularisation certificate or, far more commonly, an indemnity policy.

How do I find my FENSA certificate?

Search the FENSA register at forms.fensa.org.uk/fensa-certificate by postcode and house number or name, or by certificate number. If nothing shows, the work was outside scope, in another scheme, notified to building control directly, or never registered.

How much does a replacement FENSA certificate cost?

£30 including VAT, by card online or by cheque. Allow up to 15 working days; digital copies usually arrive sooner.

What does a FENSA certificate look like?

A single page with the FENSA logo, a certificate number, the property address, the installer's name and registration number, the completion date, a description of the units installed, and confirmation of registration with the local authority; after 6 June 2014 it also confirms the guarantee is insurance backed.

How long does it take to get a FENSA certificate after installation?

Installers must register within 21 days of completion and GOV.UK says you should have the certificate within 8 weeks. Chase the installer first, then FENSA.

What if my installer was not FENSA registered?

You should have a certificate from another scheme (Certass, Assure, NAPIT, Certsure or Blue Flame Certification) or a building control completion certificate. If neither exists, the routes are regularisation or indemnity insurance.

Is a Certass certificate the same as a FENSA certificate?

For Building Regulations purposes, yes. All six authorised schemes carry the same standing with conveyancers.

Does FENSA cover Scotland or Northern Ireland?

No. Scotland uses building warrants (not usually needed for like-for-like replacement) and Northern Ireland uses council Building Control.

Does FENSA apply to conservatories or new-build homes?

No. New conservatories, porches, extensions, new builds, repairs that keep the frame, and commercial buildings are all outside FENSA's scope.

Related guides on logbook.co.uk

• What goes in a property logbook: the full document list
• Conveyancing documents checklist for selling a home
• Planning permission records: what homeowners must keep
• Material information in property listings (Parts A, B and C)
• Property logbooks in the UK: the complete guide
• Your home's public record: free checker for EPC and sold-price history by postcode

Sources

Every figure above was checked against the following on 28 September 2026.

• FENSA: Homeowners (scope, exclusions, insurance-backed guarantees), About FENSA, Why you should always ask for a FENSA certificate (6 June 2014 insurance statement), Register your work in 21 days and Find and order your FENSA certificate (£30 fee, search, reasons a certificate is not found)
• GOV.UK: Building regulations approval, use a competent person scheme (certificate within 8 weeks) and Competent person scheme: current schemes (the six window schemes)
• Approved Document L, Volume 1: Dwellings, 2021 edition incorporating 2023 amendments (paragraphs 4.7 to 4.10 and Table 4.2)
• Planning Portal: Doors and windows, building regulations and planning permission
• LABC: Replacement windows and trickle vents (Approved Document F 2021)
• The Law Society: TA6 Property information form (6th edition)
• Planning Portal: Regularisation
• Certass: Competent Person Scheme

First published 17 April 2026. Rewritten and re-checked against the sources above on 28 September 2026 by Jamie Dawson, Editor. Logbook.co.uk is independent of FENSA, the Glass and Glazing Federation and the other schemes; this guide is general information, not legal or conveyancing advice. Corrections: corrections@logbook.co.uk