FENSA (FENSA)
Self-certification for replacement window and door installers. Last reviewed April 2026 by the TradeMatch editorial team.
FENSA (Fenestration Self-Assessment Scheme) is a Building Regulations competent-person scheme for replacement windows and external doors in homes in England and Wales. Established in 2002 and authorised by the Department for Levelling Up, Housing and Communities, FENSA-registered installers can self-certify that their work meets Part L (energy efficiency) and Part Q (security in new dwellings) — bypassing the £200+ Building Notice fee and the Local Authority inspection wait. FENSA is the largest competent-person scheme for windows in the UK; the alternative is CERTASS.
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What does FENSA cover?
FENSA covers replacement windows, doors and roof windows fitted into existing openings. It does NOT cover new openings (which need full planning + building control), commercial buildings, or work in Scotland or Northern Ireland (different regulatory regimes). The FENSA certificate must be lodged within 30 days of work completion and registered with the Local Authority. Conveyancing solicitors will ask for FENSA certificates on any window work since April 2002 when you sell the house — without them, the buyer can demand a Regularisation Certificate (typically £200-£500 to obtain retrospectively).
Verifying a FENSA-registered tradesperson
- FENSA registration number — verify at fensa.org.uk before any deposit
- FENSA Certificate posted to your home (and lodged with Local Authority) within 30 days of completion
- Insurance-Backed Guarantee (IBG) — FENSA installers must offer one; reject any quote that does not include it
FENSA applies to these trades
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- Held in escrowFrom the moment the deposit clears until the job is signed off.
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FENSA FAQ
Do I always need FENSA for new windows?
For replacement windows in England or Wales — yes, unless the installer notifies Building Control directly (at extra cost). For new openings, conservatories, or Scottish/NI properties — FENSA does not apply; full Building Control approval is needed instead.
What if I lose my FENSA certificate?
Order a copy at fensa.org.uk — the certificate is registered to your address. Replacement copies are typically £25.
FENSA vs CERTASS — does it matter which?
Both are equally legally accepted competent-person schemes for replacement windows. FENSA is larger and better known to conveyancers; CERTASS is identical in legal effect. Either certificate satisfies the Part L self-certification requirement.
Do FENSA windows have to be U-value 1.4?
Replacement windows must meet the current Part L U-value standard (1.4 W/m²K from June 2022 onwards in England). FENSA installers self-certify the windows hit this; if your installer is not in a competent-person scheme, Building Control will check the U-value.
Why FENSA verification matters before any deposit
Lapsed accreditations are the most common silent failure on UK trade hires — registrations expire annually and not every trader updates their listing. Always verify the FENSA number on the public register on the day you sign, not at first meeting. On TradeMatch, every FENSA-registered tradesperson is independently re-checked before they can quote on your job, and the registration link is shown on their profile so you can confirm yourself.
Get a FENSA-Verified Quote
Up to 5 quotes from UK tradespeople — every FENSA-relevant member independently verified by TradeMatch. Escrow-protected payments. Reviews tied to completed jobs only.
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