Do I Need Permission to Replace Windows? (2026 UK)
For most houses, replacing windows is permitted development — you don't need planning permission. But replacement windows are notifiable under Building Regulations, so the work must be self-certified by a FENSA or CERTASS registered installer (or signed off by Building Control). The exceptions that do need permission are conservation areas, listed buildings, flats and homes with an Article 4 direction. Here's how it works in 2026.
Window replacement permission — quick answer
- Standard house, like-for-like: no planning permission (permitted development)
- Building Regs: always apply — use a FENSA/CERTASS installer or notify Building Control
- Conservation area: often restricted — check before changing style/material
- Listed building: Listed Building Consent usually required — even for like-for-like
- Flats / maisonettes: permitted development doesn't apply — check the lease too
- Article 4 direction: removes PD rights — planning permission may be needed
The certificate matters when you sell. A FENSA or CERTASS certificate (or a Building Control completion notice) is what conveyancing solicitors ask for. No certificate can mean indemnity insurance or retrospective sign-off, so always use a registered installer.
Window replacement: what permission you need, 2026 UK
The default: permitted development + Building Regs
For the great majority of houses, replacing windows in their existing openings is permitted development — no planning application. But the work is notifiable under Building Regulations (energy efficiency, safety glazing in critical locations, means of escape from habitable rooms, and ventilation). The clean route is to use a FENSA- or CERTASS-registered installer who self-certifies and issues you a certificate; alternatively, notify Building Control to inspect and sign off.
That certificate matters: conveyancing solicitors ask for it when you sell, and missing it can mean indemnity insurance or retrospective sign-off.
Conservation areas, listed buildings and flats
Conservation areas commonly restrict changes to window materials and style on elevations facing the highway, and some carry an Article 4 direction that removes permitted development rights — meaning you may need planning permission even for like-for-like. Listed buildings almost always need Listed Building Consent to alter windows, and uPVC is usually refused in favour of matching timber; unauthorised work to a listed building is a criminal offence. Flats and maisonettes don't benefit from the house permitted-development rights and you should also check your lease.
When in doubt, ask your local planning authority before ordering. Our vetted installers are FENSA/CERTASS registered — start a free quote, weigh materials in uPVC vs aluminium vs timber, or price the job with the cost guide and calculator.
Compare Quotes from FENSA/CERTASS-Registered Installers
Our vetted window installers are FENSA or CERTASS registered, so your replacement is self-certified and you get the certificate you'll need when you sell — free quotes, no obligation.
Frequently asked questions
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uPVC vs Aluminium vs Timber Windows
Frame materials compared — important in conservation areas.
Compare →Sources used in our 2026 figures
- gov.uk — Planning permission & permitted development
- FENSA — Building Regulations & certificates
- Historic England — listed buildings & consent
Methodology: Planning and Building Regs guidance reflects current England & Wales rules (June 2026); always confirm with your local planning authority, as conservation-area and Article 4 rules vary. Last updated .