Planning permission for new windows costs £1,393 in London where an application is needed: £695 drawings + £150 survey (£845 total) for our survey and drawings, and the council's £548 householder fee. For many houses the real answer is nothing, because the work is permitted development.
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Which group you fall into depends on four facts: whether the building is a house or a flat, whether it sits in a conservation area, whether the council has removed the right, and what the new windows look like. We take them in turn.
Do I need planning permission to replace windows?
Often not, if the building is a house. The government's technical guidance puts "general alterations such as new windows and doors" under Class A, and says it may be appropriate to replace existing windows with new uPVC double-glazed units (MHCLG technical guidance).
The condition that catches people is the look of the new window. Materials must be of similar appearance to the existing house, which the guidance says does not mean the same materials, but colour and style count. A flat sash window replaced by a top-hung casement with a chunky frame is the kind of change an officer notices.
When does it need an application?
Five situations, roughly in order of how often we see them:
- The building is a flat. The guidance says permitted development rights do not apply to houses which are flats, so permission should be sought (technical guidance).
- The council has made an Article 4 direction. It can remove the right across an area, and a planning application is then needed (article 4). Windows on a street front in a conservation area are the usual target.
- A condition on the original permission removes the right. Read your decision notice.
- The house is listed. Listed building consent is a separate consent that is usually needed for window changes; the heritage side is covered by our heritage statement cost post.
- The change breaks a condition of Class A, such as an upper-floor side window that opens low. Such windows must be obscure glazed to level 3 and non-opening unless the opening part is more than 1.7m above the floor.
Our permitted development checker works through these in three questions and tells you plainly if you need no application.
What does the application cost?
Our windows and doors service is £695 drawings + £150 survey (£845 total), with the survey included, and it covers the elevations that show each window as existing and as proposed, with frame sections where they matter. The council's householder fee is £548 for applications made on or after 1 April 2026 (MHCLG fee table).
The total is £1,393. If your project is a larger one that happens to include windows, the complete planning drawing service is £645 drawings + £150 survey (£795 total) and covers the whole application.
What persuades a council in a conservation area?
A like-for-like proposal, drawn clearly. Points an officer will look at include the glazing bar profile, the frame depth, whether sashes stay sashes and whether the material suits the street. On that last point, the guidance notes that in conservation areas cladding the exterior with render, timber or tiles is not permitted development (technical guidance).
Our elevations show the frame sections at a scale the officer can measure, and the written case says what is kept and what changes. A short heritage note is sometimes enough; a full heritage statement is for listed buildings and complex settings.
Frequently asked questions
Can I change only the glass and keep the frames? Often that is not a change to the external appearance of the house, and it needs no application. Check with the council or a certificate of lawfulness if you want it in writing.
Do I need building regulations for new windows? Replacement windows still have to meet building regulations standards, and your installer or building control can say how that is certified. A wider opening that removes part of a wall needs a beam calculation, which our structural calculations service covers.
Is the council fee different for a window-only application? No, it is the householder fee, £548.
Do you also do the building control side? Our building regulations drawings cover it where the work calls for a full set, for example a wider opening.
If the application goes through the Planning Portal, the Portal adds its own service charge: nothing, £99 or £149 including VAT, depending on the application type and complexity, paid to the Portal at submission and not normally refunded with a council fee (Ashford Borough Council, Planning Portal service charges, 11 September 2026). It is not ours and not the council's. Other submission routes exist; where your council accepts one without a charge, we can use it.
