Windows & doors in Harrow: Planning Permission Guide
A guide to replacing windows and doors in Harrow — when you need planning permission and typical costs.
Based on 61 decided applications in Harrow over 12 months (41 granted, 20 refused).
Harrow has conservation areas around Harrow-on-the-Hill (a distinctive hilltop village with very strict design controls), Pinner, and Stanmore. Listed buildings are concentrated in Harrow-on-the-Hill and around Harrow School. Green Belt borders the north and west of the borough around Stanmore Common and Harrow Weald. Article 4 Directions cover parts of Harrow-on-the-Hill. The borough has a mix of inter-war semis, garden suburb character, and older village cores.
Recent windows & doors decisions in Harrow
The 5 most recent decided applications. Addresses redacted to postcode area.
Part conversion of dwellinghouse to create a separate self-contained 3 bedroom attached dwellinghouse; new access door to front; separate…
Certificate of lawful development (proposed): Replacement of ground floor front bay window
Certificate of Lawful Development (Proposed): Alterations and extension to roof to form end gables; windows in end gables
Installation of window to rear at first floor level; external alterations
Replacement doors and windows
These are borough-wide. See the 5 nearest to your address.
Check your address freePermitted Development Rules
Replacing or adding windows/doors may need planning permission in conservation areas or for listed buildings.
Replacing windows and doors like-for-like generally doesn't need planning permission. However, in conservation areas or listed buildings, changes to the appearance of windows and doors may require consent.
Typical Costs in London
Window and door costs depend on the number of openings, material choice, and style.
Typical total
Typically includes
Typically excludes
Highly variable depending on number of windows, material (UPVC vs timber vs aluminium), and style. Per-window costs typically £500–£1,500.
Get a personalised cost estimate based on your actual windows & doors dimensions.
Get my estimateWhich Professionals Do You Need?
Window replacements rarely need professional services. Suppliers typically handle measurement, manufacture, and installation.
This project is unlikely to need specialist professional services beyond a competent builder.
This type of project does not typically require architectural services.
This guidance is based on a typical semi-detached house with no special constraints. Listed buildings, conservation areas, and attached properties may require additional professional input.
Find out exactly which professionals you need for your windows & doors.
Get personalised guidanceConservation Areas & Listed Buildings
In conservation areas, changing window materials (e.g. timber to UPVC) or styles may need planning permission. Listed buildings always need Listed Building Consent for any window or door changes.
Properties in conservation areas often have reduced permitted development rights. Some project types (like side extensions) lose PD rights entirely. An Article 4 Direction can remove additional PD rights.
Listed buildings (Grade I, II*, or II) have no permitted development rights at all. Any external alteration requires Listed Building Consent in addition to any planning permission. An architect experienced in heritage work is essential.
Check if your property is in a conservation area or has other planning constraints.
Check my propertyFrequently Asked Questions
Just want a quick yes/no for your windows & doors?
Run our free 2-minute check to see whether your project likely qualifies as permitted development in Harrow — your address, your constraints, your council's own recent decisions.
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