Do I need planning permission to replace windows in Harrow?

For like-for-like replacements in the same material and style, usually not. In conservation areas, changing materials or style may require planning permission. Listed buildings always need consent.

How much does it cost to replace windows?

Window and door replacement in London typically costs between £3,000 and £15,000 depending on the number of windows, material (UPVC, timber, or aluminium), and style.

Do I need Building Regulations for new windows?

Yes. Replacement windows must comply with Building Regulations for thermal performance. FENSA-registered installers can self-certify compliance.

Can I change my windows from timber to UPVC?

In most areas, yes. In conservation areas, the council may require you to keep timber windows. Listed buildings must retain their original window style.

Windows & doors in Harrow: Planning Permission Guide

A guide to replacing windows and doors in Harrow — when you need planning permission and typical costs.

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Windows & doorss in Harrow at a glance

80%

approved

£258

application fee

weeks typical

Based on 40 decided applications in Harrow over 12 months (32 granted, 8 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.

Council planning portal Pre-application advice

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Recent windows & doors decisions in Harrow

The 5 most recent decided applications. Addresses redacted to postcode area.

Granted

Replace window with door in ground floor front elevation; Replace window with window and door in ground floor rear elevation (Retrospective)

HA32026-03-29

Refused

Conversion of single dwellinghouse into two self-contained flats (1 x 2-bed 4 person and 1 x 3-bed 5 person), external alterations includ…

HA32026-03-29

Granted

Part front demolition and front extension with single access door; external alterations

HA12026-03-02

Granted

Variation of Condition 2 (approved plans) attached to planning permission PL/0707/23 dated 26.7.2024 to allow alterations of the door to …

2026-02-23

Refused

Non-Material amendment to planning permission PL/0139/24 dated 15/03/2024 to change a window to a door in ground floor front elevation

HA52026-02-23

These are borough-wide. See the 5 nearest to your address.

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Permitted 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.

Windows & doorsLondon

Typical total

£3,000–£15,000

Typically includes

Windows/doorsInstallationMaking good

Typically excludes

Planning application feeBuilding regs fee

Highly variable depending on number of windows, material (UPVC vs timber vs aluminium), and style. Per-window costs typically £500–£1,500.

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Which 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.

Architect / designerNot needed

This type of project does not typically require architectural services.

Structural engineerNot needed

Party wall surveyorNot needed

Planning consultantNot needed

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.

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Conservation 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.

Conservation areas

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

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.

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Frequently Asked Questions

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