Do I need Building Regulations approval for replacement windows?

Replacement windows are subject to Building Regulations, and compliance is normally demonstrated either through a competent person scheme registration or through a building control application. Confirm with your installer which route applies to your work before it starts.

Should doors be replaced at the same time?

Usually yes. Doors are the most visible elements on most elevations, and matching them later to an existing colour and system is harder than doing them together.

How far ahead should I start planning?

Allow time for design, quotation, order, survey and manufacture. Lead times vary by system and time of year, so ask for current lead times as part of the quotation rather than assuming.

Installation · Flagship guide

What Should I Think About Before Replacing Every Window in My House?

Decide the whole house before you order any of it. A whole-house programme is one design decision repeated thirty times, not thirty separate decisions.

3 min read

Written by Windows in the Lakes · A trading name of Home Glazing Ltd · Last reviewed 21 September 2026

Short answer

In short: the work that determines whether a whole-house replacement goes well happens before anything is ordered — establishing the planning position, setting one specification for the entire property, agreeing what happens to internal finishes, and sequencing the work against anything else you are doing to the house.

This guide is the checklist we work through with homeowners planning a full programme, in roughly the order it matters.

1. Establish the planning position first

Before any design work, find out whether the property is listed, in a conservation area, subject to an Article 4 direction or within a National Park. These affect what can be installed, sometimes differently on different elevations, and they are far cheaper to establish now than after a specification has been agreed. The position depends on your specific property, its history and your proposal, so confirm it with your local planning authority.

2. Design the elevation, not the window schedule

Work from straight-on photographs of every elevation.
Decide the division of each opening and which lights open, across the whole house at once.
Check escape window requirements for bedrooms and habitable rooms with your building control body.
Settle one frame colour, one hardware family and one glazing approach.
Decide where doors and glazed doors sit in the programme — they are usually the most visible elements.

3. Set the budget against the whole house

Whole-house costs are driven by unit count, opening sizes, material, glass specification, access and how much making good is included. Our whole-house cost guide and the Project Investment Planner are the right places to build a realistic figure before requesting quotations.

Biggest cost drivers: Unit count, opening sizes and material
Most underestimated: Making good, decoration and access
Best value decision: Doing the whole property in one specification
Most common regret: Phasing without recording the specification

4. Agree what happens to the inside

Window replacement disturbs plaster, reveals, cills, curtain fittings and decoration. Establish in writing what the quotation includes — internal making good, external sealing, removal and disposal — and plan decoration afterwards rather than before.

5. Sequence against your other work

If you are also rendering, re-roofing, extending, fitting a kitchen or laying floors, the order matters and scaffolding can often be shared. Our guide to the order of works covers the common interfaces.

6. Understand the process before you commit

01Design consultationWe look at the house, the elevations and the constraints.
02Specification and quotationAn itemised quotation covering products, glass, hardware, installation and making good.
03OrderYou decide to proceed on a clear scope.
04Detailed surveyAfter order, every opening is surveyed and final manufacturing information is confirmed with you.
05Manufacture and installationProgrammed by elevation, with the house kept secure and weathertight throughout.
06Handover and certificationIncluding the relevant Building Regulations compliance route for the work.

Sources and further reading

Regulatory and technical points in this guide should be checked against the current published guidance below, and against the specific circumstances of your property.

Guidance last reviewed 21 September 2026 by Windows in the Lakes

From a real Windows in the Lakes project

Near Windermere, Cumbria · Whole-home glazing · windows, doors and rooflight

A Whole House, Front to Garden

Two elevations with opposite jobs. The front had to sit politely in an established street of tile-and-render houses; the back had to open a new extension almost entirely to the garden — while both read as one house, in one glazing language.

A single system family in two finishes: Georgian-bar steel-look casements in agate grey to the frontage, and a wide-span door and screen run in anthracite to the garden. Sightlines, bar widths and head heights were set out across the whole house as one drawing set, and the lantern was specified to match the extension frames so the roof glass belongs to the same scheme.

Read the project story

Next step

Considering aluminium windows for your own project?

We design, specify and install across Cumbria, the Lake District and the wider North. Send drawings, photographs or simply a description of the building and we will tell you what is possible and what it should cost.

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