Replacement windows are new frames and sealed double- or triple-glazed units fitted into your existing openings after the old windows are taken out, improving warmth, security and noise reduction while meeting current building regulations.
Anyone planning replacement windows in Westminster wants three things: a clear price, a realistic timetable and a tidy job. We publish a guide of £5,800–£11,500 including VAT for London up front, explain that work normally takes 1–2 days on site for a typical house, and confirm both in writing after a free survey of your property.
- Guide price
- £5,800–£11,500 inc VAT
- Time on site
- 1–2 days on site for a typical house
- Postcodes
- SW1, SW1A, SW1E, SW1H and SW1P
- Planning rules
- England
- Local area
- London
- Survey
- Free, with a written quote
How much do replacement windows cost in Westminster?
The table below shows guide prices for replacement windows in Westminster. They are based on rates in London, which run about 30% above the national guide, giving an overall range of £5,800–£11,500. All figures include VAT and are firmed up after a free site survey.
| Type of job | What it usually involves | Guide in Westminster |
|---|---|---|
| One to three windows | Replacing a few problem windows, such as a bay or a rotten kitchen window, in uPVC. | £900–£3,900 |
| Whole house in uPVC | Eight to ten standard uPVC casement windows on a typical 3-bed semi, fitted and finished. | £5,800–£9,800 |
| Whole house in aluminium or flush sash | Premium frames, colours or period styles across a typical 3-bed home. | £9,800–£18,000 |
What moves the price up or down:
- Number and size of windows, including bays and large picture windows
- Frame material, colour and finish, inside and out
- Window style, such as sash, flush sash or tilt-and-turn
- Upper-floor access, scaffolding and the condition of reveals and sills
What does the job include in Westminster?
- Measured survey of every opening, with sizes checked before manufacture
- Made-to-measure frames in your chosen material, colour and style
- Double-glazed units as standard, with triple glazing as an option
- Careful removal and disposal of the old frames and glass
- Trickle vents, escape hinges and safety glass where regulations require
- Building regulations sign-off arranged and paperwork handed over
Building in Westminster
London's housing is dominated by Victorian and Edwardian terraces, often in yellow London stock brick, with Georgian terraces in central districts and mansion blocks across many inner areas. Outer boroughs have large belts of interwar semis, and there are extensive post-war council estates. Many houses have been split into flats, and conservation areas are widespread.
London Clay shrinks and swells with the seasons, and street trees close to houses can contribute to movement, which affects foundation design.
Knowing the typical building types in London helps, but a survey of your own home in Westminster is what decides the right approach to replacement windows.
Do you need permission in Westminster?
Which rules apply depends on where you live. For Westminster, the answer is England, and the points below reflect that; we verify them with the council before quoting.
Replacing windows and doors on a house is usually permitted development in England when the new ones look broadly similar to the old. Flats, listed buildings and homes covered by an Article 4 direction can need consent, and conservation areas may limit materials or styles.
Replacement windows and external doors must meet Building Regulations for energy efficiency, ventilation and, on upper floors, escape. The work is either self-certified by an installer registered with a competent person scheme or signed off by building control.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
How does the job run?
A visit to your home
A free survey comes first. It gives us what we need to price replacement windows properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Price and scope agreed
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Plan and prepare
Once you accept, we agree start dates, order materials and deal with any planning, building control or neighbour notices the job needs. You'll know who is coming and when before work begins.
On site to finish
The job proceeds in the order set out in the programme, with dust and debris kept under control. Finally we tidy away, inspect the work together and pass the finished project over to you with its paperwork.
How we work
Frequently asked questions
How do I look after new uPVC or aluminium windows?
Caring for new windows is simple: wash frames and glass with warm soapy water a few times a year, avoiding abrasive cleaners and solvents. Clear the drainage slots at the bottom of the frame so rainwater can escape, and put a drop of light oil on hinges and locking points once a year. Check seals and the sealant around the outside every few years, and replace any that have cracked or shrunk.
Can I stay at home during the work?
In most cases, yes. Most people can live at home throughout, and we plan the work to keep disruption down by protecting floors, agreeing working hours and keeping access routes clear. Bigger jobs affecting kitchens, bathrooms or heating may mean a short spell with reduced facilities, and we talk this through with you at the survey.
Do I need planning permission for new windows?
Planning permission is not usually needed to replace windows with similar ones, but it depends on the size and style of the change, your home's location, whether it is listed or in a conservation area, and which UK nation you live in. Listed buildings normally need consent for any change, and some conservation areas restrict uPVC or new styles. Flats may also need the building owner's approval. We check the position for your property before quoting.
How much do replacement windows cost?
Replacement windows for a typical 3-bed semi cost £5,800–£11,500, depending on the number of windows, frame material and glazing. A single standard uPVC casement usually works out at roughly £500–£950 fitted, while aluminium, flush sash and sliding sash styles cost more. Bays, large panes and upstairs access add to the price. We measure every opening during the survey and give you a fixed price for the agreed specification.
What happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from replacement windows, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
Also covering areas around Westminster
We cover every part of Westminster, including SW1, SW1A, SW1E and SW1H, and nearby Pimlico, Soho and Chelsea. Wherever you are within that patch, the survey is free and the quote comes to you in writing.