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.
If you have replacement windows on your list for a property in Harrow, we can help from the first measurements to the final clean-up. For a typical home, plan for 1–2 days on site for a typical house, though larger or more complex jobs take longer. We cover postcodes HA1, HA2, HA3 and HA5 and nearby Wealdstone, Brent and Wembley, and every quote we send is fixed for the scope described in it.
- Guide price
- £5,800–£11,500 inc VAT
- Time on site
- 1–2 days on site for a typical house
- Postcodes
- HA1, HA2, HA3, HA5 and HA7
- Planning rules
- England
- Local area
- Greater London
- Survey
- Free, with a written quote
What should you budget for replacement windows in Harrow?
No two jobs cost exactly the same, but the ranges below give a fair picture of replacement windows in Harrow. Pricing for London runs about 30% above the national guide, and the overall guide is £5,800–£11,500 with VAT included. We'll confirm your figure after surveying the property for free.
| Type of job | What it usually involves | Guide in Harrow |
|---|---|---|
| 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 |
Your price depends mostly on:
- Frame material, colour and finish, inside and out
- Glazing type: double, triple, acoustic, obscure or toughened
- Window style, such as sash, flush sash or tilt-and-turn
- Upper-floor access, scaffolding and the condition of reveals and sills
Scope of the work
- 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
- Fixings, packers, foam and weather seals to suit your wall type
- New internal trims, external cills and neat sealant finishing
Local housing and replacement windows
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.
That variety is why a guide price for replacement windows in Harrow is only a starting point; the survey shows what your particular property needs.
Do you need permission in Harrow?
The notes below cover England, which is where Harrow sits. Rules change and every property is different, so we speak to the council before pricing your job.
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.
The four stages
A visit to your home
It starts with a survey at the property, free of charge. We check condition, access and services, ask how you want the finished result to look, and answer any questions you have about replacement windows.
Price and scope agreed
We put everything into a written, fixed-price quote: the specification, what's excluded, staged payments and the expected time on site. Take whatever time you need to decide; there's no pressure to commit.
Booking the work
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Harrow property.
On site to finish
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
Why homeowners choose us
Replacement windows in Harrow: questions
How long does it take to fit windows in a house?
Fitting replacement windows in a typical 3-bed house usually takes one to two days on site. We take out and fit one window at a time, so each room is weathertight again within an hour or two. Bays, sash windows and homes needing scaffolding take longer. Manufacture comes first: made-to-measure frames typically take a few weeks to arrive after the survey and your order are confirmed.
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.
Is triple glazing worth paying extra for?
Triple glazing adds a third pane of glass, which cuts heat loss and outside noise further than standard double glazing. It typically adds around a third to the cost of the glass units and makes opening sashes heavier. It makes most sense on cold or noisy elevations, or in homes being upgraded to a high energy standard. For many houses, modern double glazing with a warm edge spacer gives most of the benefit for less money.
Do you cover Wealdstone, Brent and Wembley?
Yes. As well as Harrow, we cover Wealdstone, Brent and Wembley and the rest of London. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
How long will replacement windows take?
On a typical home, allow 1–2 days on site for a typical house. Larger projects, older buildings and extra work found once things are opened up can extend that, while simpler jobs may be shorter. Your quote includes an estimate of time on site, and your point of contact keeps you updated on the programme as the work progresses.
Also covering areas around Harrow
Live in Harrow? Our coverage takes in the HA1, HA2, HA3 and HA5 postcode areas and reaches out to Wealdstone, Brent and Wembley, so homes on the outskirts and in the next town along are included.