Get free quotes
Nine checks before anyone quotes

Double glazing installers: how to choose and check one

Choose double glazing installers on nine checks: scheme registration, years trading, past work, reviews, the survey, a written quote, the guarantee, a dispute scheme and no pressure to sign. Then compare free written quotes from local installers who cover your postcode.

  • Postcode first. Your enquiry goes to installers who cover your area
  • Nine checks to run on every installer before you sign
  • Free and no obligation. Say no to every quote if none suit you

We are a free quote-matching service, not an installer.

Step 1 of 7Your property
What type of property is it?

This sets a typical window count. You can change it next.

How many windows need replacing?

Count each opening once. A bay counts as one.

10

windows

Which frame material?

Not sure? uPVC is what most UK homes fit.

When would you like them fitted?

This helps installers plan your survey visit.

Do you own the property?

Installers can only fit windows with the owner's agreement.

What's the property postcode?

We match you with installers who cover it.

Where should we send your quotes?

You will get a quick call to confirm the details, then local installers who cover your postcode get in touch.

First line only, for example 12 Mill Lane. We already have your postcode.

Thanks , your enquiry is on its way

Here is exactly what happens now, so nothing arrives unannounced.

  1. You get a call to confirm your requirements. This is usually the first call you get, so keep your phone handy.
  2. Local installers who cover your postcode then phone you to arrange quotes.
  3. You compare and decide. There is no obligation to accept any quote. Our quote comparison guide shows how to check them line by line.

Changed your mind? Email hello@doubleglazingquote.uk to withdraw. The privacy policy has the detail.

Free No obligation

Nine checks

How do I choose a good double glazing company?

Choose a company registered with FENSA or CERTASS that shows you past work, surveys every window and puts the full specification and guarantee in a written quote. Run these nine checks on each firm:

  1. Scheme registration: FENSA or CERTASS, confirmed on the scheme's own register (steps below). Both are on the GOV.UK list of competent person schemes.
  2. Years trading: Which? suggests a company trading for 10 years or more. Check Companies House for name changes or a past liquidation.
  3. Past work you can see: addresses or photos of jobs like yours. Period homes need sash experience, so see sash window replacement for those.
  4. Independent reviews: read on platforms the installer does not control.
  5. A proper survey: every opening measured and the structure around it checked, before any price is final.
  6. An itemised written quote: every window priced on the same specification as the other quotes, not a single total.
  7. An insurance-backed guarantee: named in writing, with its length.
  8. A dispute resolution scheme: membership of an alternative dispute resolution (ADR) scheme. Which? names DGCOS as one example.
  9. No pressure: no "sign today" price and no cold calling. Which? advises never to use a cold caller.

To line the quotes up once they arrive, use our guide on how to compare double glazing quotes.

Step by step

How to check an installer is FENSA or CERTASS registered

Check an installer's registration on the scheme's own search before the survey, in five steps. It takes a few minutes, and we do not do it for you.

  1. Ask which scheme. Get the scheme name and registration number in writing, on the quote.
  2. Search FENSA. Open the FENSA installer search and enter your postcode, the installer's name or the FENSA registration number.
  3. Search CERTASS. CERTASS sends homeowners to Certified Competent, which searches by company name or postcode.
  4. Match the company. The name and address on the register match the company on your quote and contract. Then look the company up on Companies House for its age, past names and any liquidation.
  5. Get the certificate. After fitting, the installer registers the job, and FENSA usually sends the certificate within 15 days. Keep it: FENSA says it is often needed when you sell or remortgage.

What FENSA does not cover

FENSA registers replacement windows and doors in existing homes in England and Wales, fitted in the original opening without widening it. Its Help Centre lists work it cannot register, including:

  • new conservatories, extensions and new builds
  • repairs where the frame is not included
  • Grade I listed properties

For those jobs, ask your council's building control team how the work is signed off. Scotland follows its own building standards. For a repair that keeps the frame, our page on Manchester window replacement shows which faults need only new glass or hardware.

No FENSA certificate for your windows?

Search by address on FENSA's find and order your FENSA certificate page. FENSA gives two common reasons a job is missing: the installer was not FENSA approved at the time, or did not notify FENSA. Work by an unregistered installer needs building control approval from your council instead.

Local pages

Double glazing installers by area

Each local page leads with what changes a window quote in that area, such as conservation areas, Article 4 directions and the age of the housing. Pick yours, or use the form above with any postcode. Own a flat? Read our guide to replacing windows in a leasehold flat before any installer visits.

England

Counties and towns

London areas

Scotland and Wales

Trade directories such as Checkatrade, TrustATrader and Yell list installers for you to contact yourself. Whichever route you use, run the FENSA or CERTASS check above on every installer.

At your home

What a proper double glazing survey covers

A proper double glazing survey covers five things before the installer puts a price in writing, according to Which?:

  1. Measurements: every opening measured, not estimated from the outside.
  2. Structure: the walls and openings checked for anything that changes the job.
  3. Specification: frame material, glass, opening style and finish agreed per window.
  4. Practical issues: access, upper floors and anything that needs extra labour or equipment.
  5. Your questions: time to ask about the product, the fitting and the paperwork.

A quote given without a survey is an estimate. Take our list of questions to ask a double glazing salesman to every survey.

Sales tactics to walk away from

  • "This price is only good if you sign today"
  • A large "discount" off an inflated list price
  • A request for a large deposit before anything is made
  • A single total with no breakdown per window
  • No written information about your right to cancel
  • Cold calls and unannounced doorstep visits

Before you pay anything, read our guide on how much deposit to pay for double glazing.

Who quotes

Local, regional or national installers

Local firms, regional firms and national brands all quote for replacement windows, and FENSA's approved installers range from large national brands to small local companies. The same nine checks apply to all three. What changes is what you ask.

Installer typeAsk before the survey
Local independent installerWho fits the windows: the owner, employed fitters or subcontractors? Who handles a fault after fitting?
Regional firmIs your postcode inside their normal fitting area? Where are the frames made?
National brandIs the price on the day the same price in writing a week later? Who is the contract with: the brand or a local franchise?
 Ask every installer type for an itemised written quote on the same specification, so the prices compare like for like.

Who is the best double glazing company?

No single double glazing company is best for every home. Ask a local firm and a national brand to quote the same windows, glass and guarantee, then pick on the written quotes and the nine checks. A firm's guarantee also depends on the firm surviving, which our guide on what happens if your double glazing company goes bust explains.

Before you sign

Questions to ask an installer before you sign

Ask five questions of every installer, and get each answer in writing on the quote:

  1. Which scheme are you registered with, and under what number?
  2. Is the guarantee insurance-backed, and for how many years?
  3. What is the U-value or Window Energy Rating of each window?
  4. How much deposit do you take, and when are the payment stages?
  5. Where is the written information about my right to cancel?

Then work through our double glazing contract checklist line by line before you sign.

Cancelling after you sign

If you sign at home, you usually have at least 14 days to cancel, but made-to-measure windows can be an exception, so check the contract before you sign. Our guide to the double glazing cooling off period explains the rules.

How it works

How our installer matching works

You fill in one form, a quick call confirms the job, and local installers who cover your postcode survey and quote in writing. We are not an installer and we do not check installers, and the double glazing quotes service is free to use.

  1. Woman filling in an online form on her laptop

    Tell us about the job

    Property type, how many windows, frame material and when you want them fitted. It takes about a minute.

  2. Smiling man taking a phone call at home

    We confirm the details

    A quick call checks what you need, then your enquiry goes to local installers who cover your postcode.

  3. Fitter installing a white uPVC window frame

    Compare like for like

    Each installer surveys and quotes in writing. Check every quote against our quote comparison checklist before you sign anything.

Related pages

Best time of year to buy double glazing

Before the first survey: lead times and when to book the visits.

Read the guide

Window replacement London

How to check a London window fitter, and when a repair beats a new window.

See London quotes

FAQ

Double glazing installers: common questions

For timing, contracts and your rights, see our double glazing buying advice.

Do double glazing installers need to be FENSA registered?

FENSA or CERTASS registration decides who signs the work off. A registered installer self-certifies the work and you get a certificate. An unregistered installer's job needs building control approval from your council instead.

How do I find double glazing installers near me?

Enter your postcode in the form above, and your enquiry goes to local installers who cover it. To find FENSA registered installers near you yourself, search the FENSA installer search by postcode. Ask every installer where its fitters are based.

How many installers should quote?

Three installers quoting the same specification give you a fair comparison. One quote gives you nothing to compare against. Ask each one for the same windows, frame material and glass so the totals line up.

Are national double glazing companies dearer than local ones?

Compare the itemised written quotes, not the type of company. Ask a national firm and a local installer to price the same windows, glass and guarantee, then compare line by line.

How much does it cost to get double glazing installed?

Installers set their own prices after a survey, so get written quotes for your windows. For typical fitted prices, see what double glazing costs on our sister site.

Get quotes from local double glazing installers

Enter your postcode, take one call to confirm the job, then run the nine checks on the written quotes from installers who cover your area.

Get free quotes
Window fitter drilling a new frame into place

Sources

Get free quotes