Double glazing quotes in Cardiff
Compare free written quotes from local installers who cover your CF postcode, for replacement windows, sash and bay windows, sealed units and repairs. Cardiff is wet and faces the Severn Estuary, so ask every installer how their windows keep the weather out.
Cardiff averaged 1,201 mm of rain a year, 1991 to 2020 (Met Office)
- Local installers who cover your Cardiff postcode
- Quotes to the Welsh standard: U-value 1.4 or WER band B
- Free and no obligation. You decide whether any quote goes ahead
How it works
How to get double glazing quotes in Cardiff
One short form, then written quotes from local installers.
Answer six questions
Property type, window count, frame material and when you want the work done. It takes about a minute.
Take one call
A quick call confirms the job, then it goes to local installers who cover your CF postcode.
Compare the specs
Check every written quote for the WER or U-value, the BS 6375-1 classes and the FENSA or CERTASS scheme.
What installers quote for
What can you get quoted for in Cardiff?
Cardiff quotes cover replacement windows in uPVC, aluminium and timber, plus sash and bay windows on the city's older streets. Say which of these you want on the confirmation call:
- Full replacement windows: casement, tilt and turn, bay and sash, in uPVC, aluminium or timber
- Glass-only replacement: new sealed units for misted or cracked panes in sound frames
- Repairs: hinges, handles, locks and seals on windows that are otherwise sound
- Doors: composite, uPVC and patio doors, so ask the installer whether they fit them
Name the material and style you want on the form, so every installer prices the same job. Sash fronts have their own guide to sash window replacement.
Get Cardiff window quotesFree, no obligation
Local factors
What changes a Cardiff double glazing quote
Six things change a Cardiff double glazing quote: rain, the Welsh U-value limit, scheme sign-off, the age of the house, its energy rating and listed or conservation status. Settle each one before the survey.
| In Cardiff | What it changes in your quote | Ask or check |
|---|---|---|
| 1,201 mm of rain a yearMet Office, 1991 to 2020 | Frames need stated weather classes | BS 6375-1 classes and sill drainage |
| U-value 1.4 or WER band BApproved Document L, Wales | The standard every replacement window must reach | The figure for each window |
| FENSA and CERTASS operate in WalesFENSA | A registered installer self-certifies the job | Registration on the scheme's website |
| 17.8% of properties built before 1900VOA | Bay fronts and sashes on older streets | Each bay priced as one line |
| About a quarter of pre-1929 homes reach EPC CONS | Older homes gain most from new glazing | A sash-style option next to casements |
| 871 listed buildings and 27 conservation areasCadw, Cardiff Council | Consent for listed window changes | Who prepares consent drawings |
Weather
Window quotes built for Cardiff rain
Cardiff windows need a stated weathertightness rating, because the Met Office Cardiff station averaged 1,201 mm of rain a year from 1991 to 2020. That is roughly double the 616 mm at London Heathrow over the same years, and the Severn Estuary frontage adds wind and salt. BS 6375-1 is the UK standard that classifies a window's air permeability, watertightness and wind resistance. Ask each Cardiff installer for:
- the BS 6375-1 watertightness and wind resistance classes of the windows quoted
- the sill and drainage detail at the bottom of each frame
- hardware and finishes rated for coastal use, if your home faces the estuary
Get weather-rated window quotesFree, no obligation
Welsh building regulations
What Welsh building regulations mean for a Cardiff quote
Replacement windows in Cardiff must reach a U-value of 1.4 or a Window Energy Rating of band B. That limit is in Table 10.1 of Approved Document L volume 1 for Wales, in force since 23 November 2022. The 2026 Welsh edition takes effect on 4 March 2027 and keeps the same figure.
Wales writes its own Approved Documents, so a Cardiff quote is specified to the Welsh document, not the English one.
Who signs off the work
FENSA and CERTASS both operate in Wales. FENSA describes its scheme as covering "window and door replacements across England and Wales", so a registered Cardiff installer self-certifies the job and registers it. Ask which scheme each installer belongs to, then check the registration on the scheme's own website before you sign.
Get quotes to the Welsh standardFree, no obligation
Older homes
Replacement windows for Victorian Cardiff homes
Close to one Cardiff home in five predates 1900. The Valuation Office Agency puts 17.8% of Cardiff properties before 1900 and 23.7% before 1919 (Council Tax stock of properties, 31 March 2026).
Those older homes lag on efficiency. ONS EPC data shows about a quarter of Cardiff's pre-1929 homes with an EPC reach band C or above, against 58.5% of all Cardiff homes with an EPC. Bay fronts and sashes on these streets are where a glazing upgrade moves the rating most.
Ask installers to price each bay as one line and to offer a sash-style option alongside casements. Check whether your frontage sits in a conservation area before you pick a style.
Get bay and sash window quotesFree, no obligation
Heritage
Window quotes for listed and conservation-area homes in Cardiff
Cardiff has 871 listed buildings on Cadw's list (17 grade I, 41 grade II*, 812 grade II) and 27 conservation areas, according to Cardiff Council. Window changes on a listed building need listed building consent, so confirm the status with the council before you invite quotes.
Ask any installer who quotes for a listed or conservation-area frontage for photos of similar Cardiff jobs, and for who prepares the consent drawings.
Get Cardiff heritage window quotesFree, no obligation
Repair or replace
Repair, replace or a cheaper alternative for Cardiff windows?
Repair a Cardiff window when the frame is sound and only the glass, seal or hardware has failed. Replace it when the frame is rotten, warped or lets rain into the wall below. A misted pane means the seal of the sealed unit has failed, and a new unit fits into a sound frame without a new window.
Damp plaster under a sill or water on the inside of the frame points to a frame or drainage fault, and new glass does not fix either. Ask the installer to say in writing which of the two it is.
Period frontages have a third option. Cardiff Council publishes a list of joiners who repair and reproduce traditional timber windows and doors, which suits listed and conservation-area homes where replacement needs consent. Secondary glazing is the fourth route: an inner pane fitted behind the existing window, which stays in place.
Get repair or glass-only quotesFree, no obligation
Before you sign
How to choose a double glazing company in Cardiff
Choose a Cardiff double glazing company in six steps: scheme registration, company history, the guarantee, who fits, matching written quotes and the right questions at the survey.
- Find the company on FENSA's installer search or the CERTASS register yourself, not from a logo on its van or website.
- Look it up on Companies House to see whether it is active, when it was incorporated and any earlier names.
- Ask for the guarantee in writing, and whether it is insurance-backed so it survives the company closing.
- Ask whether its own fitters do the work, and visit the showroom or a fitted Cardiff job to see the product quoted.
- Get three written quotes for the same windows, glass and BS 6375-1 classes, then line them up with our guide on how to compare double glazing quotes.
- Take our list of questions to ask a double glazing salesman to each survey.
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 double glazing cooling-off period guide explains why. Timing matters too: see the best time to buy double glazing.
Areas
Cardiff areas this page covers
This page is about homes across the Cardiff council area and the edge of the Vale of Glamorgan, in the CF postcode districts below. Enter your postcode in the form and the confirmation call tells you whether a local installer covers it.
| Postcode district | Places |
|---|---|
| CF10, CF11 | City centre, Butetown, Cardiff Bay, Grangetown, Canton |
| CF24 | Cathays, Roath, Plasnewydd, Splott, Adamsdown |
| CF5 | Llandaff, Ely, Caerau, Fairwater, Danescourt, Riverside |
| CF14 | Whitchurch, Rhiwbina, Heath, Llanishen, Gabalfa, Thornhill, Lisvane |
| CF23 | Cyncoed, Penylan, Pentwyn, Pontprennau |
| CF3 | Rumney, Llanrumney, Trowbridge, St Mellons |
| CF15 | Radyr, Morganstown, Pentyrch, Creigiau, Tongwynlais |
| CF64 | Penarth, Sully, Llandough |
Near Cardiff, see double glazing quotes in Swansea or, over the Severn, double glazing quotes in Bristol.
Related guides
FAQ
Cardiff double glazing questions
Who will contact me after I ask for quotes?
You get a quick call to confirm the job, then it goes to local installers who cover your postcode, and those installers contact you to arrange a survey and a written quote.
Are there any grants for double glazing in Wales?
Windows are not on the list of improvements on the home page of Nest, the Welsh Government's Warm Homes scheme, which lists heat pumps, insulation, solar panels and heating repairs. Check the current list on nest.gov.wales before you rely on a grant.
What energy rating do new windows need in Cardiff?
New and replacement windows in Cardiff need a U-value of 1.4 or a Window Energy Rating of band B, under Approved Document L for Wales.
Do Cardiff installers give a FENSA certificate?
Yes, a FENSA-registered installer issues one, because FENSA covers England and Wales. A CERTASS-registered installer issues an equivalent certificate. Check the installer's registration on the scheme's website.
Which double glazing company is considered the best in the UK?
No single company is best for every home. The right one for a Cardiff home is FENSA or CERTASS registered, gives a written insurance-backed guarantee and quotes the same spec as the others.
Can I get a quote for misted glass only in Cardiff?
Yes, ask for a glass-only quote, because a new sealed unit fits into a sound frame. Say "misted units" on the confirmation call, and ask each installer to price glass only and full replacement separately.
Is it worth replacing 20 year old double glazing?
Replacing 20-year-old double glazing is worth it when the frame is rotten, warped or lets rain into the wall; a misted unit in a sound frame needs only new glass. Any new window in Cardiff must reach a U-value of 1.4 or WER band B, so ask for that figure next to a glass-only price.
Is there a cheaper alternative to double glazing?
Secondary glazing, new sealed units and repairs are the usual alternatives to new double glazed windows. Secondary glazing adds an inner pane and keeps the existing window, which suits listed and conservation-area homes. Ask installers to price each option next to replacement.
What are the disadvantages of double glazing?
The main disadvantages of double glazing are the up-front cost, sealed units that mist when their seal fails, and frames that let rain in when the sill and drainage are poorly detailed. With Cardiff averaging 1,201 mm of rain a year, ask for the BS 6375-1 watertightness class on every quote.
How much should I expect to pay for double glazing?
Prices depend on the window count, material and glass on your written quotes, and our sister site sets out what double glazing costs in Cardiff.
Get Cardiff quotes built for wet weather
Ask for the same spec from every installer and compare the weather ratings side by side. Read how to choose a double glazing installer, or compare double glazing quotes anywhere in the UK.
Get free Cardiff quotes
Sources
- Met Office, Cardiff historic station data: metoffice.gov.uk; Heathrow: metoffice.gov.uk (1991 to 2020 averages computed from complete years)
- Welsh Government, Approved Document L volume 1 (2022 edition incorporating 2024 amendments), Table 10.1: gov.wales
- Welsh Government, Approved Document L volume 1, 2026 edition: gov.wales
- FENSA, About FENSA: fensa.org.uk
- VOA, Council Tax: stock of properties 2026, table CTSOP4.1: gov.uk
- ONS, EPC band C or above, England and Wales, tables 2a and 2c: ons.gov.uk
- Cadw listed buildings via DataMapWales: datamap.gov.wales
- Cardiff Council, conservation areas: cardiff.gov.uk
- Cardiff Council, repair and reproduction of windows and doors: cardiff.gov.uk
- FENSA, find an installer; CERTASS: certass.co.uk; Companies House: company search
- CF postcode districts and places: CF postcode area (read 1 October 2026)
- Postcode districts: postcodes.io outcode lookup (ONS Postcode Directory), checked 2026-10-02
- Nest (Welsh Government Warm Homes): nest.gov.wales