Daimant is a family-run window installer based in Caerphilly, fitting replacement windows in homes across Caerphilly and Cardiff. This guide sets out what new windows cost using published price bands, broken down per window, by window type and by house type. It also covers what a fair quote should include, so you can budget before anyone visits.
- FENSA registered
- 10-year insurance-backed guarantee
- Fixed written quote
- Our own Caerphilly fitting team
Fitted by our own Caerphilly team
How much do replacement windows cost in Cardiff?
Replacement uPVC casement windows in Cardiff cost roughly £350 to £520 each, according to Checkatrade’s new windows guide (updated July 2026), and a three-bedroom house with about 12 casements comes to around £7,500 for the whole job. These are national guide figures, so treat them as a starting point for Cardiff and Caerphilly homes rather than a local quote. Size, glass and access all change the final price.
| What you are pricing | Checkatrade guide figure |
|---|---|
| One uPVC casement window | £350 to £520 |
| Three-bedroom house, about 12 casements | About £7,500 |
Daimant does not publish a price list. We survey your home for free and then give you a fixed written price, with no obligation to go ahead.
- Casement windows sit at the lower end of Checkatrade’s July 2026 bands.
- Sliding sash windows cost the most per opening.
- The number of windows in your house sets the total more than anything else.
- Daimant gives you a fixed written price after a free survey.
How does the cost change by window type?
Window type changes the price more than anything else on a quote, with Checkatrade putting uPVC casements at the lower end of its bands and uPVC sliding sash at the top. Every extra opening part, hinge and length of frame adds to the price. Our casement windows suit a wide range of house styles and sit at the lower end of these bands.
| Window type | Checkatrade band per window | Why it costs what it does |
|---|---|---|
| uPVC casement | £350 to £520 | Simple hinged sashes and the least frame per opening. |
| Flush sash | No separate band given | The sash sits flush inside the frame for a traditional look. We price flush sash windows on survey. |
| uPVC vertical sliding sash | £700 to £1,500 | Two sliding sashes, balances and more frame to make. |
| uPVC tilt and turn | £490 to £695, up to £810 by size | Dual action hardware that tilts in for air and turns in for cleaning. |
What does a whole house cost by house type?
Whole-house window cost follows the number and size of the openings, so a small terrace with six to eight windows comes in well below a detached home with ten to fourteen, even at the same price per window. The table below multiplies Checkatrade’s casement band by an example window count for each house type found across Cardiff and Caerphilly.
| House type | Example window count | Casement band × count | What tends to push it up |
|---|---|---|---|
| Terrace | 6 to 8 | £2,100 to £4,160 | Sash-style fronts, tight rear access, conservation area rules. |
| 1930s semi | 8 to 10 | £2,800 to £5,200 | Bay windows, which need more frame and more fitting time. |
| Detached | 10 to 14 | £3,500 to £7,280 | More large openings, upstairs access and mixed window types. |
Checkatrade’s whole-house example of about 12 casements for around £7,500 works out higher per window than its single-window band. Treat the arithmetic above as a floor, and count your own windows before you compare anything.
What goes into a window price?
A window price covers far more than the frame and glass, and a proper quote also includes taking out the old windows, making good around the new ones, sills, ventilation and the certificate that proves the work meets Building Regulations. Ask for each of these as its own line, so nothing is missing on fitting day.
- Removal and disposal: the fitter takes out the old frames without damaging the brickwork and takes them away.
- Making good: the fitter fills and finishes plaster, render and reveals around each new frame.
- Sills: a new sill goes in where the old one is cracked or does not suit the new frame depth.
- Trickle vents: these small vents in the frame head let background air in, and your installer should check them against the ventilation rules for your home.
- Glass specification: A+ rated double glazing is available, and the quote should name the rating.
- Certificate: the installer registers the job with FENSA, or another scheme such as CERTASS, after fitting.
Why can the cheapest quote fail Building Regulations?
The cheapest window quote can fail Building Regulations when the installer is not registered with a competent person scheme such as FENSA or CERTASS, because nobody then certifies that the new windows meet the Part L energy rules. Without it, you would need to apply to building control yourself and pay the fee.
The gap usually comes to light when you sell. Conveyancers ask for proof from FENSA or building control that replacement windows were signed off, and missing paperwork can delay a sale. Daimant is FENSA registered, so we register your windows and the certificate is issued in your name.
Can grants or finance reduce the cost?
Grants for double glazing in Wales are uncommon and usually come as one part of a wider energy package, so it is safer to budget for paying for replacement windows yourself. Nest, the Welsh Government’s Warm Homes programme, focuses on insulation and heating for qualifying households.
Our guide to grants for double glazing in Wales explains who qualifies and how to check. For spreading the cost, ask your surveyor about payment options on the day of your free survey.
How do you compare window quotes?
Window quotes compare fairly only when each one prices the same number of windows, the same opening styles and the same glass, and lists removal, making good, sills and the certificate as separate lines. A lower total can mean a smaller job rather than a better price.
Give every installer the same list
Count your windows and note which ones open, so each quote covers the same job.
Ask for an itemised quote
Check that removal, making good, sills and trickle vents each appear as a line.
Match the glass and security
Look for the glass rating and for PAS 24 or Secured by Design on each quote.
Check the certificate and guarantee
Ask who registers the work with FENSA or CERTASS and how long the guarantee runs. Daimant gives a 10-year guarantee, backed by insurance.
Get the price and timetable in writing
A fixed written price protects you from extras, and your surveyor gives you the timetable in writing too.
Do new windows pay back in energy savings?
New windows reduce heat loss through old single glazing or failed double glazing, but the payback period depends on what you are replacing, how you heat the house and where your EPC rating starts. For that reason, nobody can promise a fixed number of years. Our guide to EPC gains from new windows looks at how glazing affects your rating and your bills.
Which window type should you price?
The window type to price is the one that suits your house and the rules on your street: casements for a wide range of house styles, flush sash for a traditional look, vertical sliding sash for period fronts, and tilt and turn for easy cleaning. Street rules apply in both towns. Cardiff Council has 27 conservation areas, including Roath Park and Llandaff, and many have Article 4 Directions that control changes to windows. Caerphilly County Borough Council also designates conservation areas and publishes a map you can check.
The fastest way to firm up these bands is a survey, and our page of A-rated windows we fit shows the four types Daimant fits.
Frequently asked questions
Window sizes, types and access differ from house to house, so Daimant prices every job after a free survey. You get a fixed written quote with no obligation to go ahead.
Checkatrade’s July 2026 guide gives a whole-house figure for a three-bedroom home with about 12 uPVC casements, shown in the first table above. Bay windows, sash styles or larger openings raise that figure, and a survey gives you the exact number.
Yes. You can replace the front windows first and the rest later, and each stage is certified when it is fitted. Ask your surveyor to price the whole house and each stage so you can plan.
Windows in Cardiff conservation areas with an Article 4 Direction, such as parts of Roath Park or Llandaff, can need consent before they are changed. Check with Cardiff Council before you order, and listed buildings normally need listed building consent too.
A+ rated double glazing lets less heat escape than lower rated glass, and the difference in price varies by window. Ask your surveyor to price both options so you can see the gap in writing.
