How long do new windows typically last?

UPVC windows are generally rated for 20–30 years, though many last longer with minimal maintenance. Timber windows can last 40+ years if regularly maintained (repainting every 5–7 years). Aluminium sits somewhere in between at 25–35 years. The sealed unit (the glass and spacer bar inside) typically lasts 10–20 years before the seal fails and condensation appears between the panes. A good fitter will fit units with a 10-year guarantee as standard. Real longevity depends on maintenance, exposure to weather, and whether the frames were fitted correctly in the first place — poor fitting causes premature failure.

What's the difference between double and triple glazing?

Double glazing has two panes of glass with a gap filled with argon or air. Triple glazing adds a third pane. Triple is better for insulation and noise reduction but costs 20–40% more and is heavier, so frames must be robust. In Cardiff's climate, double glazing is usually sufficient for most homes. You'll only see real benefit from triple in exposed locations, listed buildings where you want the best performance, or if you're very sensitive to noise. Check your EPC (Energy Performance Certificate) — it'll suggest what grade of glazing is cost-effective for your property. A good fitter can model the difference and give you payback timescales based on heating savings.

Do I need Building Regulations approval for window replacement?

Yes. Any window replacement must meet current Building Regulations, even if the original windows didn't. A FENSA or Certass registered fitter handles this — they'll certify the work meets standards and provide a certificate. If you use an unregistered fitter, you'll need to notify your local council's Building Control department and arrange an inspection (costs £200–£400). Don't skip this: it's a legal requirement, and you'll need the certificate when you sell the house. Most modern replacement windows (UPVC, aluminium, timber with decent U-values) meet regulations easily, so it's rarely a barrier — it's just a paper trail that protects you.

How do I know if my window fitter is reliable?

Check accreditation (FENSA or Certass), ask for references and ring them, verify they're insured, and ask how long they've been fitting windows. A fitter with 10+ years' experience in Cardiff will know the local housing quirks. Read online reviews but take them with a pinch of salt — angry customers shout loudest. Watch during the site visit: do they take time to measure and understand your home, or do they rush? Do they explain what they're doing? A chatty, patient fitter usually does good work. Finally, get everything in writing and check their warranty is clear and unconditional. If something feels off during the consultation, trust your gut — there's no shortage of fitters.

What should I do if windows fail shortly after fitting?

Contact the fitter in writing (email is best — keeps a record) and describe the fault: condensation between panes, rattling, draughts, water ingress, misalignment. A reputable fitter will come back and fix defects within the warranty period (usually 10 years on the sealed unit, lifetime on the frame labour). If they refuse or disappear, contact their accreditation scheme (FENSA or Certass). These schemes have dispute resolution processes and can take action against rogue traders. In extreme cases, you can pursue small claims court or contact Citizens Advice Consumer Service. This is why accreditation matters — it gives you a safety net. Always keep your paperwork (quote, invoice, warranty certificate, FENSA certificate) and photograph any defects as evidence.

Cardiff window fitters 2026 — Costs, Free Quotes, Vetted Pros

What Window Fitters Do and Why You Need One

A window fitter installs new windows, replaces old ones, and handles repairs that go beyond a quick fix. They measure openings, prepare frames, fit units square and level, seal gaps, and make sure everything operates smoothly. It's skilled work — get it wrong and you'll have draughts, condensation, or water ingress for years.

Whether you're replacing single-glazed timber frames with modern double or triple glazing, or fitting new units into an older Cardiff terraced house, a proper fitter makes the difference between a job that lasts 20 years and one that causes headaches within five.

You might think window fitting sounds straightforward, but there's more to it than sliding a unit into a hole. Fitters need to understand building regulations, damp management, thermal bridging, and the specific quirks of older Welsh properties — many Cardiff homes have solid walls, uneven openings, or heritage considerations that demand experience.

This guide walks you through what to expect, how much you'll pay, what accreditations matter, and the right questions to ask before you hire.

What Window Fitting Costs in Cardiff Right Now

Prices vary wildly depending on window type, frame material, and how many you're replacing. Here's what you're realistically looking at in 2026:

Single window replacement (UPVC, double-glazed): £300–£600 fitted. This covers a standard casement or sash-style window, 1200mm × 1200mm, including frame preparation and sealing.

Timber sash windows (like period-appropriate replacements for Victorian terraces): £500–£1,200 per window. These take longer to fit and often need careful frame repair or matching.

Aluminium frames (premium modern finish): £400–£800 per unit. More expensive than UPVC but better-looking and thermally superior.

Full house replacement (10–15 windows, mixed sizes): £4,500–£9,000. Costs depend heavily on property age, whether frames need rebuilding, and whether you want triple glazing.

Call-out for repairs or adjustments: £80–£150 for a surveyor visit, sometimes waived if you proceed with work.

Labour typically sits at £150–£250 per day, though most fitters quote fixed prices per window rather than day rates. Always ask whether the quote includes:

Removal and disposal of old frames
Making good internal plaster or plasterboard
External brickwork pointing
Sealing and draught-proofing
VAT (20%)

Don't assume the cheapest quote is best. A fitter working at £200 a window might be cutting corners on sealing or insulation. Mid-range quotes from accredited fitters usually offer better value.

Accreditations That Actually Matter

Two accreditations stand out in the UK window fitting world: FENSA and Certass. Both are legitimate, so don't panic if a fitter holds one and not the other — but they do different things.

FENSA (Fenestration Self-Assessment Scheme): This is the most common. FENSA-registered fitters can self-certify their work meets Building Regulations. That means they issue a FENSA certificate after the job, which is a legal document proving compliance. It's valuable when you sell — buyers and mortgage lenders want evidence that windows were fitted to standard. FENSA covers UPVC, timber, and aluminium. There's a small admin fee (usually £15–£20 per window) added to your invoice.

Certass (Certification of Fenestration Installations): Similar to FENSA but less common in Wales. Both schemes require fitters to be trained, insured, and inspected regularly. Either one is fine.

Why it matters: If a fitter can't offer either, ask why. Some older independent fitters work to Building Regulations but aren't registered — this is riskier for you because you'll need to organise a Building Control inspection yourself (costs £200–£400). Stick with registered fitters unless you have a very good reason not to.

Other badges: Look for Gas Safe or OFTEC if the fitter also handles heating (less relevant here), and check they're insured for public liability (minimum £1 million) and provide a written guarantee (usually 10 years on sealed units, longer on frames).

Cardiff Housing and Window-Fitting Specifics

Cardiff's housing stock is a mixed bag, and it matters for window fitting.

Much of the city — Cathays, Canton, Roath — consists of Victorian and Edwardian terraced homes. These properties have solid stone or brick walls, often with shallow reveal depths (the space between the outer wall and inner face). Standard modern windows might not fit without adapting the reveal, which adds cost. Many fitters know this; some don't. Ask a local fitter whether they've worked on period terraces before.

Older Cardiff homes frequently suffer from damp issues, especially in ground-floor rooms and basements. Poor window installation can make this worse if moisture paths aren't properly sealed during fit. A good fitter will understand moisture management and use appropriate expanding foam and sealants, not just grab whatever's nearest.

The city's exposed hillside areas — places like Llandaff and Cyncoed — see higher wind speeds. UPVC frames can rattle or flex in strong weather if they're not fitted rigidly. Timber and aluminium are often more stable in these locations, though they cost more.

Building Regulations in Wales are devolved, meaning Cardiff follows Welsh Building Standards. They're broadly similar to England's but differ on detail. A FENSA-registered fitter will know the local rules; an unaccredited one might not.

Finally, Cardiff's Welsh heritage means some properties are listed or sit in conservation areas. Listed building consent is needed for window changes — a good fitter will flag this and help you navigate the process, but it's not their job to apply. Check with Cardiff Council's conservation team first if you're unsure.

How to Find and Hire a Window Fitter

Start by asking for recommendations. Word-of-mouth from neighbours or friends is gold — they'll tell you honestly if someone was slow, messy, or left gaps.

Use trade directories like Best Trades Wales to find local, registered fitters. Filter by location and check accreditations. Read any reviews (though always assume some exaggeration either way).

Once you've got a shortlist of three to five, contact them. A good fitter will:

Offer a free site visit and quotation
Take measurements themselves (don't rely on you guessing)
Explain what they're doing and why
Give you a written quote with itemised breakdown
Provide proof of accreditation and insurance
Offer a warranty in writing

Don't book the cheapest. Compare what's included. One quote at £4,000 might include removal, making good, and triple glazing; another at £3,500 might only cover the units themselves.

Once you've chosen, get everything in writing: start date, finish date, total cost, payment terms, warranty, and what happens if something goes wrong. Most fitters want a deposit (usually 25–50%) upfront and the balance on completion.

Before work starts, check the fitter has buildings insurance and that their FENSA or Certass registration is current — you can verify online through the scheme's website. This takes five minutes and saves headaches later.

Eight Questions to Ask Before You Hire

Ask these questions before committing to a fitter:

1. Are you FENSA or Certass registered? Get their registration number and verify it online.

2. What's included in your price? Old frame removal? Making good plaster? External pointing? Disposal? Be specific.

3. How long will the job take? Single window should take 2–4 hours. A full house might be 5–10 days depending on scope.

4. What warranty do you offer? Push for 10 years minimum on sealed units and frames, and get it in writing.

5. Can you provide references? Ask for the names and phone numbers of recent clients — and actually ring them.

6. What happens if there's a problem after completion? Will they come back and fix it? Who pays?

7. Do you have public liability insurance? Ask to see the certificate.

8. Will you apply for Building Control certification (or FENSA certificate)? This is essential for compliance — some fitters charge extra, others include it.

If a fitter gets evasive on any of these, walk away. The right person will answer clearly and confidently.