How long do replacement windows typically last?

Modern uPVC windows last 25–35 years if maintained properly. Composite doors last 30+ years. Timber requires more care — with good maintenance (repainting every 5–7 years), they last 40+ years; neglected timber fails in 15–20. Sealed units (the glass part) typically fail around 15–20 years, though some last longer. The frame usually outlasts the glass. In Cardiff's damp climate, regular maintenance matters more. Poor ventilation or condensation issues will shorten lifespan. When a sealed unit fogs up (moisture between panes), that glass needs replacing — usually £150–£300 per pane — but the frame is often fine. A decent trader will replace just the glass and seal rather than the whole window.

What's the difference between double glazing and triple glazing in Wales?

Double glazing (two panes with an air gap) is standard and fine for most homes. Triple glazing (three panes) is warmer and quieter but costs 30–40% more. In Wales, the extra cost often doesn't justify the benefit unless you're in a very noisy area or retrofitting a period home where insulation matters hugely. For most Cardiff homes, good double glazing with a low-emissivity (low-E) coating is the sweet spot — it's warm, cuts noise reasonably, and won't break the bank. If you're replacing windows specifically to reduce energy bills, upgrade the glazing spec (thicker glass, better gas fill between panes) rather than jumping to triple. A low-E coating reflects heat back into the room — ask about this; it costs little extra but makes a real difference.

Should I replace my windows all at once or one room at a time?

If you can afford it, do them all at once. Here's why: installation takes time, your home's open to the weather for days, and you'll pay for scaffolding or access equipment either way. Spreading replacements over months means paying setup costs multiple times and enduring disruption repeatedly. That said, budget is real. If you must phase it, do the worst-performing windows first (usually the north-facing ones or those with obvious gaps). Avoid splitting a room — if you replace three windows in a bedroom, the fourth will look shabby and perform worse. For a typical three-bedroom semi in Cardiff, a professional crew can replace 15–18 windows in 3–5 days. Plan for noise, dust, and temporary drafts. A good trader will seal gaps and minimize disruption; a rushed one won't.

What's the difference between uPVC, composite, and timber frames?

uPVC (plastic): Cheap, low-maintenance, thermal performance is fine with modern coatings. Downside: can yellow in sun, doesn't feel as solid, and isn't as durable as timber in extreme cases. Composite (wood core with outer plastic layer): Stronger than uPVC, looks better, warmer, but costs 20–30% more. Low-maintenance exterior, better feel. Timber: Beautiful, highest thermal performance, traditional look — ideal for listed properties or period homes. Requires regular painting/varnishing and is vulnerable to rot if neglected. In Cardiff, uPVC dominates because it's cheap and practical. Composite is growing popular because it balances look and durability. Timber is chosen for aesthetics and heritage reasons. For a standard semi or terrace, uPVC or composite will serve you well for 25+ years if installed properly. Choose based on what suits your home's character and your budget.

What building regulations apply to window and door replacement in Cardiff?

In Wales, replacement windows and doors must meet current Building Regulations for thermal performance (U-values), air tightness, and glazing safety. You need certification via a FENSA-registered installer or Building Control approval. If you hire a FENSA installer, they self-certify and notify Building Control automatically — no extra cost to you. If you hire someone not FENSA-registered, you'll need to contact Cardiff Council's Building Control and arrange an inspection (roughly £150–£300). For straightforward replacements with like-for-like frames, most traders are FENSA-registered and handle it seamlessly. For significant work (structural changes, new openings, cill repairs), Building Control involvement is heavier and more essential. Always ask upfront: 'Will you provide Building Regulations certification?' A dodgy trader will avoid this question; a professional will explain exactly how they'll handle it. Get it in writing in your contract.

Cardiff windows & doors 2026

Choosing a Windows and Doors Trader in Cardiff

Getting your windows and doors right matters. They're not a quick fix — they're a long-term investment that affects your home's warmth, security, noise levels, and how it looks from the street. In Cardiff, you've got plenty of choice, but not all traders are equal. Some focus on speed and cost-cutting; others take their time and do proper work.

This guide cuts through the noise. We'll walk you through what you actually need to know before you hire someone to replace or install your windows and doors — realistic costs, the accreditations that mean something, what Cardiff homeowners deal with specifically, and the hard questions to ask.

Whether you're dealing with draughty sash windows in a Victorian terrace, uPVC in a 1980s semi, or fitting new French doors in a modern extension, the principles are the same. You want someone who knows the job, can explain what they're doing, and won't disappear when it gets tricky. This guide will help you find them.

What Windows and Doors Cost in 2026

Prices vary wildly depending on what you're buying and who's installing it. Here's a realistic breakdown for Cardiff in 2026.

Replacement Windows (per window): Standard uPVC casement windows run £300–£600 fitted. If you want better thermal performance (energy-efficient double glazing), add £100–£200 per window. Timber sashes cost more — expect £800–£1,500 each for decent wooden sashes with proper draught seals. Aluminium frames sit in the middle: £600–£1,200 per window.

Doors: Standard uPVC or composite entrance doors installed: £400–£900. Quality composite doors (warmer, more durable) push toward £1,200–£1,800. French doors or bifold patio doors: £1,500–£3,500 fitted, depending on size and material.

Full Window Replacement (whole house): A typical three-bedroom Cardiff semi with 15–20 windows: £6,000–£12,000 for standard uPVC. Upgrade to energy-efficient frames and you're looking at £10,000–£18,000.

What Affects Price: Access difficulty (top floors cost more due to scaffolding), frame condition (rotten wood means extra prep work), glazing spec (self-cleaning or noise-reduction glass adds cost), and whether you need cill repairs or structural work.

Get three written quotes. Each should itemize materials, labour, and any structural repairs. Cheapest isn't always best — poor installation can ruin even good windows. A realistic quote should take time and account for your actual home's conditions.

Accreditations That Actually Matter

A few badges are worth checking; most aren't worth the paper.

TrustMark: This matters. It's a government-backed scheme for reliable traders. TrustMark members are vetted, insured, and bound by a code of conduct. If something goes wrong, there's a dispute resolution process. Any serious windows and doors trader in Cardiff should be TrustMark registered.

FENSA or Competent Person Scheme: Windows and doors involving glazing work must meet Building Regulations. A trader registered with FENSA or another recognized Competent Person scheme can self-certify their work. If they're not, you'll need to hire a Building Control inspector separately (cost and hassle). Always ask: 'Are you FENSA registered or equivalent?' Don't let them fob you off with vague answers.

Glass and Glazing Federation (GGF): Trade body with a code of conduct. Members must comply with standards and insurance requirements. It's a good sign if they're GGF-affiliated.

WHICH? Trusted Traders: Not universal, but if a trader has this endorsement, they've passed independent vetting.

What to Ignore: Generic 'qualified' claims, ISO certifications that don't relate to windows, or membership in bodies you've never heard of. Ask 'What bodies regulate your work in Wales?' A good trader will have a clear, honest answer.

Always check credentials directly with the issuing body online — don't take the trader's word for it.

Windows and Doors: What Cardiff Homeowners Face

Cardiff's housing stock tells a story, and it affects what you'll need.

Much of Cardiff was built between 1880 and 1960 — Victorian and Edwardian terraces, plus post-war semis and council estates. Older properties often have original timber sash windows (beautiful but draughty) or have been retrofitted with poor-quality early plastic frames that rattle and leak. Many need draught-proofing or full replacement. Newer estates and regenerated areas have standard uPVC, which works fine if installed properly.

Cardiff-Specific Issues: The Welsh climate — damp, windy, frequent rain — puts real stress on windows and doors. Poor seals fail quickly. Salt air near the bay can corrode metal frames. Terraced housing means less external wall insulation, so window performance matters more for your heating bills. Many older Cardiff properties have narrow reveals (the gap between frame and wall), which limits material choices for replacements.

Building Regulations enforcement in Cardiff is tighter than some areas. If you're doing significant work, expect inspections. A local trader familiar with Cardiff Council's Building Control team will navigate this smoothly.

Local Support: Wales has its own trade bodies and support schemes. The Federation of Master Builders Wales and local independent traders often have better knowledge of Cardiff's quirks than national chains. They understand Welsh damp, Welsh walls, and Welsh regulations.

When hiring, mention your street or neighbourhood if you can. A trader who's worked in Cathays or Canton recently has practical experience with similar properties to yours.

How to Hire a Windows and Doors Trader

Follow this process and you'll avoid most problems.

Step 1: Get Recommendations Ask neighbours, friends, or your local Facebook group. 'Who fitted your windows?' is a great question — personal recommendations are gold. Check online reviews on Google and Trustpilot, but read carefully; one angry person sometimes leaves multiple reviews.

Step 2: Check Credentials Before you get a quote, verify TrustMark status, FENSA registration, and insurance. A five-minute check now saves headaches later. Ask for proof of liability insurance (minimum £1 million for windows and doors work).

Step 3: Get Multiple Quotes At least three. Each quote should be in writing, itemized, and valid for 28 days minimum. If someone pressures you to decide immediately, walk away.

Step 4: Ask Hard Questions Don't just compare prices. Discuss your specific situation — is your wall damp? Are your frames rotten? Do you need scaffolding? A good trader will mention potential problems; a bad one will ignore them.

Step 5: Check References Ask for contact details of three recent Cardiff customers. Call them. 'Would you hire them again?' is the key question.

Step 6: Get a Contract Before work starts, sign a contract. It should cover: scope of work, materials, cost, payment schedule, start and completion dates, warranty details, and what happens if something goes wrong. No verbal agreements.

Step 7: Payment Terms Never pay the full cost upfront. Standard practice: 25% deposit, 50% on delivery/start, 25% on completion. If someone asks for full payment up front, don't hire them.

Eight Questions to Ask Before You Hire

Ask these questions. Their answers (and how they answer) will tell you a lot.

1. 'Are you TrustMark registered and FENSA registered?' Non-negotiable. If they hedge, move on.

2. 'Can you show me samples of frames and glazing in my home?' They should understand that uPVC looks different in different light, and colours vary. A good trader brings samples and discusses your actual choices.

3. 'What's your warranty, and who backs it — you or the manufacturer?' A typical window warranty is 10 years on frame and glass, 5 years on mechanical parts. Some traders offer extended warranties for an extra cost. Make sure they put it in writing.

4. 'How long will the installation take, and what disruption should I expect?' Realistic answer: one day per 5–6 windows, plus prep and cleanup. If they say one day for your whole house, they're rushing.

5. 'What happens if I find a problem after installation?' They should have a clear callback policy and a process for fixing defects. 'Contact the manufacturer' isn't good enough; they should handle it.

6. 'Do you handle Building Regulations certification, or do I need to arrange that separately?' If they're FENSA registered, they'll sort it. Confirm who pays for any inspection.

7. 'What will you do with my old frames and glass?' Ask if they recycle or dispose. Responsible traders mention this; dodgy ones don't care.

8. 'Can you give me references from three Cardiff customers I can call?' If they refuse or say 'clients are private,' be suspicious. A proud trader will offer them freely.

Cardiff windows & doors — the complete homeowner guide (2026)