Window Replacement Costs UK — uPVC, Aluminium and Timber Prices Per Window (2026)

Window replacement is one of the most common home improvement jobs in the UK — and one of the most price-sensitive. Homeowners are bombarded with online calculators, leaflet drops and free-survey offers, so when they call you they often already have a number in their head. Knowing the real market rates for uPVC, aluminium and timber windows in 2026 keeps your quotes competitive and your margins intact.

Why Windows Get Replaced

Most replacement enquiries fall into one of five categories. Understanding which one you're dealing with shapes how you write the quote and which product you recommend.

• Draughts and air infiltration. Failed seals, warped frames or worn weatherstripping let cold air in and warm air out. The customer feels it instantly and it shows up on their energy bills.
• Condensation between panes. When the argon-filled cavity in a sealed unit fails, moisture tracks in and the glass fogs permanently. The unit can't be cleaned — it must be replaced. This is the single most common trigger for a call to a window fitter.
• Rotting or failing frames. Timber frames are vulnerable to moisture ingress at the cill and joints. uPVC frames can crack, discolour or warp over time, especially on south-facing elevations with heavy sun exposure.
• Noise reduction. Properties near roads, railways or flight paths see big uplift from acoustic glass or thicker laminated inner panes. Customers here will often pay more for the right specification.
• Energy efficiency upgrades. Since Building Regulations Part L tightened in 2022 and energy prices spiked, many homeowners are proactively replacing single-glazed or older double-glazed units to cut heating costs. A-rated windows are now the entry expectation, not a selling point.

uPVC Window Costs (Supply and Fit)

uPVC remains the dominant material for replacement windows in the UK — low maintenance, good thermal performance and the widest range of styles at the most accessible price point. All prices below are supply-and-fit including VAT and disposal of the old frames.

The wide ranges reflect glass specification, colour finish (white is cheapest, woodgrain foil adds 10–15%), hardware grade and site-specific factors like access, reveal depth and lintel condition. A like-for-like white casement replacement is at the lower end; a coloured profile with triple glazing sits at the top.

Aluminium Window Costs

Aluminium frames are thinner, stronger and carry a premium aesthetic. They suit contemporary extensions, architect-designed houses and commercial premises. Expect prices 20–40% above equivalent uPVC specifications.

Powder-coat colour options (RAL palette) add cost at the factory stage and extend lead times to 6–10 weeks from most fabricators. For bifolds and large aluminium screens, structural opening preparation — lintels, DPC, cill dressings — is often additional and should be itemised separately in your quote.

Timber Window Costs

Timber is required by planning condition in conservation areas and listed buildings, and remains the preferred choice for period properties where authenticity matters. It commands the highest labour cost due to the skill involved in fitting and finishing.

Listed buildings require like-for-like replacement using timber — usually softwood painted white to match the original. Any deviation (e.g. introducing double glazing into a single-glazed listed window) requires listed building consent from the local authority. Warn customers upfront: consent can add 8–12 weeks to the project timeline and retrospective consent is not guaranteed. Always factor in the paint finish — factory-primed timber still needs a site-applied topcoat, which is chargeable.

Double vs Triple Glazing

The shift from double to triple glazing has accelerated in the UK since energy costs rose sharply. Here's how to frame it for customers and how it affects your pricing.

Triple glazing adds 20–30% to the unit cost but reduces heat loss through the glass by roughly 40%. The payback period is typically 8–15 years depending on heating costs, so it makes most commercial sense on north-facing elevations or rooms with large glazed areas. Triple glazing also adds weight — frames and fixings must be rated to take it, and some older reveals won't accommodate the increased frame depth.

Energy Ratings and Building Regulations

All replacement windows in England and Wales must meet Building Regulations Part L (conservation of fuel and power). Since the 2022 revision, the minimum centre-pane U-value is 1.2 W/m²K, though most modern double-glazed units comfortably beat this.

Window Energy Ratings (WER) are issued by the British Fenestration Rating Council (BFRC) and run from A++ (best) to E (worst). A-rated is the practical minimum for most replacement projects — B or C-rated products are increasingly hard to justify when A-rated units are available at similar cost. Customers asking about energy bills will respond well to seeing the WER label; include it in your quote documentation.

FENSA and CERTASS Registration

Replacement windows and doors in England and Wales are notifiable work under the Building Regulations. Rather than submitting a full plans application to the local authority, window companies use a Competent Person scheme — either FENSA or CERTASS — to self-certify their installations.

Why this matters to your customers: a FENSA or CERTASS certificate is required when a property is sold. The solicitor's conveyancing pack will flag any replacement windows or doors installed after April 2002 and ask for the certificate. Without it, the vendor must apply to the local authority retrospectively — a process that costs £100–£200, takes 4–8 weeks, and creates uncertainty that can hold up a sale.

If a homeowner approaches you to fit windows and the previous installer wasn't FENSA-registered, you cannot retrospectively certify their work — only the original installer can. Make sure your marketing and quote documents prominently state your scheme membership; it is a genuine differentiator when customers are comparing quotes.

Draught-Proofing as an Alternative

Not every window needs full replacement. For period properties where the original frames must be retained (conservation areas, listed buildings, or customers who simply want to preserve character), draught-proofing is a cost-effective and often appropriate first step.

Brush seals, compression seals and window film can be fitted for £10–£30 per window in materials, plus labour. A skilled joiner can draught-proof a sash window in 1–2 hours. For properties where draught-proofing is the right recommendation, saying so builds trust and referrals — even if it's a smaller job than full replacement.

Installation: What to Expect on Site

A typical window replacement crew is one fitter and one labourer. Output depends on window size, access and the condition of the existing reveals, but a realistic working rate is 2–4 standard casement windows per day. Bay windows, sash windows or any opening requiring structural work will take considerably longer.

• Half-day minimum call-out. Even a single sealed unit replacement should be priced with at minimum a half-day on site — travel, set-up, disposal and snagging all take time.
• Lead times. Standard uPVC frames are typically 2–4 weeks from order. Aluminium in RAL colours is 6–10 weeks. Hardwood timber is 4–8 weeks. Always confirm lead times with your fabricator before committing dates to the customer.
• Structural checks. Before removing the old frame, confirm the lintel spans correctly and is in good condition. Cracked or undersized lintels need to be addressed before new frames go in — if you miss this, it becomes your problem.
• Disposal. Old frames and glass are non-hazardous trade waste. Include a skip or bag-and-van charge in your quote. Customers often assume disposal is included; make it explicit either way.

Quoting: Supply-Only vs Supply-and-Fit

Some customers — particularly developers and experienced self-builders — will ask for supply-only pricing. There are legitimate reasons to take this work, but price it carefully:

• Supply-only removes your installation margin but keeps the fabrication margin. Make sure you're not effectively doing free survey and design work for a customer who will then use a cheaper installer.
• Charge for the survey visit on supply-only jobs. £75–£150 per visit is standard and deductible on order. This filters out tyre-kickers and covers your time if the order doesn't proceed.
• For supply-and-fit, the survey is usually free — but protect yourself by specifying in writing that the quote is based on survey findings, and any hidden structural issues found during removal are chargeable as variations.

Guarantees: What to Offer and Why It Matters

The window industry has standard guarantee expectations that customers are increasingly aware of. Your quote should explicitly state your guarantee terms — it's a selling point and protects you from ambiguity later.

Frame and glass guarantees are backed by the fabricator; installation guarantees are yours. Make sure any guarantee you offer is backed by your FENSA or CERTASS membership — both schemes provide deposit protection and guarantee insurance, which is a genuine advantage to promote.

Red Flags: What to Avoid (and Warn Customers About)

The replacement window market has attracted its share of poor practice. Being transparent about what legitimate window fitting looks like builds trust and positions you against less scrupulous competitors.

• No FENSA or CERTASS registration. Any company fitting replacement windows in England and Wales without scheme membership is either unaware of the regulations or is cutting corners. Either is a problem.
• No written specification. A quote with a lump sum and no product details — profile system, glass specification, energy rating, hardware grade — gives the installer licence to downgrade at every stage. Always provide a written spec.
• Per-window prices on the phone without a survey. Legitimate window companies survey before quoting. A company that gives a firm price over the phone without seeing the property is either quoting to win and will add costs later, or is fabricating cheap product you wouldn't want your name on.

How Trade2Base Helps Window Companies Win Better Jobs

Window replacement is a high-ticket, high-competition market. You might be running Google Ads, paying for Checkatrade, handing out leaflets and relying on word of mouth — all at the same time. The problem is that without tracking, you have no idea which of these is actually filling your order book with profitable jobs.

Trade2Base gives window companies a simple dashboard that connects every lead back to its source — whether that's a Google Ad click, a directory listing, a referred customer or a repeat job from your existing database. You can see which channels are generating enquiries that convert into fitted jobs, and which are burning budget on tyre-kickers.

When you know a bay window installation converts 3x better from Google Ads than from a directory listing, you can shift your budget accordingly. That's how window companies with the same turnover as their competitors consistently run higher margins — they know where their best work comes from, and they double down on it.