Window Fitting Costs UK — What to Charge for Window Installation and How to Price the Job (2026)

Window fitting is a volume-driven trade. Whether you work labour-only for a local fabricator or price supply-and-fit direct to homeowners, understanding what to charge for each window type — and how to justify that price — is what separates a profitable window fitter from one who stays busy but never gets ahead. This guide covers 2026 labour rates, the variables that move prices up and down, FENSA and Certass registration, how to handle repair work alongside replacement, and what to communicate to customers when quoting colour finishes and energy ratings.

Window Fitting Labour Rates (2026)

The rates below are labour-only — they assume the window unit is already on site and the fitter is replacing like-for-like in a standard masonry opening at ground or first floor level with no scaffold required. Add costs for access, making good, and frame disposal on top.

Day rate for an experienced window fitter: £220–£400/day depending on region and specialism. A two-person crew on supply-and-fit work typically fits 4–6 standard casement windows per day on a like-for-like domestic job.

What Affects Window Fitting Price

Labour rates for window fitting move significantly based on what the job actually involves. These are the most common factors that justify charging above the base rate:

• Scaffold or access equipment: Ground-floor windows with internal access require no special access. First-floor windows can usually be managed from a hop-up or podium inside; externally, you may need a scaffold tower or hired mobile scaffold. If a full scaffold is needed — typically on second-floor or above, or where there is no internal access — scaffold hire runs £400–£1,200 per week for a typical domestic house and must be priced as a separate line on the quote.
• Removing old frame vs leaving it: A pure like-for-like casement swap where you can slide the new frame into the old outer frame (cill-and-head system) is the quickest type of job. Full frame removal — taking out the existing outer frame and fixing the new unit directly to the masonry — takes 30–60 minutes longer per window and increases the risk of reveal damage. Price the difference: full frame removal typically adds £40–£80 per window to the labour cost.
• Lead flashing: Where a window sits beneath a flat or pitched roof section — common on lean-to extensions and bay window roofs — the lead flashing needs to be cut, lifted, and reinstated around the new frame. This adds £80–£200 per openingdepending on the extent of flashing work. Never reseal a window opening without checking the flashing condition; a failing flashings is one of the most common causes of post-installation water ingress complaints.
• Making good (plastering around the reveal): After fitting, the internal reveal may need filling, re-skimming, or in some cases partial re-plastering. A light fill and sand can take 15–20 minutes per window. A full reveal skim on rough blockwork can take an hour per window and requires plaster, beads, and float time. Be specific in your quote: state whether you are providing filling and priming only orfull skim and first fix decoration. The ambiguity between these two is the source of most window-fitting disputes.
• Ironmongery complexity: Standard friction stays, cockspur handles, and a single multipoint locking system are quick to fit. Tilt-and-turn mechanisms, shootbolt locking systems, restricted-opening child-safety stays, and heritage ironmongery all take longer to set up and align correctly. Budget an extra 20–40 minutes per windowfor complex ironmongery.
• Trickle vents: Under Approved Document F (ventilation), replacement windows in habitable rooms typically need trickle vents if the existing windows had them or if the overall ventilation strategy requires it. Cutting and fitting a trickle vent in an existing frame profile takes 10–15 minutes per window; specify whether this is included in the labour rate or priced separately at £15–£30 per window.

FENSA and Certass: What Window Fitters Need to Know

Window replacement in England and Wales is notifiable work under Building Regulations (Approved Document L — energy efficiency, Approved Document N — glazing safety). As a window fitter, you have two routes to demonstrate compliance:

Route 1: Competent Person Scheme (FENSA or Certass)

FENSA (Fenestration Self-Assessment Scheme) and Certass are the two Government-approved Competent Person Schemes for window and door replacement. Being registered means you can self-certify that your installation complies with Building Regulations without notifying the local authority building control on each job.

• Annual registration cost: £300–£600 per year, depending on the scheme and your turnover band. Both FENSA and Certass charge a tiered annual fee based on the number of installations you register per year.
• Per-job registration: A small fee — typically £15–£30 per property — is charged to register each installation and trigger the certificate. Most fitters pass this directly to the customer as a line item on the quote, or build it into their price.
• What you get: Each registered installation generates a certificate for the homeowner. This certificate is required documentation when the property is sold — solicitors and conveyancers routinely request it on property searches. A missing certificate typically results in the homeowner either buying indemnity insurance (£200–£400) or, in some cases, having windows replaced by a registered installer at their own cost.

Route 2: Local Authority Building Control

If you are not registered with FENSA or Certass, you must submit a building control application to the local authority before each installation. The authority will inspect on completion and issue a completion certificate. This costs £200–£500 per applicationdepending on the local authority and the scope of work, and adds delay and administrative burden to every job. For any business doing more than occasional window replacement work, FENSA or Certass registration is the only commercially viable route.

Supply-and-Fit vs Labour-Only: Structuring Your Business Model

Most window fitters operate one of two models — or a combination of both depending on the customer:

Labour-only (fitting only)

You arrive on site with the windows already delivered and fit them to a specification provided by the customer or the supplier. This model has lower capital requirements and no stock risk, but your income is limited to your labour rate. Day rates for labour-only window fitters in 2026 run at £220–£400/day depending on region and specialism. Many experienced fitters work this model exclusively for commercial contractors or fabricators who prefer to use their own trusted fitting teams rather than in-house labour.

Supply-and-fit (full package)

You source the windows from your fabricator, mark up the supply cost, and present the customer with a single installed price. This is the higher-margin model. A typical supply-and-fit margin on the window units themselves is 20–40% over fabricator cost, depending on the product range and your purchasing volume. On a £300 fabricator-cost casement window, that is £60–£120 per window in materials margin, before any labour charge.

The risk: you carry the quality risk on the unit. If a sealed unit fails, a frame is damaged in delivery, or a colour is wrong, the customer looks to you rather than the fabricator. Build a relationship with a fabricator who offers a minimum 10-year sealed unit guarantee and handles replacements efficiently — this is a genuine differentiator when explaining your price to customers comparing you against cheaper alternatives.

Energy Ratings and Colour Finishes: How to Communicate These in Quotes

Energy ratings

The British Fenestration Rating Council (BFRC) rates windows from A++ down to E. The Building Regulations minimum for replacement windows under Approved Document L is a whole-window U-value of 1.4 W/m²K or better — broadly equivalent to a C ratingas a floor. In practice, most reputable fabricators now supply A-rated as standard and offer A+ and A++ as upgrades.

• C-rated: Meets Building Regulations minimum. Acceptable but not a selling point.
• A-rated: Standard in most mid-range supply-and-fit quotes. Whole-window U-value typically around 1.2–1.4 W/m²K with argon fill and low-E coating.
• A+-rated: Premium double glazing with warm-edge spacer bars and higher-performance glass. Adds roughly £30–£60 per window on supply cost. Quote as a premium option.
• A++-rated: Typically requires triple glazing or a very high-specification thermally broken frame and gas fill. Adds £80–£200 per window on supply cost over A-rated. Worth offering on north-facing windows or properties targeting EPC Band B or above.

Name the energy rating on every quote. Customers who are comparing quotes from multiple fitters cannot compare value if one quote says “double glazing” and yours says “A-rated argon-filled double glazing with warm-edge spacer bar, whole-window U-value 1.2.” The second quote wins the quality perception argument without necessarily winning on price.

uPVC colour finishes

White uPVC is the standard reference price. Any coloured finish increases the frame cost:

• Anthracite grey (RAL 7016), black, cream: The most popular non-white finishes. Add 15–25% to the frame supply cost over white. A £280 white fabricator-cost casement becomes £322–£350 in anthracite.
• Dual-colour (white inside, colour outside): Very popular on front elevations where the homeowner wants the kerb-appeal of grey externally but a white internal finish that matches their decor. Adds roughly the same premium as single colour — 15–25% — because the foiling process is similar.
• Woodgrain effect: Rosewood and golden oak were the dominant alternatives to white for two decades; they are now declining in popularity but still specified on some traditional-style builds. Similar price premium to solid colour — 15–20%.

State the colour finish explicitly in every quote. “uPVC windows” is not enough — a customer who later discovers that anthracite costs extra will feel misled, even if you did not intend to mislead them. Quote white as the base and show the colour upgrade as a clear line item so the customer is making an informed choice.

Window Repair Pricing: Handle, Hinge, Sealed Unit and Draught-Proofing

Repair work is a consistent source of revenue between larger installation contracts. It also functions as a customer acquisition channel: a homeowner whose window handle you fix today is a natural prospect for a full replacement quote in two or three years. Price repairs fairly — not cheaply — and do the job properly.

Condensation between panes: identifying failed sealed units

Condensation or misting between the panes of a double-glazed unit is the most common window fault reported by homeowners. It always indicates a failed sealed unit — the hermetic seal between the two panes has broken, allowing moist air in. Once the seal goes, it cannot be repaired: the unit must be replaced.

When assessing a misted unit, check whether the frame itself is still sound. If the frame is in good condition and the unit failure is isolated, a sealed unit replacement is the right recommendation at £80–£200 per unit (including glass and labour). If multiple units in the same frame are failing, or the frame itself is deformed, drafty, or more than 15–20 years old, a full window replacement is the more cost-effective long-term option — and you should explain this clearly rather than repeatedly patching an ageing frame.

On the survey, check for: condensation between panes, staining or mould at the corners of the frame (indicating water ingress past the seal), failed mastic around the perimeter, and whether the frame opens and closes squarely. These four checks take two minutes per window and allow you to quote for the actual scope of work rather than finding problems mid-job.

How to Write a Window Fitting Quote That Wins Work

Most homeowners getting multiple quotes for window replacement cannot compare them properly because each quote is written differently. A quote that is specific and transparent wins on perceived quality even when the price is not the lowest. Here is what to include:

• Window type and specification per opening: Frame material, profile system (e.g., “Deceuninck 2800 series 76 mm uPVC”), colour finish, glazing specification (e.g., “4/16/4 argon-filled low-E, A-rated”), and energy rating.
• Labour scope: State explicitly whether full frame removal is included or whether you are fitting into the existing outer frame. State what making-good is included — fill and prime, skim and prime, or full first-fix decoration.
• Access and scaffold: If scaffold is required, either include it as a quoted line item or state clearly that it is excluded and give a separate indicative cost. Never leave scaffold as an undefined risk.
• FENSA / Certass certificate: State your scheme membership and confirm a certificate will be issued to the homeowner for each installation. If you are passing the per-job fee to the customer, show it as a line item (£15–£30 per property).
• Waste removal: Confirm old frames and glass are included in the price. Glass disposal has specific requirements — it cannot go in a standard skip — and handling it professionally is a point of difference.
• Payment terms: A 30–40% deposit on order and the remainder on installation completion is standard for window replacement work. State this on every quote.
• Lead time: Confirm the expected installation week at quote stage, not just after the deposit is paid. uPVC windows typically take 2–4 weeks from order. Timber windows can take 6–12 weeks. Customers who are not warned about timber lead times often cancel the order and go to a uPVC competitor.

Tracking Which Marketing Channels Drive Full Replacement Contracts

For a window fitting business, not all enquiries are equal. A call from Google Ads asking about a single misted unit is a very different job from a homeowner enquiring about a full-house replacement after seeing your van parked outside a neighbour's property. Both are worth taking, but they have very different values — and if you are spending marketing budget on Google Ads, Checkatrade, leaflet drops, and van signage without knowing which channels generate the high-value full-house contracts, you are flying blind.

The breakdown to track is: enquiry source (how they found you) against job value (total invoiced amount) and job type (full replacement, single window, repair). After three to six months of tracking this data, most window fitters find that one or two channels — often referrals and van signage — generate disproportionately high-value jobs, while lead generation platforms bring in more repair call-outs. That is not necessarily a problem, but it changes how you allocate your marketing spend.

Trade2Base tracks enquiry source against job value so you can see which channels are generating full window replacement contracts versus single-unit repair call-outs — and make informed decisions about where to invest your marketing budget next quarter.