Pricing window fitting jobs accurately is one of the most commercially important skills a self-employed joiner develops. Under-price and you erode margins on work that takes real time and skill; over-price and you lose jobs to competitors. Getting it consistently right requires a disciplined approach to material costs, labour time, overheads, and margin — and an understanding of where the common errors occur.
Material Costs
Your material cost starts with the window price from your supplier, but that is not the end of the list. A complete cost build-up for a window fitting job should include:
- Window and frame — the trade price from your supplier, including any options (obscure glazing, specific hardware, colour)
- Fixings — frame fixings, packers, and any specialist anchors for the substrate
- Sealants and foam — low-expansion window foam and external silicone; these are consumed per installation and must be costed in
- Cill and trim — internal cill boards, architrave, and any external finishing trim
- Waste disposal — the old frame must go somewhere; skip hire or a trade waste run has a real cost
- Delivery — if your supplier charges for delivery, factor this into the job, not your overheads
Using a trade account with a direct manufacturer gives you consistent pricing that you can plan around. See our guide on setting up a trade account with a window manufacturer for more on how trade pricing works.
Labour Time Estimates by Window Type
Labour is typically the most variable element in a pricing build-up. Realistic time estimates per window (for an experienced joiner working alone, including removal of existing and installation of replacement) are approximately:
- Standard casement (small to medium) — 1.5 to 2.5 hours (for reference, see Clyde Windows & Construction’s casement window service)
- Large casement or picture window — 2.5 to 4 hours (handling and weight add time)
- Sash window (replacing into existing box) — 2 to 3 hours
- Sash window (full frame replacement) — 3 to 5 hours
- Bay window (3-section) — 6 to 10 hours depending on complexity and bay roof condition
These figures assume straightforward access and no remedial work to the reveal. Add time explicitly for reveal repair, re-plastering, external re-pointing, and any scaffolding or access equipment requirements. For guidance on fitting techniques, see our article on how to fit a casement window.
Overheads and Margin
Your labour rate must cover more than your take-home pay. A self-employed joiner’s effective hourly rate needs to account for:
- National Insurance contributions
- Public liability and professional indemnity insurance
- Van running costs (fuel, insurance, maintenance, depreciation)
- Tool replacement and maintenance
- Non-productive time (quoting, admin, travel to survey)
- Holiday and sick time — you do not earn when you’re not working
HMRC’s guidance on self-employment is a useful starting point for understanding the full cost of trading on your own account. A common mistake is pricing at a day rate that would look reasonable as an employed wage but fails to cover the full cost of self-employment. As a rough guide, your charge-out rate should be at least 1.5× what you need to take home per hour to cover overheads and non-billable time.
Quoting vs Estimating
A quote is a fixed price for a defined scope of work. An estimate is an indicative figure that may change. Most residential clients expect a quote, not an estimate — which means you need to have surveyed the job properly before pricing it, following the same principles set out in BS 8213-4, the British Standard code of practice for window surveying. Never quote from a photograph or a description alone; always visit the site.
Include clear exclusions in your quote: what is not covered, what happens if additional remedial work is found on opening up, and how variations will be priced. A well-written quote protects both you and your client and reduces disputes.
Common Pricing Mistakes
- Forgetting to include waste disposal, sealants, and trim in the material build-up
- Underestimating time on sash and bay work
- Not costing for access — scaffolding on a two-storey extension is a significant addition
- Applying a fixed window count rate without surveying each opening individually
- Pricing material at retail rather than trade cost