The big firms sell on paperwork, not workmanship
A glossy quote with a discount that expires on Friday still beats a handwritten total for most homeowners, whatever the price difference. You need a document that looks like a business wrote it.
For window fitters
Window estimates that stand up next to a national firm
You are being compared against a company with a brochure, a finance option and a salesman who sat in the front room for two hours. What you have is a better price and better work. A clear, itemised estimate is what makes that visible.
Why estimating is the worst part of the week
Bays hide their problems until the old frame is out
Support poles, a rotten cill, render that lets go the moment you touch it. If none of that is on the estimate, all of it is on you.
Making good inside is always somebody else
The customer expects the plaster round the reveals to look new. Unless the estimate says otherwise, they expect it from you and for free.
A real example
Eight uPVC windows and a composite front door
On the left is what you would actually write down. On the right is what your customer receives.
Your notes
8 windows and the front door. all upvc, anthracite grey outside white in, foiled. survey done. two of them sit under a lintel, fine. the front bay IS load bearing, prop it with acrows and strongboys, and it needs support poles in the mullions plus a new cill, the old ones rotten through. trickle vents on everything now, part F. 3 first floor openers need egress hinges for escape. composite door anthracite, chrome furniture, 3 star cylinder, its a corner plot so tell them about the security rating. FENSA it. 2 days 2 fitters. old frames and glass separated at the tip. silicone and trims externally, if the plaster blows internally thats a plasterer, make that clear in writing this time
The estimate
| Item | Qty | Amount |
|---|---|---|
| Site survey and templating of all openings | 1 job | £140.00 |
| uPVC casement window, foiled anthracite, supplied and fitted | 7 each | £4,340.00 |
| Bay window, supplied and fitted with support poles and new cill | 1 each | £1,650.00 |
| Composite front door with 3-star anti-snap cylinder | 1 each | £1,450.00 |
| Egress hinges to first-floor escape windows | 3 each | £144.00 |
| Trickle vents to all openings, Part F compliant | 8 each | £176.00 |
| Temporary propping to bay, acrows and strongboys | 1 job | £260.00 |
| External silicone, trims and making good | 1 job | £320.00 |
| FENSA registration and Building Regs certificate | 1 job | £85.00 |
| Remove and recycle old frames and glass | 1 job | £240.00 |
| Total before VAT | £8,805.00 | |
An illustration using typical UK rates, not a price list. TradeScribe prices from the rates in your own notes and your saved day rate.
What we know about window installation estimates
These are the lines that come up again and again on a window fitter's estimate. Mention any of them in your notes, however briefly, and they come out properly worded.
- uPVC casement window, supplied and fitted
- Bay window replacement with support poles
- Composite or uPVC front door, fitted
- Patio or French doors, per set
- Aluminium bi-fold doors, per metre of opening
- Trickle vents to satisfy Part F
- Egress hinges to escape windows
- Temporary propping to structural openings
- FENSA registration and certificate
- Removal and recycling of old frames
Window installation estimating questions
Do I need to be FENSA or Certass registered to quote replacement windows?
To self-certify, yes. Replacement windows and doors in England and Wales are notifiable under Building Regulations, and without a competent person scheme you must notify Building Control and pay their fee instead. Whichever route you use, show it as a line on the estimate: it is the certificate the homeowner will need when they come to sell.
How do I price a bay window replacement without seeing behind the render?
Assume the worst and say what you assumed. Price the propping and a new cill in, then add a stated rate for structural repair found on removal. Bays carry load, and the difference between a straightforward swap and a rebuild is discovered about ninety seconds after the old frame comes out.
Should my estimate mention U-values and Building Regs compliance?
Yes, and it is one of the easiest ways to look more professional than a competitor who does not. State the glass specification and the window energy rating you are supplying. It also protects you: if a customer asks you to fit something cheaper that would not comply, you have the original specification in writing.
What do I say about making good the plaster inside?
Exclude it plainly. Say that internal reveals are left with the existing plaster made good to a fair finish, and that replastering and decorating are not included. Old render and lime plaster often let go when a frame comes out, and a customer who was never told expects a decorated finish for nothing.
How long should a window estimate stay open?
Thirty days is sensible and it should be printed on the estimate. Frame prices move with the exchange rate and the glass surcharge, and a customer holding a quote from six months ago will absolutely expect you to honour it. A stated expiry date is not aggressive, it is normal in every other industry.
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