Say exactly what is being supplied (frame, glass, opening style, sizes and finish for each window), what performance figures the manufacturer's paperwork gives, when fitting can start and why, and what is excluded, such as where making good stops, scaffold and hidden defects. AI can draft the wording from your spec sheet, but you supply every figure.
Most window quotes fail in three places: a spec that says "double glazed" and nothing more, a lead time counted from the day the quote was accepted instead of the day the order went in, and an exclusions list that leaves out making good, which is where arguments start. A specific quote is also easier for the customer to compare with two others and easier for you to defend afterwards. Below, one eight-window house is quoted line by line, then the wording and prompts are broken out so you can reuse them.
A schedule and price build-up for an eight-window house
The example job is a three-bedroom house with eight windows, supply and fit, surveyed in one visit, with invented prices. Each window gets a reference, a surveyed opening size in millimetres and the one thing that makes it different from the others. The supply prices come from the supplier's quote, and every other line carries its working so that nobody has to ask where it came from.
| Ref | Room | Opening (W x H, mm) | Style | Special glass | Supply price |
|---|---|---|---|---|---|
| W1 | Lounge | 1800 x 1350 | Casement, two opening sashes and a fixed centre | Clear | $1,180 |
| W2 | Dining room | 1200 x 1350 | Casement, one opening sash and one fixed | Clear | $820 |
| W3 | Kitchen | 1200 x 1050 | Casement, one opening sash and one fixed | Clear | $690 |
| W4 | Hall | 600 x 1200 | Fixed | Obscure | $310 |
| W5 | Bedroom 1 | 1500 x 1350 | Casement, two opening sashes | Clear | $980 |
| W6 | Bedroom 2 | 1200 x 1350 | Casement, one opening sash and one fixed | Clear | $820 |
| W7 | Bedroom 3 | 1200 x 1350 | Casement, one opening sash and one fixed | Clear | $820 |
| W8 | Bathroom | 600 x 900 | Top-hung | Obscure | $340 |
| Supply total | $5,960 |
| Line | Working | Amount |
|---|---|---|
| Supply of eight windows | Total of the schedule | $5,960 |
| Fitting | 2 fitters x 2 days x $520 a fitter-day | $2,080 |
| Internal making good | 8 openings x $90 | $720 |
| Removal and disposal of old windows | Skip and tip | $240 |
| Access tower for the first-floor windows | Two days' hire | $180 |
| Total | Sum of the lines above | $9,180 |
| Deposit on order (30 per cent) | $9,180 x 0.30 | $2,754 |
| Balance on completion | $9,180 minus $2,754 | $6,426 |
Add one line stating whether the prices include any tax. The deposit exists because the units are made to the surveyed sizes after the order is placed, so say that in a sentence and the question is answered before it is asked. Say too how long the prices stand: a supply price tied to a supplier's price list needs a validity date shorter than the list's.
The spec for each unit: frame, glass, opening, hardware, finish
A schedule gives the size and the price. The spec block says what the customer is buying. Every window needs the same fields in the same order, so a reader can run a finger down the page and compare two quotes.
- Reference, room and opening size, with the date surveyed and whether the size is the opening or the manufactured size.
- Frame material, profile name and colour inside and out.
- Glazing build-up: panes and thicknesses, cavity width, any low-emissivity coating, the gas fill and the spacer type, exactly as the supplier states them.
- Glass type for this window: clear, obscure, patterned, toughened or laminated, and why (privacy, or a location where safety glass is required by the rules for the room).
- Opening style and handing: which sash opens, and which way.
- Hardware: handles and locks, limiters, and the finish.
- Ventilation: trickle vents fitted or not, and where.
- Cill and board details: external cill depth and any internal board.
- Product reference or certificate number the figures in the performance section belong to.
Here is the block filled in for W5, the front bedroom. The specification values are examples; replace them with the supplier's.
W5, Bedroom 1 (front, first floor). Opening 1500 x 1350 mm, surveyed on [date]. Frame: [profile name], white inside and out. Glazing: sealed double-glazed unit, [pane thickness]-[cavity]-[pane thickness], low-emissivity coating, argon fill and warm-edge spacer, as stated on supplier quote [reference]. Glass: clear. Safety glass: [required or not required, decided at survey for this location]. Opening: both sashes open outwards, hinges give a clear opening of [width] by [height] mm, to be checked against any escape-opening requirement for this room. Hardware: multi-point locks and handles in white, limiters fitted with an emergency release. Trickle vents: fitted at the head of both sashes. External cill: [depth] mm. Product reference [code].
Two habits protect you here. Ask the supplier which words they use for the build-up and copy them, because a paraphrase can quietly describe a different product. And record at the survey who decides about safety glass, so the decision is not made for the first time by the factory.
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Buy nowPerformance wording: U-values, labels and what not to promise
Customers hear "energy efficient" as a promise about their bills. The quote can describe performance honestly using the figures the manufacturer's paperwork already gives. One independent rating body's window label prints four numbers: U-factor, where lower is better at keeping heat in; solar heat gain coefficient, on a scale of 0 to 1, where low numbers resist solar heat; visible transmittance, on a scale of 0 to 1, where higher lets in more natural light; and air leakage. It also lists condensation resistance on windows, where higher is better. Other schemes use other labels and call the first figure a U-value, so copy the names and units from your product's own paperwork.
Three points make the wording safer:
- Use the whole-window figure. The technical manual for the simulation software behind that rating scheme describes the total figure as an area-weighted average of the centre of the glass, the glass edge and the frame. It is therefore normally higher (worse) than the figure for the centre of the glass alone. If the paperwork gives only a glass figure, say that it is a glass figure.
- Ask how the figure applies to your sizes. The same manual notes that edge effects weigh more heavily on small windows, so a figure for one size may not hold for a much smaller unit such as W4 or W8.
- Check the unit next to every U figure. A figure in Btu units is about 5.7 times lower than the same window expressed in W/m²K, so 0.30 in Btu units is roughly 1.7 in W/m²K. Print 0.30 beside "W/m²K" and the window looks nearly six times better than it is.
| Draft wording | Problem | Better wording |
|---|---|---|
| "A-rated high-performance windows that will slash your energy bills." | No rating figure given and a savings promise nobody can keep | "Whole-window U-value of [x] W/m²K, as stated on the manufacturer's certificate for [product code]. A lower U-value means less heat passes through. Savings depend on your home, heating and use and are not guaranteed." |
| "Soundproof glazing." | No window is soundproof, and no figure is given | Quote a sound rating only if the manufacturer publishes one for the exact glass build-up, and name it as the manufacturer's figure |
| "Will end your condensation problems." | Condensation depends on room humidity as well as the window | "Trickle vents are included at the head of each opening window. Condensation depends on humidity in the room as well as on the windows." |
| "Burglar-proof locks." | An absolute claim | "Multi-point locking, as specified for each window." |
Lead times: count from the order and say who owns the date
Made-to-measure windows do not exist until the factory makes them, so the date that matters is the manufacturer's, not yours. A quote that promises "fitting within four weeks of acceptance" has hidden the survey, the size sign-off, the order and the factory's queue in a single optimistic phrase. Count from the order, quote the supplier's range, and say plainly that the fitting date follows the manufacturer's confirmation.
Here is the timeline for the eight-window house. The supplier's six to eight weeks is invented for the example, so use the range your supplier confirms in writing.
| Step | Day | Notes |
|---|---|---|
| Survey | 0 | Sizes, glass decisions and special items recorded |
| Quote accepted, deposit paid | 3 | |
| Customer signs the size and spec sheet | 5 | Nothing is ordered before this |
| Order placed | 6 | The clock for the supplier's lead time starts here |
| Supplier's order confirmation arrives | 7 | Reconcile it against the signed sheet the same day (see below) |
| Delivery, at 6 to 8 weeks from order | 48 to 62 | 6 + 42 = day 48; 6 + 56 = day 62 |
| Fitting, booked for the week after delivery | 55 to 69 | Two fitters for two days |
So the customer who accepted on day 3 is fitted between day 55 and day 69, which is 52 to 66 days after acceptance, roughly seven and a half to nine and a half weeks and not four. Say that, with the reasons, in the quote. The wording:
Your windows are made to the sizes you sign off on the size and specification sheet. We place the order once that is signed. The manufacturer currently quotes [x] to [y] weeks from order to delivery, and we book fitting for the week after delivery. We will send you the manufacturer's confirmed date as soon as we have it, and tell you within [x] working days if it changes. Special colours, very large units and specialist glass can lengthen the manufacturer's lead time; any such items on your order are listed on the schedule.
Choose your own promise for slippage and keep it. For a wider look at setting dates for made-to-order goods, the tutorial on made-to-order lead times covers the same logic for furniture, and the messages that follow the order can run from the routine in quote follow-ups that run themselves.
Exclusions and making good, written so they cannot be argued
"Making good" means different things to different people, and the customer's version usually includes decorating. Start from a draft most firms write, then rebuild it.
Price includes supply and fit of 8 windows. Making good where necessary.
"Where necessary" decides nothing, so the dispute begins on the day the old frames come out. Here is the rebuilt version for the same job, split into three lists:
| Included | Not included | Priced on discovery |
|---|---|---|
| Removal of the 8 existing windows and glass from site | Redecoration of reveals, walls or ceilings | Rot or damage found behind old frames or in cills and lintels |
| Supply and fit of the units on the schedule | Repair to render, brickwork or lintels beyond making the opening good for the new frame | Fixings that must be changed because the wall behind has failed |
| External sealing with [sealant type] and finishing trim | Curtain rails, blinds and window boards, which the customer removes first | Any extra access the survey did not foresee |
| Filling and plaster repair to the reveals, up to [x] mm per side at each opening | Disconnection or reconnection of alarm contacts | |
| Dust sheets and floor protection in the rooms worked in | Scaffold above the first floor | |
| Cleaning of the new glass and frames before we leave | Any permission the property needs | |
| Hazardous materials found during removal, which stop work on that opening until a specialist has dealt with them |
The third column does the quiet work. It tells the customer in advance that something behind the old frame may change the price, and how that will be handled. Here is the variation wording to put under it:
If we find damage behind an old frame, we will stop work on that opening, photograph it and send you a written price for the extra work before doing anything. You can accept, change or decline it, and work on the other openings carries on in the meantime.
For the pricing of those extras, how small builders price variations and change orders with AI works through the arithmetic. The workmanship promise on the finished job is a separate document from the manufacturer's product guarantee, and the workmanship warranty template shows how to word the exclusions in it.
Certification, guarantees and what the customer receives at handover
List the paperwork in the quote, so the customer knows on day one what they will be handed on the last day. For this job it might read:
- The manufacturer's product guarantee, with its term and how a claim is made.
- Our workmanship guarantee, with its term and exclusions.
- The performance data or certificate for the installed product reference, matching the figures in the quote.
- Any completion certificate or building-control sign-off that the rules for the property require for replacement windows. If one applies, name it and say when it is issued. Do not leave it to the small print.
- Care instructions: cleaning, hinge and lock maintenance, and how the trickle vents work.
"Guaranteed for life" belongs nowhere in the quote. Say who guarantees what, for how long, and what voids it. If your area uses an installer certification scheme, quote your membership number only if you hold it and it is current.
A prompt that drafts from the spec sheet and nothing else
Save the rules below once as the instructions of a ChatGPT or Claude project, then open a fresh chat inside it for each job. Paste the schedule, the certificate figures and the supplier's lead time yourself, and tell the assistant that anything missing stays missing.
You are drafting the specification, performance, lead-time and exclusions sections of a window installation quote for a homeowner.
Use ONLY the facts in the DATA block. Do not add any figure, rating, standard, certificate name, guarantee term, lead time or brand.
If something you need is missing, write [missing: field] and list the missing fields at the end.
Write plain British English. Describe what is supplied. Do not describe benefits.
Never use: A-rated, energy efficient, maintenance-free, burglar-proof, unbreakable, soundproof, no condensation, guaranteed savings, pays for itself, lifetime, premium, high-performance.
Sections, in this order:
1. Specification: one short paragraph per window reference with size, frame, glazing build-up, opening style, glass type and hardware.
2. Performance: the whole-window U-value and any other figure exactly as given, with its unit and the product reference, then this sentence: "Savings depend on your home, heating and use and are not guaranteed."
3. Lead time: the supplier's range counted from the order date, then a sentence that fitting is booked after the manufacturer confirms delivery.
4. Included and not included: two lists copied from the DATA block, adding nothing.
5. Documents at handover: list only what the DATA block names.
Finish with a list of every number you used and the DATA line it came from.
DATA
Schedule: [paste rows]
Product: [name and code]; whole-window U-value [x] [unit]; solar heat gain coefficient [y]; certificate reference [z]
Lead time: [x] to [y] weeks from order, per supplier confirmation dated [date]
Included: [paste]
Not included: [paste]
Documents: [paste]Ask loosely and you get brochure copy, like this:
Your 8 new A-rated windows are maintenance-free and burglar-proof and will pay for themselves within five years. Fitting within four weeks of acceptance. All making good is included.
Several claims here have no source in your data. "A-rated" is a rating that appears nowhere in it. "Maintenance-free" is untrue of any frame with hardware that needs cleaning and care. "Burglar-proof" is an absolute. "Pay for themselves within five years" is an invented payback. "Four weeks of acceptance" contradicts the supplier's six to eight weeks from order. And "all making good is included" contradicts the exclusions list. Feed those back as one correction and regenerate from the DATA block, then compare the number list at the end with your sheet. A figure that is not in your data is an invention.
Reconcile the supplier's order confirmation against the quote
The costliest window mistakes happen between the signed schedule and the factory order, where a row gets copied from a neighbour or a glass type is dropped. An assistant is good at this comparison because it does not tire of reading numbers. Paste both documents without names or addresses.
Compare the QUOTE SCHEDULE with the SUPPLIER ORDER CONFIRMATION below. For each window reference, check these fields: size, frame colour, glazing build-up, special glass, opening style, hardware and quantity.
Show a table with columns: ref | field | quote | confirmation | MATCH or DIFFERENT. If a field is absent from either document, write NOT STATED. Do not guess or correct anything.
After the table, list every DIFFERENT and NOT STATED row.
QUOTE SCHEDULE: [paste]
SUPPLIER ORDER CONFIRMATION: [paste]On the eight-window job, an illustrative reply lists two rows under DIFFERENT. W3, the kitchen window, is 1200 x 1050 in the quote and 1200 x 1350 in the confirmation, because the row above it was copied. W4, the hall window, is obscure in the quote and clear in the confirmation. Caught on day 7, both are a phone call to the supplier. Caught on day 50, the first is a window 300 mm too tall for the opening, made, delivered and paid for, and the second is a hall window the customer can see through. Run this check on the day the confirmation arrives and keep the table with the job.
Replies for the lead-time, condensation and rush-job questions
Draft the replies once, so that a rushed phone call does not produce a promise. Fill the brackets from your own paperwork.
"Why does it take so long?"
Each window is made to the sizes you sign off on, so the order can't go in until you've signed. The manufacturer currently quotes [x] to [y] weeks from order to delivery, and I'll send you their confirmed date as soon as we have it.
"Will new windows stop my condensation?"
Condensation depends on how much moisture is in the room as well as on the window. The quote includes [trickle vents at the head of each opening window]. I can't promise it will stop, and I'd rather explain what the ventilation does than guess.
"Can you fit them next week if I pay more?"
Not for made-to-measure windows, because the units don't exist until the factory makes them. I can ask the supplier whether any item can be brought forward and tell you what it would cost before you decide.
What to tick before the quote is sent
- Every window on the schedule has all the spec fields filled, or an explicit [to be confirmed] with a name against it.
- Every glazing build-up word matches the supplier's own wording.
- Every U figure is a whole-window figure, or is labelled as a glass figure, with the unit printed next to it.
- The product reference in the performance section matches the product reference in the spec.
- The lead time is the supplier's range, counted from the order date, with the fitting date described as following the manufacturer's confirmation.
- The included, not included and priced-on-discovery lists exist, and making good is described by a measurement and not by "where necessary".
- The documents list names what the customer will receive, including any completion certificate that applies to the property.
- Prices, the deposit and the validity date add up, and a named person has read the final text, because the assistant drafts and a person is accountable.
After the first five jobs on this template, note every place where a customer queried the quote or the fitting differed from it, and fold each lesson back into the wording. To turn the customer's first enquiry into a surveyed quote in the first place, see replying fast to window replacement leads, and for the survey itself, measuring and quoting on the doorstep with AI help covers capturing sizes without the transposed-digit mistakes above.
Questions installers ask about window quotes
Which U-value should the quote print?
Print the whole-window figure from the manufacturer's certificate or test data for the exact product, with its unit and product reference. A figure for the centre of the glass alone is normally better than the whole window, so using it flatters the product. If the paperwork only gives a glass figure, say that it is a glass figure.
Should lead time run from the quote or the order?
From the order. Made-to-measure units are manufactured after the customer signs off the sizes, so a lead time counted from acceptance hides the survey, sign-off and ordering steps. State the supplier's range from the order date and say the fitting date is confirmed once the manufacturer confirms dispatch.
Can AI work out the glass specification for me?
It should not. An assistant may blend two products' figures or invent a build-up that sounds plausible. Paste the specification and certificate data yourself, tell it to use only that data, and have a person compare every figure in the draft with the supplier's paperwork before the quote leaves.
What should I do when I find rot behind an old frame?
Stop work on that opening, photograph the damage, and send a written price for the extra work before doing it. Let the customer accept, change or decline, and carry on with the other openings meanwhile. A variation clause in the quote that says this up front makes the conversation far easier.
Further reads
- Glazier Software: Quoting and Scheduling Tools With AI Features — Compare quoting and scheduling software with AI features.
- Heat Pump Quote Template: Explain Options With AI, No Savings Promises — See the same no-promises approach for another installation.
- Kitchen Installation Quote Template: Scope and Exclusions With AI — Another installation quote built around scope and exclusions.
- Insulation Quote Template: Material, Thickness and Area Lines With AI — Quote lines where a rating figure has to be exact.
- Joinery Quotation Template: Bespoke Items, Finishes, Lead Times With AI — Made-to-order items and lead times in another quote.
- Loft Conversion Quote Template: Stages and Provisional Sums With AI — Handle unknowns with provisional sums instead of guesses.
- Blinds Quoting Software: Measure-and-Quote Tools and What AI Adds — Five blinds quoting tools compared on price lists, on-site measuring and cost, plus what their AI really does and a 20-cell audit to run before you trust it.
- AI Tool for Construction Planning: Pre-Start Checklist and Long-Lead Items — A 42-item pre-start checklist for small construction jobs, with prompts for scope, long-lead order-by dates and a risk register you actually review.
- Gutter Quote Template: Run Lengths and Downpipes Priced With AI — Turn a hand sketch into a fittings table, a priced quote and a site-visit checklist for gutter installation, with AI counting and you checking.
- AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.
Sources: the NFRC energy performance label page (the ratings printed on a window label), the LBNL and NFRC THERM and WINDOW simulation manual (how a whole-window figure combines glass centre, glass edge and frame). The schedule, prices, sizes and dates in the examples are illustrations.