Is it the same specification?
Frame series, glass composition and hardware can differ even when the brand and dimensions match.
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Aluminum window quote checklist
Same window project.What makes the quotes different?
Look beyond the total. Compare each window’s specifications, then the removal, installation and finishing costs. Are both quotes covering the same work?
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One entry for each window
Window specification sheet
- Location & quantity
- Room / reference, dimensions, count
- Frame & glass
- Series, model, glass composition
- Hardware & screens
- Specifications, quantities, options
- Installation & finish
- Scope, responsibility, cost
Make the deliverables explicit
- Read
- Compare
- Discuss
SII / START HERE
“Airtight windows, installed” leaves three questions open.
Place the details for the same window side by side. If any of these differ, note the difference before comparing prices.
Does the price cover the same work?
One quote may include removal and wall repairs; another may cover only the new window installation.
Are the completion terms the same?
Compare the checks, warranty scope and payment conditions too.
Twelve details to check in your quote.
Open any item that is unclear. You’ll find what to look for and a question to ask. This checklist does not score the quote or certify the work.
01—04 / SPECIFICATION
What you’re buying
Can you identify every window?
List the room or window reference, type, width, height, quantity and opening direction. Include measurement units, unit prices and subtotals instead of one combined quantity.
Ask the contractor
Please list each window’s location, type, dimensions and units, quantity, opening direction, unit price and subtotal.
Which series—not just which brand?
A brand name does not identify the full specification. Add the frame series, model and finish. If the quote mentions air, water or acoustic performance, ask for information that matches the specified product.
Ask the contractor
Please identify the frame brand, series, model and finish, with product information supporting any performance claims in the quote.
What is the glass made up of?
Check the glass type, layers, thicknesses, colour and processing. A single thickness does not make single-pane, laminated and insulated glazing equivalent. Ask an appropriate professional to confirm suitability for the location.
Ask the contractor
Please list the glass type, layer thicknesses, composition, colour and processing, and any conditions that still need an on-site assessment.
Which hardware and screens are included?
Check the handles, locking points, rollers, hinges, restrictors and insect screens relevant to each window. Identify models and quantities, separating included parts from optional extras.
Ask the contractor
Please list hardware and insect-screen specifications and quantities, distinguishing included parts, options and extra charges.
05—08 / SCOPE
What installation includes
Does the total include removal and disposal?
Check old-window removal, waste disposal, carrying or lifting, and protection of rooms and shared areas separately. “Installation included” does not say whether these costs are covered.
Ask the contractor
Which removal, waste-disposal, carrying or lifting, and protection costs are included in the total?
Who repairs the surrounding wall?
Opening repairs, plastering, painting and tile repairs may be handled by different people. Define the extent, finish and responsible party so the work does not fall between two quotations.
Ask the contractor
Who handles opening repairs, plastering, painting and tile repairs? Which areas and finishes does this quotation include?
Where does each installer’s work end?
Ask who fixes the frame, fills the joints, waterproofs the outside and finishes the inside. Record the proposed materials, methods and boundaries; this is a scope check, not a DIY waterproofing specification.
Ask the contractor
Please identify the materials, proposed methods and responsible party for frame fixing, joint sealing, external waterproofing and internal finishing.
What if the final measurements differ?
Record the dimensions and site assumptions used for the quote. Agree how changes found during remeasurement or removal affect price and timing, including additions and reductions.
Ask the contractor
How will differences found during remeasurement or removal affect cost and timing? Who confirms the written change and price before work proceeds?
09—12 / TERMS
What happens at completion
When will the work happen?
Check dates for measuring, fabrication, access, installation and expected completion. Include building rules and working hours, plus notification and rescheduling arrangements for weather or site changes.
Ask the contractor
Please set out the measuring, fabrication, installation and expected completion schedule. How will access restrictions, weather or site changes be communicated and rescheduled?
What will be checked at completion?
List operation, locking, drainage, appearance and leak-related checks. Appropriate professionals should confirm methods and test conditions. Record outstanding items and how they will be corrected.
Ask the contractor
How will operation, locking, drainage, appearance and leak-related items be checked? Who agrees the conditions, records the results and arranges corrections?
Does the warranty cover the joints too?
Frame, glass, hardware and sealing or waterproofing coverage can differ. Record each scope, duration, start date, exclusion and contact—not only “full window warranty”.
Ask the contractor
Please state the separate warranty scope, duration, start date, exclusions and contact for frames, glass, hardware, and sealing or waterproofing.
What is each payment linked to?
Read the deposit purpose and later payment conditions separately. Match them to measurement approval, delivery, installation or acceptance, with the records needed before payment is requested.
Ask the contractor
Please explain what the deposit covers and which measurement, delivery, installation or acceptance conditions and records support each payment.
A fitted window is not the same as a finished opening.
Write down who handles each part of the surrounding work. If another contractor takes over, record the boundary and sequence in the quotation attachments.
Existing opening
Who removes the old window and repairs the opening? How are newly discovered problems agreed?
Frame & joints
Who fixes the frame, seals the joints and waterproofs the outside? With which materials and methods?
Inside & outside finishes
Who completes the trim, paint or tile repairs? What finish will be left at handover?
Leaks, structural concerns and safety questions need an on-site assessment by appropriate professionals. This guide checks the written quotation; it does not specify glass thickness, waterproofing methods or performance levels.
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Ask for a quote you can check, line by line.
Copy the questions below, add your room or window references and quotation version, and remove anything that does not apply before sending.
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Already have two quotes?
Align the specifications and included work, then compare them item by item.
A few common questions
Is a brand name enough detail?
No. Ask for the series, model, glass and hardware configuration, and finish. If acoustic, air or water performance is mentioned, request information that matches the specified product. A brand name alone does not provide those details.
Is thicker glass always the better choice?
Thickness alone does not determine suitability. Glass type and composition, window type, dimensions and site conditions need to be considered together. Ask for the specification in writing, then have an appropriate professional confirm the selection.
Does “installation included” cover removal and disposal?
Do not assume it does. Check removal, carrying or lifting, disposal, protection, opening repairs and finishing separately. Included work and extra charges should be clear in the quotation or its attachments.
Does “silicone sealing” fully describe the waterproofing?
That phrase does not identify the material, locations, preparation, method or scope of responsibility. Ask the contractor to add those details. Whether the method is sufficient needs professional assessment of the site, not a conclusion from that phrase alone.
Can SII recommend a window contractor or judge the market price?
SII reviews the documents provided. It does not rate contractors or replace an on-site assessment, engineering judgment or market valuation. Clearer quotation details help you compare and ask questions; they do not guarantee product performance, workmanship or results.
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Have a quote, but still unsure what’s missing?
Upload the complete quotation for Free Key Results. SII reviews the information and conditions in the document to help you decide what to ask next.