A cheaper window quotation is only cheaper when it includes the same windows, evidence, accessories and delivery responsibilities.
Three totals sit in the tender sheet. The lowest is highlighted green. Two pages later, that supplier has excluded screens, subframes and special packing; another has changed the glass; the third priced an older schedule. Before ranking prices, rebuild the comparison around scope.
Lock one comparison baseline
Issue the same drawing revision, schedule and clarification log to every bidder. Record the return date and do not silently combine answers from different revisions.
If a late addendum arrives, ask every supplier to show the delta rather than replacing the earlier quote without explanation.
Normalize the technical offer
Create one line for each window mark and compare system, dimensions, opening, glass, finish, hardware and quantity. Flag substitutions rather than hiding them inside a note.
A substitution may be sensible, but it needs a technical and commercial decision—not automatic acceptance because it lowered the total.
- Profile and thermal break
- Glass and spacer
- Finish and colour
- Hardware and screens
- Performance evidence
- Unit quantity
Put every exclusion in the price table
Separate subframes, trims, flashings, sealants, fixings, accessories, spares, samples, testing, packing, freight, unloading and installation support.
Use three states: included, excluded, or allowance. A blank cell is not an answer.
Compare risk that has not been priced
Note unverified sizes, missing structural review, unapproved colours, evidence gaps and provisional shipping assumptions. These are not always reasons to reject a bid, but they are reasons not to treat the total as fixed.
Assign each open item an owner and closure date. The comparison becomes much more useful when uncertainty is visible.
Write the award basis in one page
Summarise the selected scope, accepted deviations, remaining conditions and documents that form the order. Attach the final comparison and clarification log.
Months later, this page should explain why the chosen offer was commercially complete—even if it was not the lowest first number.
Questions buyers ask
Can quotations in different currencies be compared directly?
Only after using a dated exchange-rate basis and aligning freight, tax, duty, payment terms and validity.
How should optional items be handled?
Keep options outside the base comparison and show their technical impact and price separately.
What is the most common hidden omission?
It varies, but screens, subframes, trims, packing, testing and site-related scope frequently create later differences.
Continue the project review
Connect this guide with the proposed window and door systems, then review how Cavorlen approaches manufacturing and quality control. When your schedule is ready, send it through the project review form.
Primary references
Incoterms® rules — ICC ↗FGIA — technical resources ↗Related buyer guides
Exact systems, performance, price, programme, delivery and warranty require authorised project-specific review.