A window supplier quotation comparison should start with scope, not the total at the bottom of the page. Different bidders may interpret the same enquiry differently. A comparison sheet exposes those differences and helps the buyer distinguish a real saving from an omitted requirement.

Issue one controlled specification

Send the same opening schedule and drawing revision to every bidder. Include quantities, dimension references, opening operation, glass, frame finish and project performance criteria. If an item is provisional, label it clearly instead of allowing one supplier to assume it is final.

Ask bidders to identify departures and alternatives in a separate list. A quotation that silently changes the glass or operation is difficult to evaluate. Keep the original proposal and any later clarification together in the comparison record.

Use one row for each opening type

Record the item identifier, quantity, offered configuration and unit price. Add columns for frame system, glass build-up, hardware, screens and required evidence. Mark information as confirmed, different or missing. This is more useful than treating every unanswered field as included.

Compare dimensions and quantities before calculating totals. Check whether combined assemblies, mullions and special shapes have been counted consistently. A small quantity error can distort the apparent ranking even when unit prices are reasonable.

Compare delivery and service boundaries

List packing, transport, unloading, installation, commissioning and making good. Record the stated delivery basis and location, currency and quotation validity. Do not treat a factory collection price as directly comparable to delivery at the project.

Ask who measures final openings, approves drawings and resolves site discrepancies. Clarify warranty documents, service-part references and the process for reporting damage. These responsibilities affect the purchase even when they are not expressed as a separate price.

Close questions before selecting a supplier

• Request written answers to missing specifications.
• Obtain revised prices for agreed changes.
• Keep alternatives separate from the base proposal.
• Identify unresolved risks or provisional allowances.
• Approve the final scope with the purchase documents.

A weighted decision can consider technical fit, documentation, communication and delivery capability alongside price. Use evidence for those judgments rather than a polished website or an unsupported claim. The selected quotation should be understandable to the installer and project team as well as the buyer.

Explore Shanghai Slang window options, including casement and sliding windows. Request a proposal against your controlled schedule so the comparison reflects the same product and responsibilities.