Choosing a window and door supplier is a decision that affects product quality, project coordination, delivery and long-term maintenance. A professional website, a recognizable brand name or an attractive quotation can help buyers identify potential suppliers, but these factors alone do not establish whether a company can deliver the exact products required for a project.

Before placing an order, homeowners, distributors, architects and contractors should verify the supplier’s identity, proposed product configuration, technical documentation and contractual responsibilities.

This guide is published by Feiyu to help international buyers prepare enquiries, compare proposals and identify information that should be confirmed before production begins.

1. Define Your Project Before Evaluating Suppliers

A supplier cannot prepare a meaningful technical proposal without understanding the project.

Start by providing the building location, project type, opening schedule and approximate dimensions. Explain whether the order is for a private residence, villa, apartment development, hotel or commercial building.

The project information should include:

• Building location and local climate

• New construction or replacement installation

• Window and door quantities

• Opening dimensions and preferred opening methods

• Glass and appearance requirements

• Required thermal, acoustic, air, water and wind performance

• Destination-market requirements

• Expected delivery date

• Installation arrangements

Separate essential requirements from preferences. For example, a required performance threshold should be clearly distinguished from a preferred frame color.

Where requirements are not yet defined, ask the project architect or engineer to establish them before approving the final specification.

2. Verify the Legal Company Behind the Brand

A brand name may differ from the company that manufactures the products, signs the contract or provides the warranty.

Ask the supplier to identify the legal contracting company and explain its relationship with the brand. Confirm whether the company is a manufacturer, trading company, distributor or another type of supplier.

Request the relevant business registration information, manufacturing address and business contact details. Check that the company named on the contract and invoice is consistent with the agreed transaction.

If payment is requested to a different company, obtain a written explanation and verify the arrangement before proceeding.

Important questions include:

• Which legal company will sign the contract?

• Which company will manufacture the products?

• Which company will receive payment?

• Which company will manage quality issues?

• Which company will provide the warranty?

The aim is to establish a clear chain of responsibility before the order is placed.

3. Confirm the Actual Manufacturing Scope

A supplier may produce complete windows and doors, fabricate products using another company’s system, supply profiles and components, or coordinate production through partner factories.

These arrangements can all be relevant to procurement, but buyers need to understand what is included.

Ask which operations are carried out by the supplier and which are outsourced. Depending on the order, these may include profile processing, surface treatment, glass procurement, assembly, quality inspection and packaging.

For substantial orders, consider a factory visit, a live video walkthrough or an independent inspection. Review whether the production activities shown are relevant to the products being quoted.

Factory photographs provide background information, but they do not establish the configuration, workmanship or performance of a particular order.

4. Request a Product Schedule for Every Opening

A quotation described only as “thermal break aluminum windows” leaves too many details undefined.

Each opening should have an identification number linked to the drawings and quotation. The product schedule should state:

• Product series and model

• Opening method and direction

• Finished dimensions and quantity

• Frame and sash construction

• Thermal-break construction, where applicable

• Glass composition

• Hardware configuration

• Seals and drainage details

• Surface finish and color

• Screens and accessories

• Relevant dimensional and weight limits

Use written specifications to confirm the proposal. Descriptions such as “premium glass,” “German hardware” or “high-performance frame” should be supported by exact product information.

Changes made during design development should be recorded in the revised schedule before production approval.

5. Check Performance Reports Against the Proposed Product

A performance value is useful only when buyers understand what was tested and how the result relates to the proposed configuration.

Request the original report or a sufficiently complete copy showing:

• Report number and issuing laboratory

• Product identification

• Tested dimensions and opening type

• Frame, glass and hardware configuration

• Test standard and method

• Test date and measured results

• Relevant limitations or observations

Check whether the proposed product matches the tested assembly. If dimensions, glazing, hardware or construction differ, ask for an explanation of how the evidence applies.

A report for one casement window should not automatically be used to represent every sliding window, door or oversized opening in an order.

The project’s technical adviser should assess whether the documentation is sufficient for the specified application.

6. Distinguish Product Testing from Certification

Testing and certification should be evaluated separately.

A laboratory report describes the results of a defined test. A certification may cover particular products, configurations, manufacturing arrangements or ongoing assessment requirements.

When a supplier refers to certification, request:

• The certificate or approval number

• The issuing organization

• The certificate holder

• Covered products and configurations

• Validity and current status

• Applicable limitations

Where an official directory is available, check the entry directly.

Do not assume that a company-level certificate establishes every product’s thermal, acoustic, structural or destination-market compliance. Likewise, participation in drafting a standard does not replace evidence for the product being purchased.

7. Review Samples and Project Mock-Ups

A sample can help buyers assess appearance, assembly and operation before approving a larger order.

Inspect the surface finish, corner joints, glass appearance, seals, handles, locking and opening movement. Check the proposed screen and accessory arrangements where relevant.

Record the approved sample’s configuration and any agreed corrections. The purchase documents should explain how the sample relates to the production order.

For larger projects, a representative mock-up may also help the project team review installation details and coordination with the wall opening.

However, visual inspection and smooth operation do not establish thermal, acoustic, water or wind performance. Supporting technical evidence remains necessary.

8. Compare Quotations Using the Same Scope

Two quotations can appear similar while including different glass, hardware, finishes or delivery responsibilities.

Before comparing prices, confirm whether both proposals cover the same product schedule and supply scope.

Check the inclusion of:

• Glass and hardware

• Screens and accessories

• Special finishes

• Shop drawings

• Export packaging

• Inspection

• Freight and insurance

• Import charges and taxes

• Installation support

• Replacement parts

Ask each supplier to identify exclusions clearly.

A price per square meter can be useful for preliminary budgeting, but the final comparison should be based on the actual opening schedule and agreed configuration.

The contract should also explain how design changes, quantity changes and substitutions will affect the price.

9. Approve Drawings Before Production

Drawings should connect the architectural requirements with the products being manufactured.

Review opening dimensions, frame dimensions, opening direction, glass arrangement, handle positions, thresholds and installation details.

Confirm which measurements the supplier has used and who is responsible for checking them.

The production approval should identify the final drawing revision, product schedule, colors, glass and hardware. If a proposed substitution becomes necessary, require written approval before it is implemented.

Keeping a clear revision record helps prevent production based on an outdated quotation or drawing.

10. Define Inspection, Packaging and Delivery Arrangements

Agree on the quality checks that will take place before shipment.

Depending on the order, inspection may cover dimensions, finish, glazing, hardware, operation, labeling, quantities and packaging.

For mixed orders, package labels should correspond to the opening schedule so that products can be identified at the destination.

Ask how fragile components will be protected and how the packaging supports the intended handling and transport arrangements.

The contract should establish:

• Production and shipment milestones

• Agreed delivery terms

• Responsibility for transport and insurance

• Required shipping documents

• Inspection arrangements

• Procedure for reporting damage or shortages

Delivery timing should account for the agreed production scope, transport route and destination arrangements.

11. Clarify Installation and Warranty Responsibilities

The supplier, importer, installer and building contractor may have different responsibilities.

Before ordering, establish who will handle site measurements, installation drawings, anchoring, perimeter sealing, waterproofing, adjustment and final inspection.

Request written installation guidance for the selected product where available.

Warranty terms should identify the responsible company, coverage period, exclusions and claims procedure. Confirm whether coverage applies to the frame, glass, finish, hardware, installation or a combination of these.

For overseas projects, also ask how replacement parts will be identified, supplied and delivered.

A written warranty with a workable support process is more useful than a general promise of lifetime service.

12. Preparing a Feiyu Project Enquiry

To prepare a Feiyu enquiry, send the project location, drawings, opening schedule, dimensions, preferred opening methods and required performance.

Ask for a proposal identifying the recommended product model and configuration, supporting documentation, supply scope, delivery arrangements and warranty terms.

If a requirement has not yet been established, identify it as an open question rather than assuming that a general catalogue description satisfies the project.

The final order should be based on the approved drawings, technical schedule and written agreement.

Frequently Asked Questions

Is a well-known brand enough to establish product quality?

Brand background can help with supplier research, but buyers still need to verify the exact product, manufacturing responsibility, documentation and support arrangements.

Can one test report cover an entire order?

That depends on the products, configurations and applicable rules. Ask the supplier to explain the scope of the evidence, and have the project’s technical adviser assess its suitability.

Should I request a sample before ordering?

A sample can help evaluate finish, assembly and operation. Its usefulness depends on how closely it represents the proposed products. It does not replace performance testing.

What should I check before paying a deposit?

Confirm the contracting company, payment recipient, product schedule, drawings, delivery scope, payment conditions and warranty. Resolve important uncertainties in writing.

What if the supplier changes a component?

Request the proposed change in writing. Review its effect on appearance, operation, performance, documentation, price and delivery before approving it.

Final Checklist Before Ordering

Before authorizing production, confirm that you have:

1. Verified the contracting and manufacturing companies

2. Approved the product schedule and drawings

3. Reviewed applicable reports and certificates

4. Confirmed any sample or mock-up requirements

5. Agreed on inspection and packaging

6. Defined delivery and installation responsibilities

7. Obtained written warranty terms

8. Recorded the final price, exclusions and payment conditions

A documented purchasing process helps buyers understand what they are ordering and gives all parties a clearer basis for production, inspection, delivery and support.