How to Compare Aluminium Window Suppliers in China Beyond Unit Price

A useful supplier does not start by pushing one series for every opening. They ask about building type, location, opening size, glass target, use frequency, screen requirement, finish and packing. That questioning habit is a good sign because aluminium windows are project products, not single catalogue items.

If two suppliers quote the same opening with very different prices, check whether they are quoting the same frame depth, glass, hardware, screen and packing scope before deciding who is expensive.

A low unit price can hide missing glass, weak hardware, different finish, no screen, basic packing or unclear accessory handling. Ask for the quote to separate product series, glass build-up, colour, hardware, screen, drainage notes, packing and trade term.

For builder orders, it is also helpful to separate repeated openings from special items. Large doors, corner windows, sunroom pieces and motorized windows should not disappear inside one average price.

The drawing review process tells you how the supplier will behave after the deposit. A serious team will mark missing sizes, unclear opening direction, large-panel concerns, glass weight questions and packing needs before production.

If the supplier only replies with a fast price and no questions, the early experience may feel easy, but the hidden decisions still exist. Those decisions often return later as changes, delays or mismatched expectations.

Quotation review example: deciding where five folding-door panels will stack (preliminary budget; anonymised).

This anonymous YULUX budget covered one folding door measuring 4,300 × 2,100 mm, with five panels preferred. Two existing-door photographs retained with the quotation show dark glazed frames, an exterior terrace and the connection between the interior and exterior. The dimensions and panel preference come from the enquiry record and quotation; they were not measured from the photographs.

Five panels leave decisions to make — Black powder coating and clear glazing were proposed, but the stacking side and opening direction were still awaiting confirmation. The drawings need to show where the panels stack, which way the door opens and the final hardware arrangement. The budget did not treat any particular stacking arrangement as agreed.

For a similar replacement enquiry, existing-site photographs can help identify space to retain, objects beside the door to avoid and a preferred stacking position. Record those requirements in dimensions and an opening diagram. Photographs provide context but do not replace a site measurement.

Compare the selections and exclusions together — The quotation provisionally specified 6 mm clear toughened safety glass. The final safety-glass specification remained subject to review against the applicable project requirements; the quoted description was not a completed compliance assessment. The exact black colour reference and gloss level were also pending, as was the final hardware.

Insect screens were excluded from this budget. Any screen requirement would need to be discussed alongside the door rather than assumed to be included. The document placed production drawings after written order confirmation. Site measurement, installation and local engineering were outside the default scope unless expressly included.

These details give a buyer concrete items to compare against another offer: the same dimensions, panel arrangement, glass, finish, screens and site-work scope. The photographs show the existing door, and the available record remains at the budget stage. It does not establish that YULUX completed the replacement or installation.

For your enquiry: Send the existing opening dimensions and photographs with your preferred stacking side and opening direction. Ask each supplier to return an opening diagram and to mark glass, colour, gloss, hardware, screens and site work as confirmed, excluded or still to review.

Quotation review example: 26 lines, 28 items and a 10 mm question (preliminary budget; anonymised).

One anonymous YULUX quotation brought sliding windows, tilt-and-turn windows, fixed glazing, heavy-duty sliding doors, hinged doors with upper opening windows and motorised roller-shutter combinations into a single schedule. It contained 26 quotation lines covering 28 items. Roller shutters included within window combinations were not counted as additional standalone items.

Keep the configuration beside each opening — The different opening types appeared as separate items. Each could be checked by its reference, dimensions, quantity and operating arrangement rather than being reduced to one average square-metre price. For a window-and-shutter combination, the inclusion of the shutter also matters when comparing counts and scope.

The two-panel sliding-window item proposed 5 + 15 + 5 Low-E double glazing, a concealed two-point lock, sliding rollers and an insect screen. The inward tilt-and-turn item proposed 5 + 20 + 5 Low-E double glazing, concealed tilt-and-turn hardware, multi-point locking and an insect screen. These were quotation specifications, with the final glass build-up subject to project confirmation. The final RAL colour was pending as well.

Those configuration descriptions do not establish tested thermal or acoustic ratings. The commercial scope also needed a separate comparison: export packing was included, while site installation, local works, international freight, duties, taxes and clearance were excluded.

Leave conflicting dimensions visible until they are resolved — Opening A16 recorded section widths of 3,880 mm and 2,480 mm alongside an overall width of 6,350 mm. The original enquiry drawings retain the corresponding inconsistent overall and section annotations at A16 and A27, and the quotation references those original drawings.

Using the quotation’s millimetre dimensions, 3,880 + 2,480 = 6,360 mm: a 10 mm difference from the stated 6,350 mm overall width. The quotation explicitly left the final joined widths pending confirmation. It does not establish which width is correct or whether a joint allowance explains the difference.

The overall width, section widths and joining arrangement need to be reconciled before they become manufacturing instructions. At this stage the quotation is a review record with visible questions, not evidence of production, delivery or completed installation.

For your enquiry: Compare every offer against the same drawing revision and opening marks. Keep differences in dimensions, glass, hardware, finish, accessories and exclusions in a written clarification list, and request a revised quotation and drawing when an answer changes the scope.

International window orders need more than finished frames. Ask how frames are protected, how glass corners are separated, how accessories are packed, how labels match the schedule and whether loading photos can be provided.

Packing is not decoration. It affects whether the buyer, builder or warehouse can receive, identify and move the order without confusion. This is especially important for mixed-size villa packages and large sliding doors.

Fast replies are useful, but the quality of the questions matters more. A supplier who asks about project country, drawings, glass, hardware, finish and packing is usually trying to protect the quote scope. A supplier who never asks may be quoting from assumptions.

Compare the price and how well the supplier helps you turn an unclear project into a clear order package.