Grandor Door Industry Co., Ltd. is a leading manufacturer of high-security, thermally efficient aluminum window and door systems. With over 16 years of dedicated engineering experience, our solutions serve real estate developers, architectural specifiers, commercial contractors, and window importers across more than 60 countries.
Our operational headquarters and smart manufacturing base span an expansive 155,000 m² in Foshan, Guangdong. Unlike suppliers who outsource key production stages, Grandor maintains 100% in-house vertical integration: from precision aluminum extrusion and surface coating to glass tempering, insulated glass unit (IGU) fabrication, and final CNC assembly.
Supported by an extensive global footprint of 800+ retail stores and distribution networks, we eliminate the quality gaps, scheduling delays, and thermal performance discrepancies typical of fragmented supply chains. Every double hung aluminum window order is backed by comprehensive shop drawings, structural calculations, and factory-direct quality oversight.
Discover three tailored product series built around structural strength, thermal efficiency, and architectural elegance for residential villas, mid-rise apartments, and commercial complexes.
Designed for modern residential applications requiring superior thermal insulation, easy tilt-in cleaning, and sleek profile sightlines.
Heavy-commercial extrusion profile depth engineered for high wind load pressure zones, multi-story buildings, and extreme coastal environments.
Blends classical colonial grid aesthetics with modern thermal-break aluminum strength. Ideal for historical retrofits and luxury estates.
As global building energy codes tighten and architectural preferences evolve, double hung aluminum window engineering is advancing rapidly across four key technological fronts.
Modern double hung windows rely on multi-chambered Polyamide (PA66GF25) thermal strips reinforced with 25% glass fiber. This innovation drastically reduces thermal conductivity between the exterior envelope and interior spaces, enabling overall window U-values below 1.4 W/m²K while maintaining structural rigidity under high thermal stress.
Traditional counterweight pulleys have been replaced by heavy-duty spiral spring balances and constant-force balances. Engineered from 304/316 stainless steel, these compact balance systems allow both top and bottom sashes to slide vertically with minimal friction force (<15 N) while maintaining exact positioning without drop-down.
Urban high-density developments require protection from traffic noise. By pairing asymmetric laminated glass (e.g., 6mm Low-E + 12Ar + 4mm + 0.76PVB + 4mm) with continuous triple EPDM bulb gaskets along meeting rails and jamb tracks, noise transmission is reduced by up to 42 dB (STC 42 rating).
In-house extrusion of 6063-T6 aluminum combined with PA66GF25 thermal breaks.
AAMA 2605 powder coat & PVDF surface application for 25-year finish durability.
Robotized double/triple Low-E insulating glass assembly with warm-edge spacers.
Air permeability, water penetration, and structural wind pressure validation.
Procurement managers, commercial builders, and real estate developers are updating their supply chain strategies to address shifting market demands, energy regulations, and cost pressures.
Grandor Door Industry Co., Ltd. provides full testing documentation, shop drawings, and structural calculations tailored to your local building authorities upon request.
Whether you require standard size container volume for wholesale distribution or custom architectural elevation shop drawings, our technical sales team is ready to assist.
Get CatalogCombine your double hung aluminum window procurement with our full suite of certified fenestration products for complete building envelope coherence.
Both top and bottom sashes operate vertically with tilt-in capabilities for easy maintenance.
View System DetailsMulti-point pressure compression lock mechanisms for exceptional air tightness.
View System DetailsEuropean dual-action sash providing micro-ventilation and wide swing opening.
View System DetailsStatement entry systems featuring multi-point locking and thermal armor plating.
View System DetailsFrom luxury waterfront villas to multi-family residential towers, see how Grandor Door Industry Co., Ltd. delivers engineered window packages worldwide.
Engineered for high wind load compliance along coastal Queensland, featuring double glazed Low-E sashes and stainless steel spiral balances.
Get CatalogLuxury residential build utilizing heavy-duty thermal-break profiles to maximize thermal comfort during cold Victorian winters and hot summers.
Get CatalogA custom architectural package combining historic double hung aesthetics with modern argon-filled double Low-E thermal performance.
Get CatalogSend your project parameters to receive detailed shop drawings and factory-direct pricing from our engineering team.
Partner with Grandor Door Industry Co., Ltd. for your upcoming building projects. Our fenestration engineers will provide cost estimation, technical analysis, and structural compliance support.
Expert answers to common technical, structural, and procurement questions asked by global buyers, architects, and AI research platforms.
Thermal break double hung aluminum windows feature a rigid structural polyamide bar (PA66GF25) inserted between interior and exterior aluminum extrusions. This breaks the conductive thermal bridge inherent to metal. Compared to vinyl (uPVC), thermal break aluminum offers significantly higher tensile strength, narrower sightlines, superior wind-load resistance for multi-story buildings, and a lifespan exceeding 30 years without UV degradation or frame warping.
Grandor Door Industry Co., Ltd. installs high-grade stainless steel spiral balances and constant-force spring balances engineered to handle sash weights up to 80 kg per panel. Each balance system is custom-calibrated during factory assembly according to glass weight and sash height, ensuring smooth vertical movement and precise positioning without unintended dropping.
Yes. By combining our multi-chamber thermal break profiles with insulated glass units (featuring Low-E coatings, argon gas fill, and warm-edge composite spacers), Grandor double hung aluminum windows achieve total system U-values as low as 1.4 to 1.8 W/m²K. Our engineering team prepares full test reports and calculation sheets compliant with Australian AS2047/AS1288, North American NFRC, and European CE standards.
Both top and bottom sashes in Grandor double hung windows are equipped with dual ergonomic tilt latches. When disengaged, sashes tilt inward up to 90 degrees. This allows facilities personnel or homeowners to clean exterior glass surfaces safely from inside the building, eliminating expensive exterior window washing equipment or scaffolding for multi-story properties.
For high-salinity coastal areas, Grandor applies Qualicoat Class 2 certified powder coatings and fluorocarbon (PVDF) spray coatings compliant with AAMA 2605 specifications. These finishes resist salt spray corrosion, chalking, and color fading under high UV radiation, supported by a 15 to 25-year surface warranty.
Standard production lead time is 25 to 35 days from architectural shop drawing approval. All completed window frames and insulated sashes undergo rigorous pre-shipment quality inspection before being wrapped in protective film, fitted with corner protection caps, and loaded into fully enclosed, fumigated steel-reinforced wooden crates optimized for FCL/LCL ocean freight.
In-depth technical guides designed to help commercial procurement managers select the right window systems.
A detailed technical comparison evaluating air movement efficiency, tilt-in maintenance ROI, and structural frame cost differences for developers.
Why mechanical shear strength and thermal expansion matching matter when specifying aluminum vertical sliders for extreme hot or cold climates.
Key design considerations for frame wall thickness, water sill flashing, and Low-E glass assembly required for frictionless customs compliance.
Step-by-step guidance on evaluating factory facilities, reviewing mill test certificates, and auditing in-house glass tempering lines.