Broken-Bridge Aluminum Multi-Cavity: Core of High-Performance Custom Windows & Doors

1. What Is the Multi-Cavity Structure in Custom Windows and Doors (for Novice Renovators)?​

Many homeowners get confused by the term “multi-cavity” when choosing custom windows and doors — in fact, it refers to multiple independent square cavities partitioned within the profiles of broken-bridge aluminum custom windows and doors, like a string of side-by-side small compartments. These cavities completely block air and heat exchange between the inside and outside of the profiles. Currently, the mainstream designs on the market are 3-cavity, 4-cavity, and 5-cavity structures, which are key to determining the performance of custom windows and doors. However, more cavities do not equal better performance.​

2. Multi-Cavity Structure: 3 Core Advantages of Custom Windows and Doors​

1. Extreme Thermal Insulation, Adapting to Diverse Customization Needs​

Each cavity acts as a natural thermal insulation barrier. When custom windows and doors are paired with filling cotton, the heat transfer coefficient (K-value) can be as low as 0.8W/(㎡·K), making them 50% more energy-efficient than ordinary broken-bridge aluminum products. Homeowners in northern regions who choose this configuration can reduce winter heating costs by 20%; those in southern regions can block outdoor heat waves and lower air conditioning energy consumption through customization.​

2. Effective Sound Insulation, Meeting Quiet Customization Scenarios​

Sound waves are repeatedly refracted and weakened when passing through multi-cavities. When custom windows and doors are combined with sound insulation cotton, they can achieve an additional noise reduction of 10-15dB. For street-facing properties that customize such windows and doors, a library-level quiet environment (around 35 decibels) can be achieved — especially suitable for families with the elderly or children to customize.​

3. Superior Wind Pressure Resistance & Durability, Adapting to Complex Customization Environments​

The “mechanical support network” formed by multi-cavities disperses external forces. If broken-bridge aluminum custom windows and doors use profiles with a wall thickness of 1.8mm, their wind pressure resistance level can reach Grade 9 (the highest national standard), capable of withstanding the impact of Level 12 typhoons. This configuration is a safer choice for customizing windows and doors in coastal areas.​

3. How to Choose the Number of Cavities? 2025 Latest Selection Table for Custom Windows and Doors​

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Number of Cavities​	Core Performance (2025 Actual Test Data)​	Suitable Customization Scenarios​	Customization Notes​
3-cavity​	K-value ≤ 2.0, Wind Pressure Resistance Grade 7​	Custom windows and doors for low-rise residences, customized for mild inland areas​	Basic sealing technology is required during customization​
4-cavity​	K-value ≤ 1.5, Wind Pressure Resistance Grade 8, Noise Reduction 30dB​	Custom windows and doors for mid-rise residences, customized for street-facing properties​	It is recommended to choose profiles with a wall thickness of ≥1.6mm for customization​
5-cavity​	K-value ≤ 1.0, Wind Pressure Resistance Grade 9, Noise Reduction 35dB​	Custom windows and doors for high-rise buildings, customized for coastal typhoon-prone/cold regions​	Glue injection technology must be used to prevent deformation during customization​

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4. Pitfall Avoidance Guide for Custom Windows and Doors: Don’t Fall for These Misconceptions!​

Q1: When customizing windows and doors, more cavities mean better performance?​

No! Beyond 5 cavities, the weight of custom windows and doors profiles increases sharply. If the wall thickness is less than 1.8mm, the profiles are more likely to break in strong winds. Industry tests show that blindly increasing the number of cavities also causes the cost of custom windows and doors to soar by 40%, resulting in extremely low cost-effectiveness.​

Q2: For high-rise custom windows and doors, is a 5-cavity structure enough?​

No! When customizing broken-bridge aluminum windows and doors in high-rise buildings in coastal areas, in addition to choosing a 5-cavity structure, reinforced mullions must be added and reinforced with glue injection pin technology — this technology can increase the deformation resistance of custom windows and doors by 25%, completely solving water leakage problems during typhoons.​

Q3: Should the cavities of custom windows and doors be filled with materials?​

Absolutely! The K-value of empty cavities is as high as 3.0. When custom windows and doors are filled with polyurethane, the K-value can be reduced to 1.5, doubling the thermal insulation performance; for street-facing properties, filling with sound insulation cotton during customization will significantly improve noise reduction effects, avoiding the need for additional sound insulation modifications later.