Refrigerator Technology “Crosses Over” into Windows and Doors—How Is Full-Cavity Filling Revolutionizing Traditional Soundproof Windows?

Who says doors and windows are all hollow? Womusen offers a revolutionary solution—applying food-grade thermal insulation and soundproofing technology, originally used in refrigerator doors, to doors and windows.

Traditional thermal-break aluminum door and window profiles feature a hollow internal structure. When external noise enters, sound waves vibrate and are rapidly transmitted through the metal profiles, creating resonance much like “ringing a bell,” while heat is also quickly lost along the metal bridge. This is why many windows, even when equipped with double-pane glass, still emit a low-frequency “hum” when closed—the profiles themselves are transmitting sound.

How does the full-cavity filling technology solve this problem?

The core of this technology lies in injecting high-density polyurethane foam into the interior of multi-chamber thermal-break aluminum profiles to achieve complete cavity filling. Polyurethane itself has an extremely low thermal conductivity (0.022–0.030 W/m·K), far superior to that of air and common filling materials; it is a top-tier insulation material used in refrigeration equipment such as refrigerators and cold storage facilities. At the same time, it is a first-rate damping and sound-insulating material. With its closed-cell foam structure, it possesses excellent sound absorption and sound wave blocking capabilities.

When sound waves attempt to propagate through the profile, the high-density polyurethane foam acts like “sound-absorbing sponge,” fully absorbing and dissipating the vibrational energy, thereby physically blocking the sound’s transmission path. After curing, the polyurethane foam fills the cavity, enhancing the overall structural stability of the profile and mitigating minor deformations caused by thermal expansion and contraction. It also offers excellent resistance to aging and moisture and heat, with a service life that matches that of the doors and windows themselves.

What benefits does this technology offer?

Significantly improved sound insulation: When combined with laminated double-pane glass, the entire window can achieve sound insulation of over 45 decibels, reducing noise to library-level standards (25–35 decibels) the moment the window is closed;

Enhanced thermal insulation: The window’s U-value can be as low as 1.2 W/(m·K), helping users save approximately 30%–50% on annual heating and cooling costs;

Greater structural stability: The filled profiles offer enhanced resistance to deformation, extending the service life of doors and windows.

“Transplanting” the insulation and soundproofing technology from refrigerators to doors and windows is not merely a conceptual transfer, but a systematic upgrade—from materials to structure.