17/01/26

Functions of Seal in PVC Window

The seal is an inconspicuous yet critically important component of a PVC window. It is an elastic strip made of polymer material, installed around the perimeter of the sash and frame. Its primary purpose is to ensure a tight closure and eliminate unintended gaps.

The main function of the seal is sealing. It prevents cold air, precipitation, dust, and outdoor noise from entering. Thanks to this, a comfortable indoor microclimate is maintained, and energy losses through the window are minimized.

Moisture protection is equally important. The seal prevents water from seeping into the joints between the frame and sash, avoiding wetting of the installation joints and mold growth.

Another key role is sound insulation. A tight fit of the sash dampens sound waves, reducing outdoor noise levels inside the apartment.

Additionally, the seal cushions the impact when the sash is closed: it works as a shock absorber, reducing stress on the hardware and extending the window’s service life.

Over time, the seal loses its elasticity: it may crack, dry out, or deform. Therefore, it is important to inspect it regularly and replace it at the first signs of wear — otherwise, the window will start to leak, and noise and moisture protection will decrease.

A high‑quality seal and its proper installation are key to long‑lasting and comfortable use of a PVC window.