13/03/26

Silent Barrier: Role of Seals in PVC Windows

The seal in PVC windows is an inconspicuous yet critically important element that creates a tight barrier between the interior and the outdoors. It largely determines thermal and sound insulation, as well as protection against dust and draughts. Imagine this: even a perfect window with flawless hardware won’t fulfil its purpose without a high‑quality seal — heat will escape through micro‑gaps, and noise and cold air will get in.

Modern seals are made from various materials, most commonly EPDM (ethylene propylene diene monomer rubber), TPE (thermoplastic elastomer) or silicone. EPDM stands out for its high elasticity and resistance to temperature fluctuations. TPE holds its shape well and is durable, while silicone seals are renowned for their exceptional resistance to UV radiation and frost.

The seal is installed along the entire perimeter of the sash and frame, following their contours. When the window closes, it gently compresses to fill the smallest irregularities, then recovers its shape — this creates a tight yet elastic contact. Thanks to this, warmth stays inside during winter, heat stays out in summer, and street noise remains outside the apartment.

The service life of a seal depends on the material quality and maintenance: on average, it lasts 10–15 years. To extend its lifespan, simply clean the surface from dirt a couple of times a year and treat it with a special silicone lubricant. This way, the window’s unnoticeable “guardian” will last longer and keep reliably protecting your comfort.