What to look for when choosing low-threshold windows?

Low-threshold windows, often also called patio windows, are characterized by a minimalist threshold that is almost at floor level. This eliminates the barrier found in traditional windows and doors, providing a smooth transition between the interior and exterior. This is especially important in spaces where freedom of movement is crucial, such as single-family homes, apartments, or public utility buildings.

1. Type of material

The material from which the window profiles are made affects durability, insulation, and aesthetics.

  • PVC – good quality-to-price ratio, high thermal insulation, moisture resistance, but less rigidity compared to aluminum.
  • Aluminum – modern look, durability, and lightness, ideal for large glazing.
  • Wood – aesthetic and ecological, but requires regular maintenance.

2. Opening system and sliding mechanisms

Choose the system that best suits your needs:

  • Lift-and-slide system (HS) – allows easy sliding of even large sashes. Ideal for wide patio transitions.
  • Tilt-and-slide system (PSK) – cheaper option, but requires more interior space for tilting and sliding the sashes.
  • Folding system – allows complete opening of the space by folding the sashes to the side.

3. Thermal and acoustic insulation

Low-threshold windows should provide adequate thermal comfort and noise protection. Pay attention to:

  • Heat transfer coefficient Uw – for energy-efficient buildings ≤ 0.9 W/m²K.
  • Acoustic insulation, especially in noisy locations.

Calculating thermal transmittance in windows

4. Threshold construction

A low threshold is a key feature of these windows:

  • Completely flush threshold – best in terms of aesthetics and comfort.
  • Minimally protruding threshold – cheaper option, still comfortable, but less flush.

5. Glass quality

Choose glass that suits your needs:

  • Low-emission glass – provides good thermal insulation.
  • Anti-burglary glass – increases security.
  • Sun protection glass – prevents interior overheating.
  • Increased acoustic insulation glass – important in noisy locations.

6. Water drainage system

Check if the water drainage system is well designed and if the threshold has proper seals.

7. Security

Pay attention to anti-burglary features:

  • Anti-burglary fittings (class RC2 or higher).
  • Multipoint locks.

8. Size and design

Choose a solution that fits the building's aesthetics, offering customization options (profile color, type of glass).

9. Warranty and service

Make sure the manufacturer offers a long warranty and service support. Choosing a reputable company is key to window durability.

10. Price

Compare offers from several manufacturers and choose a solution that combines quality with an affordable price.