One name can hide three different products
In sales conversations, very different constructions are often grouped under the label “sliding door”. HST lift-slide, PSK parallel-slide/tilt systems and simpler conventional sliders use different mechanisms and have different limits. If those differences are not explained, quotations may look inconsistent even though they describe products from different performance classes.
Start with the intended use: a large terrace portal, a medium opening that is used occasionally, or an economical sliding closure. That choice changes expectations for threshold height, sealing, sash weight, operating comfort and price.
HST: large glazed panels that still move comfortably
In an HST system the handle lifts the sash away from its seals before the sash runs along the track. This makes it possible to move large and heavy glazed panels with relatively little effort. HST is a natural choice for wide terrace openings, panoramic glazing and designs that seek large glass areas with few vertical divisions.
Systems may use multiple tracks and different combinations of fixed and moving panels. Pricing therefore cannot be based on square metres alone. Track count, sash type, overlaps, meeting profiles, threshold, hardware and glass weight all influence both construction and cost.
PSK: the sash moves out, then runs parallel
PSK hardware pulls the sash out of the frame plane and then guides it parallel to the fixed section. Many variants also allow tilt ventilation. The concept is often based on conventional window profiles and can be less expensive than HST.
Operation is more complex, the threshold is usually less seamless and size and sash-weight limits are lower. For medium openings PSK can be an excellent compromise, but it should not be sold as an equivalent to HST when the project calls for very large panels and effortless daily operation.
Conventional sliders: simplicity still has a role
Simpler sliding systems move along tracks without a lift or tilt-slide mechanism. They can be rational for less demanding positions, auxiliary spaces, balcony enclosures or markets where simplicity and price matter more than the highest sealing performance.
Be transparent about performance. Brush seals and the construction of a basic slider do not normally provide the same airtightness as a high-quality HST or tilt-turn element. The right product is the one that matches the exposure and use case, not the one with the most impressive name.
Five questions before choosing a system
Define the clear opening, desired panel sizes, operating frequency, threshold requirement and expectations for air and water tightness. Then verify glass weight limits, the opening scheme, insect-screen or shutter integration, drainage details and installation conditions.
Once those facts are in the quotation, HST, PSK and conventional sliders stop being confusing acronyms. They become three clear technical answers to three different sets of needs.
