GS20 vs GS15: Comparing Two Premium Sliding Doors from Glideline

At Glideline, we are proud to manufacture what we think are two of the best sliding doors presently available. The GS20 and the GS15.  Both are ultra slim, high-performance sliding doors that comprise our enhanced engineering and design with an incredible quality and effortless sliding action and transitional movement. 

 If you’re trying to decide between the GS20 vs GS15 Sliding Doors, we’ve put together this helpful guide to help you decide and that explains both sliding doors in detail.

The ultra-slim sliding doors by Glideline 

Designed to provide you with a luxury sliding door experience, GS20 and GS15 sliding doors are outstanding.  Thermally insulated profiles, professionally applied colour finishes, advanced components and re-engineered by us to make them superior to other similar bonded sliding doors. 

Each system supports two, three, or four-panel doors. Pocket sliding and open corner options are available. GS15 offers the broadest range, including frameless bonded corners and U-shape designs.

GS20 is our tried and tested bonded sliding door and the best selling door in our overall collection of sliding doors for dwellings.

Experience unmatched minimalism with the GS15 Sliding Door, featuring an ultra-slim 15mm consistent sightlines for breathtaking, uninterrupted views. With hidden hardware, smooth gliding wheels, and premium thermal performance, it’s engineered for luxury, light, and limitless space. Available in custom finishes and multiple configurations, the GS15 is the ultimate statement in modern glazing.

GS15 uses 8mm glass as standard, offering strength and energy performance in a slim package. It helps achieve the door's overall U-value and allows slimmer spacer bars. GS20 is more flexible with glazing options starting with 6mm glass.

GS20 vs GS15 – The interlock sightlines

When it comes to choosing a sliding door based on the interlock dimension, the GS15 is the slimmest sliding door in the UK, with just a 15mm interlock. Sightlines are consistent across the frame, sash, and head, creating a balanced look. GS20 features a 20mm interlock and slightly wider surrounding profiles. But both doors are beautiful, elegant, minimal and desirable.

Design Consistency 

Another difference when comparing GS20 vs GS15 is how the doors look once installed and what kind of design aesthetic you’re looking for. The slimmer GS15 offers 15mm sightlines throughout. The result is a clean and uniform aesthetic.

GS20 retains its slim proportions but the surround frame is slightly thicker. If you're aiming for the most minimal visual presence, GS15 is the all-round thinner door.

Sliding doors with the best sliding action

At Glideline, we enhance and re-engineer the base Cortizo bifold to provide something unique, sophisticated and better than the standard Cor-Vision model.  Whether you choose the GS20 or the GS15, both models come with upgraded stainless steel wheels and stainless steel tracks.  

As a result, both GS20 and GS15 sliding doors provide a refined sliding experience. It’s only when you move these doors you appreciate their impeccable feel as you open and close them.

Flush Stacking Panels 

Glideline are the only UK manufacturer to offer this type of sliding door with an exclusive flush stacking design.

When open, the panels sit flush against each other. All other sliding door sit staggered and one panel in front of each other when fully open.  The flush stacking design is  available on two- and three-panel configurations for GS20 and GS15.  We encourage you to see the flush stacking in any of our dealer showrooms or in our factory and you’ll wonder why all doors don’t come like this.

Highly advanced Track and Drainage Design

We were the first UK manufacture to provide the most advanced track and drainage system on the Cortizo sliding door system.  But there are subtle differences between the two.

GS15 includes Glideline’s bespoke drainage and track system. This ensures reliable water management, even with 100% flush tracks. GS20 also has improved drainage and weather sealing over standard sliding systems, but GS15 offers more advanced protection by design.

But overall, if it’s the flattest possible sliding door track you need, GS15 offers the best of both worlds.

Cutting Edge Thermal Performance

GS15 achieves a U-value as low as 1.2 W/m²K with a 1.0 centre pane. It uses double glazing only, with slimmer profiles helping thermal efficiency. GS20 typically achieves 1.4 W/m²K depending on glass spec.  

Both sliding doors comfortably meet Building Regulations for new build and existing dwellings.

Advanced Sliding Door Security

 Whether you choose the GS15 or the GS20, both come with advanced multipoint locking systems, and high security key cylinder.  Safety glass comes as standard, upgradeable to laminated glass for even more protection.  And both doors, come with an advanced bonded construction meaning glass cannot be removed with conventional glazing beads.

GS15 comes with a hidden handle and flip locks. GS20 features a slim handle with a secure key cylinder. Both are strong and reliable.

Arrange a viewing of GS20 and GS15 sliding doors at our factory and showroom

 Our premium sliding doors offer homeowners one of the best sliding doors in the UK today, expertly-crafted, professionally installed and with a quality guarantee.  And the come in a choice of sizes, colours and configurations. We can even manufacture small versions as horizontal sliding windows. 

The best way to appreciate the engineering, quality, sliding action and beautiful styling is to see and experience GS20 and GS15 in person.

Both GS20 and GS15 sliding doors are available to view in our Great Yarmouth showroom and factory. Contact us to arrange a viewing.  Our doors are also available in retailer showrooms across the UK, contact us for details of your nearest showroom.