Solarlux Megaline reviewed – a bifold door like no other

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Nick Dardalis

Solarlux can be credited with inventing the modern bifolding door and already makes high-end bifolds in terms of design and quality. The new Solarlux Megaline takes what can be done with an already exceptional aluminium bifolding door to new levels. Megaline is unique in providing a bifold solution on projects where a sliding door was previously the only option. Megaline has the same sophisticated Solarux engineering, excellent build quality and features you won’t find on other bifold door brands.

What is the Solarlux Megaline bifold door?

solarlux megaline bifold doors
The Solarlux Megaline Bifolding Door
solarlux glass room6

The new Solarlux Megaline takes what can be done with other aluminium bifold doors to new levels with heights up to 4.5m

Editor's Rating:


  • A technically superior bifold door
  • The 4.5m maximum panel height
  • Six floor track options
  • Does more than a sliding door


  • The long lead times
  • The transom on doors over 2.55m
  • Only 900mm wide panels at the tallest sizes
  • Technical limitations of larger panels

The Solarlux Megaline is a specialist aluminium bifold added to the seven other models available from Solarlux. The purpose of Megaline is to provide a bifolding door solution where previously only a large-span sliding door was possible. The standout feature of Megaline is its maximum panel height of 4.5m.

Tall bifold doors are not exactly new. Several models already reach 3m tall, with Sunflex and Solarlux having models going up to 3.5m tall.

You may think there isn’t a market for ultra-tall doors – there is. Several high-end sliding door brands such as Panoramah, Cortizo, Hyline and Solarlux’s own spectacular sliding door called cero are all capable of heights over four metres. And these ultra-tall doors are not a new phenomenon, frequently showcased in programmes such as Grand Designs, one being a refurbishment of a London water tower into a dwelling ten years ago.

Megaline is designed for architect-designed new extensions, has the facility to slide and fold inside or outside and comes in all the configurations of a regular bifold door. Above all, Megaline finally gives architects and their clients a bifold solution until now was not available.

The design of the Solarlux Megaline

As you’d expect from a bifold designed for the most modern new build homes and ambitious extensions, the frame styling is just as modern.

With the door intended for large size, invariably, this comes with technical limitations depending on whether it’s double or triple-glazed.

The 4.5m high capability is only possible on double-glazed doors, and the panels can only be up to 900mm wide. Triple-glazed doors go up to 3.6m maximum height and can only be up to 1100mm wide.

The bifold panels can also go up to 1.5m wide, but only on a double-glazed door and up to 2.3m high. A triple-glazed door goes up to 1.1m maximum width and up to 2.2m high. So the taller you go, the narrower the doors and the wider you go, the shorter the doors must be.

There’s another technical or structural limitation with these doors, which concerns heights over 2.55 metres. You may need to split the glass with a transom in the door panel. The main reason to split the door panel is the glass weight and the maximum size a double-glazed unit can be. So this is not entirely a bad design – it’s incredibly difficult to find glass sheets at more than four metres.

It’s also worth remembering the structural calculations required when creating any large glass product; wind forces, weather impact and security are all factors affecting what is technically possible. A large door in a property by the sea will experience greater forces than one at the back of a house in a city.

The taller the panels and the greater the wind-loading, it’s the hinges that are designed to take the strain. Stacking several hinges above each other makes it possible to create the required strength. For doors subjected to the highest levels of weather or wind, additional structural profiles in the panel joint areas create the right amount of stability.

The frames are thermally insulated, as you’d expect from an advanced bifold system. Unlike other bifold doors using a more conventional thermal break, Solarlux’s own bionicTURTLE® has several additional functions in addition to insulating the aluminium; thinner profiles, door stability and providing location points for locking systems are all part of the bionicTURTLE® design.

Solarlux offers more bifold track options than other bifolds, and Megaline is no exception. Six different tracks create all manner of functional solutions depending on where the door is located and how it’s used.

The tracks meet fully weathered requirements, completely flush floors, ramp-type for wheelchair access and even a minimalist, barely visible design with a 14mm step. Another example of how Solarlux engineers their bifold better. Just like the Ecoline product, these come with neat track covers keeping the tracks cleaner and protecting them from impact. You can even put LED lighting creating a feature of the door track at night.

The aesthetics of the Solarlux Megaline

The outer frame, track and folding sashes all have a completely flat appearance o the inside or outside faces and a neat rebate around the frame where the doors close against the frame for sealing and security.

Frame covers are another feature within the Megaline, creating a better-looking door when the panels are fully folded back.

Technical information

The full technical information is available on the Solarlux website or via one of the Premium Partners. Solarlux Megaline has the following key features, aside from the impressive door sizes:

  • Tested to numerous standards, specifically DIN and ISO
  • Class B4 wind resistance, the maximum performance for sliding doors
  • Class 3 air permeability for airtightness, again a good result
  • Class 7 water tightness, one of the top water pressure classifications

Bifold door hardware

The design features in other Solarlux bifolds find their way to this model too. Solarlux designs and patents its own hardware, whereas many other bifolds use industry-wide components. The oversize requirements placed on this door also call for alternative rollers and components, again all created to give this door reliable operation every time. You can see the thought that goes into what Solarlux designs. The bifold pull handles contain a small rubber element designed to protect the paint finish when the bifold handle makes contact with the paint finish.

Handles and hardware only come in one style but in our experience with these doors and seeing them in showrooms and customer homes; they look in keeping with the overall styling of the products. Given the nature of these doors, locks also come with the facility to route cables through the profiles that connect to building alarms or monitoring systems.

The sliding folding hardware is also designed for easy-running and low wear. Most noteworthy the rollers don’t need guide carriages, making this visible hardware look much neater than other regular bifold rollers.

Security of the Solarlux Megaline

The security you get with Solarlux Megaline will usually depend on the overall specification, given the large possible sizes and how the doors engage at the uppermost position. As standard, you get multi-locking points, security hardware, internal glazing beads and other protection features. Of course, the monitoring facility further adds to the enhanced security possibilities, as does the use of glass upgrades, such as laminated glass.

U-Values and Energy-Efficiency

The best available U-Values are 0.9Wm2k, exceeding Building Regulations. U-Values will vary depending on the door configuration and glass specification used.

Other products to compare with Solarlux Megaline

solarlux megaline in a glazing showroom

The technical capability of Megaline means there’s little to compare with it, but it ultimately depends on your project’s design and how tall your doors are required.

Solarlux’s innovative Megaline product opens the door to new element heights and widths therefore, there is little right now to compete with it. However, the following products can be considered where door panels don’t need to go up to the maximum height.

Solarlux Highline is another superb, more standard bifold by the company with gorgeous 99mm sightlines and can go up to 3.5m.

We’ve already reviewed the latest new Schüco bifold and there’s a new model coming soon with even better credentials and with panel sizes up to 3.5m high.

The Sunflex SF range can achieve 3.2m or more and is a Made-in-Germany bifold, another high-end folding sliding door.

Anyone considering a structural opening designed to take oversize doors will be best served by Megaline as it’s the only door right now of its type.


Solarlux Megaline is unique, exclusive and altogether different. Its market position is to provide a folding door solution for outstanding homes and extensions where the project is not constrained by budget. It pushes the limits of what is technically possible with a folding sliding door and comes from arguably the best bifold doors.

We’ve seen the earlier version of a supersize bifold in the Solarlux showroom in Welwyn Garden City, so the company has effectively introduced a new version with Megaline.

Solarlux Megaline brings new design solutions for architects and their clients wanting a door designed to do more than the regular glazing systems designed for standard openings and properties. You can visualise this product spanning the ground and first floor of a contemporary home, effectively opening up an entire elevation better than sliding doors with the same size capability. It’s also ideal for homes designed with very high ceilings. There’s nothing on the market like Solarlux Megaline.

Where to buy or enquire about Solarlux Megaline

Only Solarlux makes its doors, and all products are available through a network of Solarlux Partners. You can get in touch for more information about the product and where to arrange a viewing, a consultation or a quotation.