Compact Topvex solution improves indoor climate in older Stockholm apartment building

Systemair delivered Topvex Air Handling Units with integrated smoke bypass to an residential building in Stockholm. The reason for this? Their compact design, energy efficiency, other features and us as a reliable partner.

Franska Bukten, Sweden

Limited space not a problem

It was possible to fit two Topvex AHUs with integrated smoke bypass in the attic of Nybrogatan 18, where space is limited, thanks to their compact frameless design giving a minimum footprint.

Delivered on one of Stockholm’s busiest streets

The Topvex AHUs could easily be split onsite for smooth unloading and transportation into the building, and then up to the attic. This, combined with Systemair’s accurate time-specific delivery, ensured that the whole operation went smoothly.

Plug-and play installation and commissioning, a Topvex feature

The Systemair Access Control System enabled plug-and-play installation and commissioning of the Topvex AHUs. Once installed, Access intuitive menus help the user create the perfect indoor climate.

Major improvement in air quality and ventilation

An example of the efficiency of the FTX system with Topvex is that residents report that when they take showers, dampness and mist disappear much more quickly than previously.


Pineridge Hollow

Buying customer

AB Franska Bukten, HVAC contractor


Nybroviken Property Association


Replacing existing natural duct ventilation system with a modern FTX system


Topvex TC70-L-HWH-S with built in smoke-bypass

About Franska Bukten

Franska Bukten is a Stockholm-based consulting and service company operating in the real estate sector. The focus is on energy and HVAC projects.

Started in 2008, today the company has around 40 employees working primarily with HVAC inspections, energy calculations, and ventilation service and contracts.

Projects are mainly in Stockholm, the surrounding municipalities, and the Uppsala area. Since 2015 Franska Bukten has had a local office in Sandviken, 118 miles north of Stockholm.

Topvex solution improves indoor climate in older Stockholm apartment building

In early 2023, following a mandatory ventilation inspection, Nybroviken Property Association needed to replace the existing natural duct ventilation system in its, Nybrogatan 18, property with a modern FTX system (exhaust and supply air ventilation with heat recovery). For this complex project they consulted Swedish HVAC contractor Franska Bukten.

As a trusted partner, Systemair was brought in by Franska Bukten at an early stage. Topvex Air Handling Units with integrated smoke bypass were chosen for their compact designs, energy efficiency, and other features. Today, thanks to the new system, the residents of Nybrogatan 18 are enjoying a much improved indoor climate.

Systemair is a trusted supplier. We have a good long-term relationship, tight communication, and we can rely on them to give us quick assistance on projects. We’re happy with their cooperation on all aspects of this project, from delivery to day-to-day communication.

Mikael Landgren
Project Manager, Franska Bukten AB

Replacing the existing natural duct ventilation system in Nybrogatan 18 with an FTX system called for a truly compact, energy efficient solution. Topvex was the obvious answer.

Sebastian Larsson
Sales Representative, Systemair Sweden AB

Solution supplied by Systemair

  • Topvex TC70-L-HWH-S, 2 pcs, with built in smoke bypass*

  • Equipment for control and monitoring

  • Technical documentation

  • Technical assistance, where required

* Smoke bypass valve prevents smoke from spreading where systems are designed to shut down automatically in case of fire.

As well as high indoor air quality, Topvex AHUs offer good energy efficiency. This is thanks to heat exchangers with low pressure drop and high heat recovery, and EC fans with high efficiency and low SFP values.

Check out our journey throughout the project

Pictures speaks louder than words

Topvex FSU
Topvex FSU
Wide range of compact floor standing units (FSU) with complete control system.
Wide range of compact and standardised air handling units for easy installation and fast delivery.
Topvex FCU
Topvex FSU