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LK Group

  • LK Systems

    LK Systems is the leading manufacturer of easy-to-install systems for heating and tap water distribution and pre-insulated pipes in the Nordics. Through our prefabrication factory, we also provide tailor-made solutions that simplify the installation process even further. Svenska English Norsk Suomi

  • LK Armatur

    LK Armatur is a leading producer in Europe, manufactures millions of valves per year for the global HVAC market. Our solutions are based on a comprehensive view of how valves, control units, components and prefabricated products work together. Svenska English Deutsch Italiano Yкраїнська Suomi

  • LK Pex

    Our PEX Pipe Extrusion business area is an innovative manufacturer of high-quality plastic pipes for the heating and plumbing industry. Our core is the efficient, high-technology production process for crosslinked PE-Xa pipes, resulting in products with a unique combination of flexibility and hydrostatic strength. English

  • LK Group

    LK is a family-owned trading and production group, operating on a global scale within the HVAC-area. We are the market leader in Sweden and has an increasing sales of products, systems and solutions in the Nordic countries, Europe and the USA. Svenska English
Hydronic-underfloor-heating-multi-family-apartment-building

Underfloor heating in multi‑family buildings

Efficient heating solution for modern building projects

Underfloor heating is becoming a preferred choice in multi-family buildings. It offers comfort, energy efficiency, and flexible design. By distributing heat evenly across the floor surface, it creates a pleasant indoor climate without the cold spots often found with radiators.

Why underfloor heating works well in apartment buildings

  • Lower operating temperatures: Underfloor systems typically run with lower water temperatures than radiator systems, which improves efficiency, especially when paired with heat pumps or district heating.

  • More usable space: With no visible radiators, apartments gain cleaner wall layouts and more freedom for furnishing.

  • Quiet, even comfort: Heat rises gently from the floor, reducing draughts and temperature fluctuations.

  • Modern efficiency standards: It supports low-energy building concepts and can help meet strict regulations for new construction and renovations.

Benefits for planners and developers

  • Zoning and control: Individual room control and apartment-level metering can improve comfort and cost transparency.

  • Sound and insulation layers: Proper build-up reduces impact noise and prevents heat loss to lower floors.

  • Hydraulic balancing: Essential to ensure each apartment receives the correct flow and heat output.

  • Installation and long-term operation: A well-installed underfloor heating system is low-maintenance and durable. With quality components, correct commissioning, and clear documentation for facility management, it can provide stable performance for decades.

For modern multi-family projects, underfloor heating offers a strong balance of comfort, efficiency, and future-ready heating technology. Let us go through these positive aspects in more detail.
Girl-walking-barefoot-on-floor

Architectural freedom

Underfloor heating gives architects greater freedom in their design work. As the heating is concealed in the floor, there is no need for visible pipework on walls or radiators that interfere with the interior layout. Manifolds can be concealed behind hatches designed to blend in with the wall finish, making the apartment more attractive on the housing market. Residents are well aware that underfloor heating provides high comfort and a sense of everyday luxury.
Multi-family-building-construction-site

Support for property projects

As an HVAC consultant, you receive support throughout the process. LK has more than 40 years of experience in underfloor heating, and our team can support you from early system design documentation through to completed construction documents. We are happy to share our long experience to simplify the work and ensure a successful end result. To support correct installation, LK also offers project start-up meetings with the parties involved – everything to achieve the high quality the client can expect.

Water-borne underfloor heating for better economy and indoor comfort

Water-borne underfloor heating is common in single-family homes and is becoming increasingly common in multi-family buildings. In combination with a heat pump, the system can provide more heat per kWh used than radiator systems. Benefits include:

  • Suitable for all floor types and building constructions
  • Energy-efficient low-temperature underfloor heating system
  • More even and comfortable indoor heat than radiator systems
  • Increases apartment appeal and makes properties easier to sell or rent out
  • A better heating option for allergy sufferers
  • Good heating economy and improved energy performance
Underfloor-heating-apartment

Systems adapted for multi-family buildings

Building structures vary, from traditional cast-in-place concrete to timber constructions. We offer several different systems, each with properties suited to its application. Out of our total of 11 systems, we have selected the 6 most suitable for installation in multi-family buildings below. All systems are proven solutions and developed and adapted for the Nordic market.

 

Raised floor construction / service floor

When a raised floor construction is used, the underfloor heating can be integrated directly into the floor panel. With LK HeatFloor 22, the underfloor heating system does not add any build-up height. LK HeatFloor 22 meets the strict requirements of the Nordic Swan Ecolabel, and the construction has also been tested and verified by RISE.
LK-HeatFloor-22-timber-joists

LK HeatFloor 22 installed on timber joists

The standard chipboard flooring in the construction is replaced with the grooved chipboard panel LK HeatFloor 22.

After the grooved panel has been installed, heat distribution plates are fitted to ensure even heat distribution across the floor surface. The underfloor heating pipes are then laid in the grooves, and the installation is covered with the selected floor finish.

Granab

LK HeatFloor installed on Granab

LK HeatFloor 22 is also well suited for installation on Granab’s floor joist system. The Granab floor joist system is fixed to the structural floor.

The cavity created can be used for routing pipes and other building services. Granab’s floor joist system is type-approved by SP and has Norwegian technical approval from SINTEF for sound-insulating properties, dynamic load and strength. Granab’s floor joist system combined with LK HeatFloor 22 is an optimal solution and has been used in several of Sweden’s tallest buildings.

Semi-precast slabs / cast-in-place concrete / HDF floor slabs

For semi-precast slabs, cast-in-place floor slabs and HDF floor slabs, the underfloor heating pipes can be cast directly into the structural concrete. The advantage is that the underfloor heating system does not add any build-up height. Normally, the floor slab needs to be insulated to ensure a good indoor climate in all apartments in the building.
LK-Clip-Rail-Combi-16/20

LK Clip Rail Combi 16/20

Ideal for installation when casting underfloor heating pipes in concrete. The clip rail is fixed using a nail gun. The pipes are then laid easily according to the designed c/c spacing. Once the pipes are installed, the concrete is cast.

LK-System-Plate-30

LK System Plate 30

Suitable for so-called two-layer casting. The system plate acts as a pipe holder and also provides insulation to prevent heat loss to the floor below.

Systems for load-bearing floors

For load-bearing floors, LK offers board-based systems installed on top of the load-bearing structure. LK CombiBoard EPS is based on EPS S300 insulation board with a laminated heat distribution layer and is available in several thicknesses. LK Foil Board Silent is designed for dry areas and includes impact sound-reducing properties.

 
LK-CombiBoard-EPS

LK CombiBoard EPS 14/18/30/50/70

LK CombiBoard EPS is based on an EPS insulation board, class S300, with a laminated heat distribution layer for optimal heat spread. It is available in thicknesses of 14, 18, 30, 50 and 70 mm.

The system is suitable for many types of floor finishes. One major advantage is that ceramic floor finishes in dry areas can be installed directly on the boards.

LK CombiBoard EPS has high insulating performance and very good properties for both short-term and long-term loads. The EPS boards are supplied with pipe grooves and integrated return grooves.

LK-Foil-Board-Silent

LK Foil Board Silent

For underfloor heating in dry areas. A robust system based on a 30 mm or 50 mm EPS insulation board with impact sound-reducing properties.

The foil board is tested in accordance with EN ISO 140-8. The underfloor heating pipes are embedded in self-levelling compound, after which the selected floor finish is installed.

IsoMax meets increased energy requirements

LK Riser Manifold IsoMax is designed to optimise insulation on risers. The manifold is positioned separately from the risers, allowing pipe insulation up to class R4 to be installed on the risers in the standard version while maintaining full functionality, in accordance with current industry standards. Multi-family buildings with high energy requirements are becoming increasingly common, especially in projects aiming for environmental certification. Whether for new-build or renovation projects, IsoMax is an excellent choice!

LK-Riser-Manifold-IsoMax

Unique solution

LK IsoMax is a unique product developed specifically for multi-storey buildings. The design does not limit the thickness of the pipe insulation, as the riser is located outside the manifold cabinet.

Cost efficiency

LK IsoMax is energy-efficient because it enables continuous, maximum insulation. Efficient installation with few work steps thanks to a high degree of prefabrication.

Underfloor-heating-cooling-symbols

Underfloor heating combined with underfloor cooling

Multi-family buildings with underfloor heating cast into the floor slabs have a built-in “bonus function”. During spring, summer and autumn, the underfloor heating system can also be used as a distribution system for comfort cooling.

If the building’s heat source is a ground source heat pump, there are additional benefits. The boreholes can be used to produce so-called free cooling, where the operating cost for cooling is almost negligible. In operation, the main cost is the electricity used by the circulation pump.

When the building is cooled, the borehole is warmed up, which increases the efficiency of the ground source heat pump during the heating season. To enable free cooling, the control system must be supplemented with cooling equipment.

Read more about Underfloor Cooling

Blending In. Standing Out.

Heat should be felt, not seen. It should simply be there and work – like a warm welcome when the door opens to a home. Comfortable heating that provides an even room temperature.

Underfloor-heating-controll-app-mobile-phone

Individual room temperatur control

LK Arc room thermostats combine timeless, selectable design with connectivity and smart functions. LK Arc is an optimised room temperature control system that provides full control of comfort and function. The controller unit, sensors and thermostats communicate wirelessly, wired, or in a combination of both. The visible units have discreet, selectable designs, making it easy to integrate LK Arc into any interior environment.

 

Connected freedom

With the MyLK app, residents or property owners are always connected and have full control of the underfloor heating system via mobile phone or tablet. The temperature can easily be controlled room by room. The app includes several smart functions and is very easy to use. For example, users can activate the holiday function or control the heating in a summer house remotely with a simple tap.

Read more about Digital Services

Services and support

  • Calculations
    LK performs project-specific pressure-drop and flow calculations tailored to your underfloor heating installation.
  • Installation proposals
    LK prepares installation proposals as a basis for tender documentation or construction documents.
  • Consultation
    Your LK sales representative is always close at hand and happy to act as a sounding board. Contact us.
  • Project start-up meeting
    LK is happy to be on site at the start of the project to provide training and highlight key installation points – all to help ensure a successful final result.