Heat Interface Unit for Underfloor Heating

The Baypayo Thera TKY Heat Interface Unit (HIU) for Underfloor Heating is an advanced apartment heating and domestic hot water solution designed for residential buildings supplied by central heating, district heating and communal energy systems.

Installed at apartment level, the Thera TKY HIU combines underfloor heating control, domestic hot water production, circulation, temperature control, heat metering, flow management and smart automation within one integrated system. Instead of treating heating, hot water and room temperature control as separate systems, Baypayo brings these functions together in a professionally engineered apartment-level heating solution.

Modern residential projects demand more than simply heating an apartment. Residents expect stable domestic hot water, comfortable floor temperatures, individual room temperature control, efficient hydraulic performance and the ability to manage their heating according to their daily lifestyle.

The Baypayo Thera TKY Heat Interface Unit has been developed to meet these requirements by connecting the apartment to a central heating system while allowing the heating and domestic hot water functions to be controlled according to the requirements of each dwelling.

For modern apartment buildings, residential developments and multi-family housing projects, the Baypayo Thera TKY combines the advantages of central heating with individual apartment comfort and control.

Domestic Hot Water Comfort with the Baypayo Heat Interface Unit

Domestic hot water is one of the most important elements of residential comfort. A heating system may provide excellent space heating, but if hot water temperature or flow is insufficient, the overall comfort of the apartment is immediately affected.

The Baypayo Thera TKY Heat Interface Unit is designed to provide instantaneous domestic hot water using heat transferred from the central heating system.

Depending on the selected configuration and project requirements, the system can be designed with 35 kW, 50 kW and 65 kW heat exchanger capacities.

Domestic hot water flow capacity can reach 21 litres per minute and higher flow rates depending on system design and operating conditions.

High domestic hot water comfort for bathrooms and kitchens

A modern apartment may require hot water simultaneously or at different times for showers, washbasins and kitchen use.

The Baypayo HIU transfers heat from the central heating circuit through a high-performance stainless steel heat exchanger to provide domestic hot water when required.

This approach allows the apartment to benefit from a central energy source while domestic hot water is produced at apartment level.

35 kW, 50 kW and 65 kW heat exchanger options

Not every apartment has the same hot water demand.

Apartment size, number of bathrooms, occupancy, water demand and project design all influence the required capacity.

The Baypayo Thera TKY range can therefore be configured with 35 kW, 50 kW or 65 kW heat exchanger capacity options, allowing the HIU to be selected according to the requirements of the residential development.

Why Heating Temperature Matters in Underfloor Heating Systems

Underfloor heating works differently from conventional radiator systems. Instead of concentrating heat around a relatively small radiator surface, heat is distributed through pipe circuits installed beneath the floor.

This creates a large radiant surface and can provide a more even heat distribution throughout the living space.

However, good underfloor heating performance depends on more than simply supplying hot water.

Flow temperature, return temperature, water flow rate, hydraulic balancing, room temperature and floor temperature all influence the performance and comfort of an underfloor heating system.

This becomes particularly important in multi-apartment buildings connected to a central heating system.

Different apartments do not necessarily have the same heating requirements.

A south-facing apartment receiving significant solar gain may require less heating than a north-facing apartment. Similarly, a corner apartment, an intermediate apartment and a top-floor apartment can have different heat-loss characteristics.

The ability to control heating at apartment level therefore becomes an important part of modern residential comfort.

Underfloor Heating Temperature Control with the Baypayo Heat Interface Unit

The Baypayo Thera TKY Heat Interface Unit is designed to provide individual apartment control for underfloor heating systems.

Depending on the system configuration, the underfloor heating supply temperature can be controlled within a 25–45°C range.

This temperature range is particularly relevant to underfloor heating, where lower flow temperatures are normally used compared with conventional radiator systems.

Individual heating comfort for every apartment

Central heating provides an efficient common energy source, but every resident may have different comfort requirements.

With an apartment-level HIU, each dwelling can manage its own heating conditions without requiring the entire building to operate at the same comfort setting.

One apartment may require a higher heating level while another may require less heat.

This creates a more flexible heating environment for multi-family residential buildings.

Balanced floor temperature

The purpose of underfloor heating is not simply to make the floor hot.

The objective is to provide stable and comfortable heat distribution throughout the living area.

Correct flow temperature combined with correct flow control and room temperature regulation helps the system operate in a controlled manner.

The Baypayo Thera TKY combines the HIU, circulation pump, manifold, actuators and room thermostats to create an integrated underfloor heating control system.

Underfloor Heating Flow Control with the Baypayo Heat Interface Unit

Water temperature is only one part of an underfloor heating system.

Water flow rate is equally important.

Every apartment has a different heating demand, and every underfloor heating circuit may require a different flow rate.

The required flow depends on factors such as:

• Floor area
• Pipe length
• Pipe diameter
• Circuit design
• Heat loss
• Room usage
• Building orientation
• Insulation level
• Required room temperature

The Baypayo Thera TKY HIU incorporates a dedicated circulation pump for the apartment's underfloor heating circuit.

This allows the secondary heating circuit to circulate water according to the heating demand of the dwelling.

Variable-speed circulation pump

The Baypayo Thera TKY configuration can incorporate a Grundfos-Baypayo AUTO UPM3 variable-speed circulation pump.

The specified pump configuration includes:

• Up to 7 m water head
• Up to 3.6 m³/h flow capacity
• Higher-capacity pump options for project-specific requirements

A variable-speed circulation pump helps regulate water circulation within the secondary underfloor heating circuit.

This is particularly useful in systems where the heating demand changes according to room temperature and actuator operation.

Room-by-Room Flow Control in Underfloor Heating Systems

A residential apartment does not have one single heating requirement.

A large living room may require more heating flow than a small bedroom. A bathroom may have a different heating demand from a hallway. A room with an external wall may require more heat than an internal room.

For this reason, professional underfloor heating systems require proper hydraulic balancing and individual circuit flow control.

Baypayo Flow-Controlled Underfloor Heating Manifold

The Baypayo Thera TKY HIU can be configured with a flow-controlled and actuator-equipped underfloor heating manifold.

Each individual UFH circuit can be adjusted according to its design flow requirement.

This allows different rooms to receive the appropriate amount of heating water rather than simply distributing the same flow to every circuit.

Why pipe length affects flow requirements

Underfloor heating circuits can have different pipe lengths.

Longer circuits generally create different hydraulic resistance compared with shorter circuits. If every circuit receives identical flow regardless of its design, the system may not achieve optimum hydraulic balance.

A properly designed flow-balancing manifold allows each circuit to be adjusted according to the requirements of the installation.

This is particularly important for achieving stable floor temperatures and consistent room comfort.

Room Temperature Control with the Baypayo Heat Interface Unit

A modern underfloor heating system should respond to the actual temperature of each room.

The Baypayo Thera series room thermostats are designed to work with the underfloor heating system and provide individual room temperature control.

Instead of heating the entire apartment continuously, the system can respond to the requirements of individual rooms.

Individual temperature control for every room

The living room, bedroom, children's room, kitchen and bathroom do not necessarily need to operate at the same temperature.

With Baypayo Thera room thermostats, each room can be assigned its own temperature setting.

When the desired room temperature is reached, the corresponding actuator on the underfloor heating manifold can be controlled to regulate the flow through the relevant UFH circuit.

This helps combine comfort and controlled energy consumption.

Wired and wireless room thermostats

The Baypayo Thera series is available with wired and wireless room thermostat options.

Depending on the project configuration, room temperature control can be integrated with the manifold actuators and central control panel.

Smart scheduling and mobile control

For compatible configurations, the Baypayo Thera system can support mobile-based programming.

Users can define heating schedules according to day and time.

For example:

• Higher temperature during evening hours
• Reduced heating during working hours
• Different temperatures during the night
• Separate schedules for weekdays and weekends

This provides a more personalized heating experience while helping avoid unnecessary heating when rooms are not in use.

Automatic Underfloor Heating Control Panel

Individual room thermostats provide local control, but a complete underfloor heating system also needs coordinated system-level control.

The Baypayo Thera TKY system can be configured with an automatic control panel that coordinates the room thermostats, manifold actuators and circulation pump.

When all heating zones have reached their target temperature and there is no heating demand, the control system can stop the circulation pump.

Pump control according to heating demand

Continuous circulation is not always required when there is no active heating demand.

By coordinating room thermostats, actuators and the circulation pump, the control system can operate the pump according to the actual demand of the apartment.

This approach supports both comfort and energy-conscious operation.

Heat Meter Integration with the Baypayo Heat Interface Unit

Heat metering is an important component of modern central and district heating systems.

The Baypayo Thera TKY HIU can be configured with Baypayo US1, US2 or R-series heat meters, depending on project requirements.

A heat meter measures the thermal energy delivered to an individual apartment.

Apartment-level heat measurement

Apartment-level heat metering allows the energy delivered to each dwelling to be monitored separately.

Measured data can support:

• Energy monitoring
• Consumption analysis
• Heat billing
• Heat cost allocation
• Building energy management
• Remote meter reading

This makes the HIU more than a heating device. It becomes part of the building's wider energy management infrastructure.

Remote Meter Reading and Energy Management

Modern residential heating systems increasingly rely on digital energy management.

The Baypayo Thera TKY system can be integrated with remote meter reading and control software, depending on project requirements.

This enables authorized users or service teams to manage meter data remotely and supports digital energy management applications.

Baypayo's approach combines:

Heat Interface Unit + Heat Meter + Automation + Remote Meter Reading + Software Integration

within an integrated residential energy management solution.

Baypayo OKV Online Prepaid Energy System

For projects requiring prepaid energy management, the Baypayo Thera TKY HIU can be configured with an OKV online prepaid system kit.

This solution can be considered for developments where energy usage is managed through an online prepaid or credit-based system.

Depending on the project architecture, the prepaid system can be integrated with the meter and remote control infrastructure.

This provides another option for digital energy management in multi-apartment developments.

Baypayo Thera TKY Heat Interface Unit Components

One of the major advantages of the Baypayo Thera TKY platform is its ability to combine multiple heating and control components into one project-specific HIU solution.

AISI 316 CrNi stainless steel heat exchanger

The Baypayo Thera TKY can incorporate an AISI 316 CrNi stainless steel plate heat exchanger.

Available capacity options include:

• 35 kW
• 50 kW
• 65 kW

The specified pressure rating is PN16 / 16 bar.

The stainless steel heat exchanger provides the heat transfer interface between the central heating system and the apartment's relevant heating or domestic hot water circuit.

AISI 316 stainless steel pipework

The HIU can use 18 mm AISI 316 CrNi stainless steel pipework.

The use of stainless steel pipework is part of the Baypayo engineering approach for the internal hydraulic assembly.

Balancing valves and flow control

Baypayo balancing valves can be incorporated for hydraulic control.

Flow limitation and pressure stabilization help maintain controlled hydraulic operation between the central heating network and the apartment heating circuit.

Check valves, fittings and valves

The system can include PN16 brass fittings, check valves and specially designed valve components according to the project configuration.

These components support controlled hydraulic operation and system reliability.

Temperature and pressure monitoring

Project-specific configurations can include thermometers and pressure gauges for monitoring the operating conditions of the HIU.

This makes it easier for installation and service personnel to check the system during commissioning and maintenance.

Baypayo Thera TKY Installation and Cabinet Options

Every residential development has different architectural and mechanical service requirements.

For this reason, the physical design of the HIU can be adapted to the installation conditions.

Concealed or flush-mounted Heat Interface Unit

For modern apartment developments, equipment is often required to occupy as little visible space as possible.

The Baypayo Thera TKY can therefore be configured for concealed, flush-mounted installation inside a wall or service cabinet.

Wall-mounted cabinet design

Where concealed installation is not suitable, a wall-mounted cabinet with cover can be used.

This provides accessible installation while keeping the technical components organized and protected.

Top or bottom pipe connections

Depending on the building services layout, the HIU can be designed with top-entry or bottom-entry pipe connections.

Project-specific connection arrangements can simplify integration with the building's central heating and domestic water pipework.

PX Flex Polyurethane Insulation

Thermal insulation is another important element of an efficient HIU.

The Baypayo Thera TKY system can incorporate PX Flex polyurethane insulation to help reduce unwanted heat loss from hot components and pipework.

Proper insulation contributes to maintaining the intended thermal performance of the unit while reducing unnecessary heat transfer to the surrounding installation space.

Why Choose a Heat Interface Unit for Underfloor Heating?

An underfloor heating system is not defined by a single component.

Its performance depends on the interaction between:

• Heat Interface Unit
• Heat exchanger
• Circulation pump
• Underfloor heating manifold
• Flow balancing
• Actuators
• Room thermostats
• Heat meter
• Automatic control panel
• Remote meter reading
• Building automation

The Baypayo Thera TKY brings these functions together into one integrated apartment heating solution.

This approach can simplify system design, installation, commissioning, maintenance and service for residential developments.

Baypayo Heat Interface Unit for Apartment Heating

The Baypayo Thera TKY is designed specifically around the requirements of apartment-level heating and domestic hot water systems.

Instead of installing separate solutions for apartment heating, domestic hot water and room temperature control, the HIU provides a compact interface between the central energy network and the individual dwelling.

This concept is widely used internationally under terms such as:

• Heat Interface Unit
• HIU
• Apartment HIU
• Flat Station
• Heat Substation
• Apartment Heat Station
• Residential Heat Interface Unit
• District Heating Substation

The terminology varies between markets, but the fundamental concept remains the same: the apartment is connected to a central heating network through an individual heat interface unit.

For underfloor heating applications, the HIU must be correctly configured for the required flow temperature, flow rate, hydraulic resistance and room control strategy. International HIU manufacturers also offer dedicated configurations for underfloor heating.

Baypayo Heat Interface Unit Manufacturer and Integrated System Approach

The Baypayo Thera TKY solution can be configured with a range of Baypayo components including:

• Heat Interface Unit
• Heat Meter
• Underfloor Heating Manifold
• Flow-Controlled Manifold
• Actuators
• Room Thermostats
• Automation Controls
• Remote Meter Reading
• Online Prepaid Energy System

This integrated approach is particularly valuable for large residential developments.

Instead of managing completely separate product and service chains, the project can be planned around one coordinated technical solution.

For developers, contractors and mechanical installation companies, this can simplify project coordination and after-sales service.

Baypayo Underfloor Heating HIU Service Network

A Heat Interface Unit combines several mechanical, hydraulic and electronic components. Correct installation, commissioning and maintenance are therefore important for long-term system performance.

Baypayo provides an authorized service infrastructure for its underfloor heating and HIU solutions.

The service structure can support:

• Heat Interface Units
• Heat Meters
• Heat Exchangers
• Underfloor Heating Manifolds
• Actuators
• Room Thermostats
• Meter Reading Systems
• Automation
• Remote Control Systems

For large residential developments, the documented Baypayo project configuration includes a 5-year warranty option.

Baypayo Underfloor Heating HIU Installation and Project Support

A successful underfloor heating installation requires more than supplying equipment.

The design, installation, hydraulic balancing, electrical connections, commissioning and control configuration all need to work together.

Baypayo provides project-oriented support for Thera TKY HIU installations.

Engineering and project support

Baypayo's project engineering team can support the technical planning of the HIU according to the requirements of the building.

Coordination during construction

Authorized service teams can assist with coordination between:

• Mechanical contractors
• Plumbing installers
• Electrical contractors
• Wall and finishing teams

This coordination is particularly important in projects where the HIU, underfloor heating manifold, room thermostats and electrical controls need to be installed at different construction stages.

Sample apartment installation

For large residential developments, installing and commissioning a sample apartment before mass installation can help establish the correct installation standard.

Baypayo can provide sample apartment installation and technical training support through its authorized service network.

System commissioning

After installation, the Baypayo authorized service team can commission the system.

The HIU, circulation pump, manifold, actuators, thermostats and control components are checked as an integrated system.

Meter reading and billing support

Depending on the project configuration, Baypayo authorized service teams can also provide monthly meter reading and billing support.

Annual maintenance and service

Regular inspection and maintenance help identify potential problems before they affect system performance.

Baypayo can provide annual maintenance and service support for configured projects.

Where Can the Baypayo Thera TKY HIU Be Used?

The Baypayo Thera TKY Heat Interface Unit is particularly suitable for residential projects using central or district heating systems and underfloor heating.

Potential applications include:

• Apartment buildings
• Multi-family housing
• Residential developments
• High-rise residential projects
• Luxury apartment developments
• Gated residential communities
• Central heating projects
• District heating developments
• Projects requiring apartment-level heat metering
• Residential buildings requiring individual room temperature control

The final HIU configuration should be selected according to the building's heating load, domestic hot water demand, hydraulic design and installation requirements.

A New Definition of Comfort with the Baypayo Thera TKY

Traditional central heating systems provide a common energy source for the entire building.

Modern Heat Interface Unit technology takes the concept one step further by keeping the advantages of centralized energy generation while giving each apartment a higher level of individual control.

With the Baypayo Thera TKY system, the apartment can control:

Underfloor heating temperature.

Room temperature.

Heating flow.

Domestic hot water.

Heat consumption.

Heating schedules.

Room-by-room comfort.

Automation.

Metering and remote energy management.

This is the difference between simply heating a building and creating a modern, individually controlled residential heating environment.

Baypayo Thera TKY – An Integrated Heat Interface Unit for Underfloor Heating

The Baypayo Thera TKY Heat Interface Unit for Underfloor Heating combines the key functions required for modern apartment heating systems.

With 35 kW, 50 kW and 65 kW heat exchanger options, AISI 316 CrNi stainless steel heat exchanger and pipework, variable-speed circulation pump, heat meter integration, flow-controlled underfloor heating manifold, actuators, wired or wireless room thermostats, automatic control, remote meter reading and project-specific automation, the system can be configured for different residential developments.

The combination of engineering, manufacturing, project support, commissioning and authorized service provides a complete approach for developers, contractors and mechanical installation companies.

For residential projects where underfloor heating, domestic hot water, heat metering, room temperature control and automation need to operate as one coordinated system, the Baypayo Thera TKY provides a comprehensive Heat Interface Unit solution.

Baypayo Thera TKY Key Features

• Heat Interface Unit for underfloor heating
• Apartment-level heating interface
• Central and district heating compatible configuration
• Domestic hot water production
• 35 kW, 50 kW and 65 kW heat exchanger options
• AISI 316 CrNi stainless steel heat exchanger
• PN16 / 16 bar pressure rating
• AISI 316 CrNi stainless steel internal pipework
• Grundfos-Baypayo AUTO UPM3 variable-speed circulation pump
• Up to 7 m water head
• Up to 3.6 m³/h pump capacity
• Project-specific higher-capacity pump options
• Hydraulic balancing and flow control
• Baypayo US1, US2 and R-series heat meter options
• Remote heat meter reading
• Remote monitoring and control
• Online prepaid energy system option
• Flow-controlled underfloor heating manifold
• Actuator-equipped manifold option
• Wired and wireless Thera room thermostats
• Individual room temperature control
• Heating schedule programming
• Automatic pump control
• Building automation integration
• Concealed / flush-mounted installation option
• Wall-mounted cabinet option
• Top or bottom pipe connection options
• PX Flex polyurethane insulation
• Project-specific engineering and configuration
• 5-year warranty option for collective residential projects
• Baypayo authorized service and project support