Residential Underfloor Heating Control with Smart Room Thermostats

Multi-zone temperature control for a hydronic floor heating application

A residential apartment project required independent temperature control for the living area, bedrooms, bathroom, and other heating zones. The hydronic underfloor heating system provided the required heating capacity, but the room control needed to be organized so that each zone could respond to its own temperature demand.

CosyClimate supplied a room thermostat and actuator control approach for the underfloor heating manifold. Each thermostat controls the actuator assigned to its heating loop, allowing the rooms to operate independently rather than relying on one temperature setting for the whole apartment.

1. Project Summary

2. Project Overview

The apartment was divided into several heating zones. The living room, bedrooms, bathroom, and other spaces did not need to follow the same temperature setting or the same operating schedule.

For this type of installation, the control task is relatively simple but important: each room thermostat must sense the local temperature and call for heat only when that zone requires it. The corresponding actuator on the underfloor heating manifold then opens the loop and allows warm water to circulate through that zone.

The project therefore focused on the room-control layer rather than changing the heat source or the hydraulic distribution system.

3. Customer Challenges

Independent control for each room

A single central thermostat would not reflect the temperature conditions or occupancy pattern of every room. The installer needed separate control for each heating zone.

Different operating schedules

Bedrooms, living areas, and bathrooms are used at different times. Keeping all zones at the same setpoint throughout the day would make the system less practical to operate.

Reliable actuator control

Each thermostat needed to provide a clear heating demand to the corresponding manifold actuator so that the correct loop opened and closed at the right time.

Simple day-to-day operation

The control interface had to remain straightforward for occupants. Common adjustments such as temperature setpoint and schedule changes should not require access to installer settings.

4. Heating Solution: Room Thermostat and Manifold Actuator Control

Each heating zone was equipped with an individual room thermostat connected to the thermal actuator serving that zone on the underfloor heating manifold.

Room Temperature Control

The thermostat continuously measures the room temperature and compares it with the user setpoint. When the room requires heat, the thermostat sends a heating demand to the actuator. When the setpoint is reached, the heating demand stops and the actuator closes.

Zone-by-Zone Operation

Because each room has its own thermostat and actuator, the zones can operate independently. A bedroom can remain at a lower setpoint while the living area is maintained at a higher comfort temperature.

Scheduling

Weekly schedules can be used to match normal occupancy patterns. Setpoints can be reduced during periods when a room is normally unused and restored before the space is occupied again.

Control Options

The thermostat platform can be selected according to the project specification. Depending on the model and installation requirements, options can include conventional wired control or connected functions for remote adjustment. The control method should be selected according to the actual project rather than adding communication functions that are not required.

5. System Architecture

The basic control path for each heating zone is:

The boiler or heat pump supplies heated water to the manifold as part of the hydronic system. The room thermostats do not replace the heat source controls; their role is to manage demand at room and zone level.

Operating Sequence

1. The thermostat measures the temperature in its room.

2. When the measured temperature is below the setpoint, the thermostat calls for heat.

3. The corresponding manifold actuator opens the heating loop.

4. Warm water circulates through the underfloor heating circuit for that zone.

5. When the room reaches the required temperature, the thermostat removes the heating demand and the actuator closes.

6. Installation and Commissioning

Check the heating zones

Confirm the number of rooms, manifold loops, actuator type, thermostat locations, and available wiring before selecting the control configuration.

Match thermostats and actuators

Verify operating voltage, output type, actuator compatibility, and the required control logic.

Install and wire the controls

Mount the room thermostats in suitable locations and connect each thermostat to the actuator assigned to its heating zone.

Configure room settings

Set temperature limits, schedules, and relevant installer parameters according to the project requirements.

Commission each zone

Test thermostat temperature response, actuator opening and closing, zone identification, and heating operation before handover.

7. Project Results

After commissioning, each room could be controlled according to its own setpoint and schedule. The control arrangement gave occupants a clearer way to manage comfort in individual spaces and gave the installer a repeatable zone-control structure for the apartment.

· Independent temperature control for the main heating zones

· Automatic opening and closing of each manifold loop according to room demand

· Different schedules and setpoints for rooms with different usage patterns

· Straightforward adjustment for occupants

· A control structure that can be applied to other apartment layouts with similar hydronic underfloor heating systems

No specific energy-saving percentage is claimed for this application because actual consumption depends on the building envelope, heat source, weather, occupancy, setpoints, and operating schedule. The practical benefit of the control upgrade is that heating demand can be managed by room instead of operating all zones in the same way.

8. Key Benefits of the Solution

Need a Heating Control Solution for Your Residential Project?

CosyClimate supports HVAC distributors, installers, system integrators, and OEM partners with thermostat solutions for residential heating applications.

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