Hybrid Radiant + FCU Control Solution for Heat Pump Homes

Overview

UFH and FCU systems often work against each other. Our unified control logic synchronises both - eliminating conflicts, simplifying installation, and delivering faster cooling when you need it.

Many heat pump projects combine underfloor heating (UFH) and fan coil units (FCUs) to balance winter comfort and summer cooling performance. However, traditional control approaches often rely on separate thermostats and independent control systems, creating operational conflicts and increasing installation complexity.

The Hybrid Radiant + FCU Control Solution integrates both terminal types under a single control platform. By coordinating heating, cooling, and automatic changeover logic, the system delivers room-by-room comfort while simplifying installation, commissioning, and day-to-day operation.See our detailed analysis on whether a single thermostat can effectively manage both FCU and underfloor heating →

Core Capabilities

● FCU + UFH control
● Changeover logic
● Heat pump ready
● Multi-terminal control
● Dew-point support

Dual-terminal control diagram for radiant floor heating and fan coil system

Solution Architecture

A unified thermostat platform coordinates radiant floors, fan coils, and heat pump operation through intelligent changeover logic. The system consists of the SAS922BFCH integrated thermostat, fan coil units, underfloor heating circuits, and a reversible air-to-water heat pump. The master controller coordinates seasonal mode selection and terminal prioritisation, while room thermostats manage individual zone temperatures.

Wired control system principle for heat pump with radiant floor heating and fan coil dual terminals

Feature	Pure Radiant System (UFH Only)	Hybrid Radiant + FCU System	Advanced Radiant Climate Control System
Terminal Type	UFH only	UFH + FCU	UFH + FCU + capillary
Heating	✓	✓	✓
Cooling Performance	comfort cooling	fast cooling	precision climate control
FCU Required	—	✓	✓
Capillary Required	—	—	✓
Multi-Zone Control	✓	✓	✓
Changeover Logic	standard	intelligent	advanced
Dew-Point Algorithm	—	✓	✓
System Complexity	low	medium	high
Installation Cost	lower	higher	highest
Recommended Project Type	standard residential	premium residential	luxury & high-performance homes

Architecture Highlights

One Thermostat Instead of Two
A single control platform — the SAS922BFCH — manages both fan coil units and radiant floor systems, eliminating duplicate wall controllers.

Intelligent Changeover Logic
Coordinates heating and cooling operation across multiple terminal types without user intervention.

Unified User Experience
Occupants interact with one thermostat regardless of how many terminal systems operate behind the scenes.

Simplified Installation
Reduces control wiring complexity and minimizes commissioning challenges.

Explore our full range of WCH Series radiant thermostats for scalable residential projects →

Application Scenarios

Heat Pump Villas-Unified Comfort Control

Challenge: Separate FCU and UFH controls create confusion and inconsistent room comfort.

Our solution: SAS922BFCH coordinates both terminal systems through one interface, providing seamless operation across heating and cooling seasons. Read our case study on seasonal mode switching logic in new-build projects →

● One thermostat

● Auto changeover

● Room control

Hybrid radiant and fan coil system solution for villa applications

Mixed-Terminal Homes - Eliminate Control Conflicts

Challenge: Independent FCU and UFH thermostats often compete for control during seasonal transitions.

Our solution: Integrated changeover logic automatically synchronizes terminal operation and heat pump mode selection

● Logic control

● Heat pump link

● Auto switching

Hybrid radiant floor heating and fan coil installation in multi-terminal residential living room

Residential Retrofits - Add Cooling Without Complexity

Challenge: Many homes upgrading to heat pumps require cooling without introducing multiple control systems.

Our solution: The hybrid architecture combines existing radiant heating with new FCU cooling under one thermostat platform.

● Retrofit ready

● Wi-Fi control

● Hybrid system

Hybrid radiant floor heating and fan coil system in renovated older home living room

Need a Different Radiant Control Approach?

Whether you're looking for a simpler radiant-only system or a more advanced multi-terminal climate solution, explore our full range of radiant control architectures.

Explore Pure Radiant Heating & Cooling Solution Explore Advanced Radiant Climate Control Solution

Advantages

Built for homeowners and developers seeking faster cooling performance with radiant comfort.

One Thermostat for Multiple Systems

Manage fan coils and radiant floors through a single interface, improving usability and reducing wall clutter.
Faster Cooling Performance

Fan coil units provide rapid cooling response while radiant floors maintain long-term thermal comfort.
Optimized for Heat Pump Projects

Designed specifically for residential air-to-water heat pump applications where mixed terminal systems are increasingly common.

Related Products

SAS922BFCH FCU & UFH 2-in-1 Radiant Thermostat

LEARN MORE

Power supply voltage: 85~250VAC, 50/60Hz

Room temperature display range: 0°C~50°C

Room humidity display range: 5~95%

Dew point temperature measurement range: 0~50°C

External temperature measurement range: 0°C~60°C

Set temperature display range: Cooling 20°C~30°C, Heating 16°C~26°C

Room temperature display accuracy: 0.1°C

External temperature sensor type: NTC 10K

Storage and transportation environment: Temperature -20°C~70°C; Humidity 5~95%

Installation dimensions: 86*86mm

Product dimensions: 86x86x12mm

Protection class: IP21

FAQ

By combining radiant floors for base heating/cooling with FCUs for peak load response, the system optimizes heat pump operation. Radiant floors handle steady-state comfort at low water temperatures, while FCUs provide rapid temperature adjustment without overworking the heat pump.

Yes. The intelligent changeover logic automatically synchronizes FCU and UFH operation, preventing conflicts during sudden temperature swings. The system maintains consistent indoor comfort without hunting or overshooting.

● Temperate climates: Excellent year-round performance with minimal FCU usage.

● Warm climates: FCUs handle peak cooling loads while radiant floors maintain baseline comfort.

● Cold climates: Radiant floors provide stable heating; FCUs supplement when rapid warm-up is needed.

FCUs require periodic filter cleaning and inspection (typically annually), which adds a small maintenance overhead compared to pure radiant systems. However, the unified control platform simplifies overall system management.

Yes. Each zone can operate FCU, UFH, or both simultaneously depending on comfort demand. The changeover logic ensures coordinated operation without thermal conflicts between air and floor loops.

Get in Touch

Contact our friendly customer service team for any questions, concerns, or suggestions. We'd love to hear from you.

Headquarters Hotline: +86 755 61218391 Headquarters Hotline +86 755 61218391

Headquarters Email: info@saswell.com

Tech Support Email: support@saswell.com

Hybrid Radiant + FCU Control Solution for Heat Pump Homes

Overview

Solution Architecture

Application Scenarios

Advantages

Related Products

SAS922BFCH FCU & UFH 2-in-1 Radiant Thermostat

FAQ

How does the hybrid system improve energy efficiency?

Is the hybrid system stable during rapid outdoor temperature changes?

How does performance differ across climate zones?

Does the hybrid system require more maintenance than pure radiant?

Can the FCU run independently from the UFH?