Windis Free 350
Surface-mounted air curtain
The water-heated Windis Free 350 is mounted on the surface above the doorway, which suits retail premises, offices, schools and daycare centres. Installation height up to 3.5 metres. Available in five widths: 1 m, 1.5 m, 2 m, 2.5 m and 3 m.
An integrated controller is included as standard and connects to the building management system. Also available in stainless steel.
Features
Energy metering, the heating valve and heating-network pressure measurement apply to water-heated models.
Performance
- Integrated thermal energy metering
- Adjustable discharge impulse
- EC fans
Installation
- Quick connectors for external sensors
- Integrated heating valve
Connectivity and monitoring
- Modbus TCP and BACnet IP interface
- Heating network pressure measurement
- Built-in frost risk detection
Construction
- Colours: body RAL 7035, grille RAL 7024, other RAL colours available to order
- Fan: EC centrifugal fans, ball bearings
- Heating coil: copper tubes 3/8", aluminium fins, max 6 bar @ 100 °C
- Electrical connections: power supply cable 2 m, earthed plug
- Other connections: M12 connectors, Ethernet, USB
Scope of delivery
Integrated inside the unit:
- Energy metering (ultrasonic flow measurement)
- 2-way heating valve, Belimo C215Q-J / C220Q-K
- actuator with 15 s running time
- discharge impulse control
- water in/out temperature measurement
- air in/out temperature measurement
- freeze risk detection
- heating network pressure measurement
- air bubble detection
- G4 filter
Interfaces: Modbus TCP, BACnet IP, Modbus RTU/BACnet MSTP, I/O.
Optional: filter differential-pressure measurement.
Technical data
Models: Free 350-100 · Free 350-150 · Free 350-200 · Free 350-250 · Free 350-300
Performance ranges, water heating
Scroll the table sideways
| Water temperature | Heating capacity (kW) | Water flow (l/s) | Pressure drop (kPa) |
|---|---|---|---|
| 70/40 °C | 10,3 – 36,7 | 0,082 – 0,293 | 3,0 – 6,5 |
| 60/30 °C | 5,8 – 21,7 | 0,047 – 0,173 | 1,7 – 3,8 |
| 50/30 °C | 5,4 – 19,5 | 0,064 – 0,233 | 2,4 – 5,1 |
Discharge air temperature 20 °C. The ranges cover all five widths (1 m – 3 m) and the fan control range 20–100 %.
The pressure drop applies to the heat exchanger. The site-specific operating point and pressure drop come from Select.
Exact site-specific sizing is done in Windis Select. The values shown are control ranges per series.
Airflow, sound pressure and fan
Scroll the table sideways
| Airflow (m³/h) | Sound pressure level (dBA) | Fan input power (W) |
|---|---|---|
| 222 – 4 868 | 33,0 – 79,1 | 8 – 692 |
The ranges cover all five widths (1 m – 3 m) and the full fan control range 20–100 %.
Sound pressure level LpA, Sabine 10 m². Alternative reporting 5 m / 200 m² (≈ –8 dB) for Free/Ceil 350 models in Select.
Dimensions and weights
Scroll the table sideways
| Model | Width (mm) | Height (mm) | Depth (mm) | Weight (kg) | Mounting |
|---|---|---|---|---|---|
| Free 350-100 | 980 | 250 | 550 | 46 | 4 × M8 |
| Free 350-150 | 1 480 | 250 | 550 | 60 | 4 × M8 |
| Free 350-200 | 1 980 | 250 | 550 | 79 | 8 × M8 |
| Free 350-250 | 2 480 | 250 | 550 | 95 | 8 × M8 |
| Free 350-300 | 2 980 | 250 | 550 | 111 | 8 × M8 |
Detailed dimension drawings per model are available in Windis Select.
Downloads
- Technical brochure
PDF · 0.9 MB · 4/2026
- Dimension drawings
PDF · 1.1 MB · 4/2026
- Installation instructions
PDF · 0.8 MB · 4/2026
- Functional diagram
PDF · 49 kB · 3/2026
- Modbus registers
XLSX · 33 kB · 3/2026
- Declaration of conformity
PDF · 0.1 MB · 4/2026
Size your project in Windis Select
Enter the door dimensions, the conditions and the heating type, and Select calculates the performance values and produces the documents for the design. Help with choosing the size class is available directly from Windis.