Flexit Nordic S4 is the most powerful central air handling unit in the Norwegian Nordic series — engineered for large family homes, multi-storey apartments and commercial spaces. The rotary heat exchanger delivers a thermal efficiency of up to 85 %, airflow up to 461 m³/h and a built-in humidity sensor with full control via the Flexit GO app. The Ø160 mm duct connection enables coverage of extensive ductwork systems. Available in right-hand (RER) and left-hand (REL) configurations. The ideal solution for demanding projects where high ventilation capacity and maximum energy savings are essential.
Key Benefits
Smart Control with Flexit GO
Control the unit from anywhere via the mobile app or web interface. Modbus support for smart home integration. Optional CI70 control panel for local operation.
Flexible Installation with Ø160 mm Ducts
Mount the unit on a wall, stand it upright or lay it horizontally on the floor. The Ø160 mm duct connection reduces pressure losses in extensive ductwork systems. Available in left-hand and right-hand configurations.
Kitchen Hood Connection
Simple connection to a kitchen hood via the bypass duct (Ø125 mm). Supports effective extraction of cooking fumes directly through the central ventilation system.
Healthier Air Throughout the Home
Dual F7 filtration captures dust particles, pollen and allergens. Heat recovery removes excess humidity and CO₂, reducing the risk of mould growth and allergic reactions.
Why a rotary heat exchanger?
Unlike plate heat exchangers, a rotary heat exchanger provides higher heat recovery efficiency in cold climates. Seasonal heat recovery (summer and winter) is a standard feature of the Nordic range — the unit rejects heat from the supply air in summer and recovers it in winter.
For sub-zero operation, a defrost function is available in the Flexit GO app, preventing ice build-up and ensuring reliable year-round performance.
Annual Energy Savings
Flexit Nordic S4 significantly reduces heating costs thanks to the high-efficiency rotary exchanger and higher airflow capacity. Estimated annual savings by climate zone:
(e.g. Scandinavia, mountain regions)
(e.g. Central Europe)
(e.g. Mediterranean region)
Technical Specifications
| Parameter | Value |
|---|---|
| Temperature efficiency | up to 85 % |
| Max. airflow | 461 m³/h at 100 Pa |
| Heat exchanger type | Rotary (enthalpy) |
| Filter class | 2× ePM1 55 % (F7) |
| Filter dimensions | 247×365×31 mm |
| Sound power level | 38 dB(A) |
| Rated voltage | 230 V / 50 Hz |
| Rated power (total) | 1,200 W |
| Fan power | 2×115 W |
| Electric heater power | 800 W |
| Rotor motor power | 4 W |
| Rated current | 7.0 A |
| Fuse | 10 A |
| Fan type | B-wheel, 0–10 V control |
| Duct connection | Ø160 mm |
| Kitchen hood connection | Ø125 mm |
| Dimensions (W×H×D) | 753×727×610 mm |
| Weight | 62 kg |
| Colour | White, RAL 9016 |
| IP rating | IP21 |
| Control | Flexit GO (LAN, cloud, app) |
| Compatibility | Modbus, Flexit GO, CI70 panel (optional) |
| Configuration | Right-hand (RER) / Left-hand (REL) |
Flexit Nordic S4 vs S3 vs S2 — which model to choose?
Nordic S4 is the most powerful model in the Nordic series with airflow up to 461 m³/h and Ø160 mm duct connection — ideal for large family homes and multi-storey buildings. All models share the same rotary exchanger with 85 % efficiency, Flexit GO control and F7 filtration.
For smaller apartments and homes, choose Flexit Nordic S2 (349 m³/h, Ø125 mm). For mid-size projects, consider Flexit Nordic S3 (361 m³/h, Ø125 mm).
Maximum performance. Quiet operation. Healthy air for the whole home.
Flexit Nordic S4 is the most powerful central air handling unit in the Nordic series for demanding projects requiring high airflow, maximum energy savings and intuitive smart control — available in right-hand (RER) and left-hand (REL) configurations.
| Model (Exterior side) | REL (Left) or RER (Right) |
| Brand | Flexit |
| Max. air flow m³/h | 475 m³/h |