SESERAGI® S400
Balanced heat-recovery ventilation without ducts. Wall-mounted units alternate between supply and exhaust. No ducts in the ceiling, no duct cleaning.
Patented JP Patent No. 5937811 10-year warranty on fan unit and heat-storage element※
How it works
SESERAGI® S400 units are installed in a sleeve through the outer wall and always work in pairs (one set = 2 units). While one unit supplies fresh air, the other extracts room air. Every 60 seconds they swap roles.
1. Exhaust phase
Warm room air passes a ceramic heat-storage element and leaves its heat there.
2. Supply phase
Incoming outdoor air passes the same element, takes up the stored heat and enters the room close to room temperature.
3. Pair operation
The two units of a set run in opposite directions, so supply and exhaust stay balanced (type 1 ventilation).
Why builders choose SESERAGI®
No duct design, installation or cleaning
Supply and exhaust happen at the wall. No ceiling space is needed for ducts.
Heat stays in the house
Heat exchange efficiency up to 95 %*1.
Low power, low noise
6.4 W for a home with 4 sets*2. Fan sound 9.2 dB(A) at airflow level 1.
Planning for every project
From the floor plans we prepare the ventilation calculation, the layout drawing and the quote. Used in more than 10,000 homes across Japan.
- *1 Third-party test by TÜV SÜD (Germany) to FprEN 13141-8:2021-07: 95.0 % at the minimum airflow of 13.3 m³/h and 5 °C outdoor temperature (85.3–88.5 % at the reference airflow of 48.7 m³/h).
- *2 The number of units depends on the building.
- ※Shipments from 1 November 2026, subject to the warranty terms (Japanese).
Components
Ventilation unit
Fan and ceramic heat-storage element in a wall sleeve. The indoor cover comes off for cleaning the fan unit and the filter.
Type SKH150se-S400 (KK2 or NWC, depending on the outdoor hood)
Outdoor hood
- KK2: stainless steel, silver or black (black with a paint surcharge)
- NWC: wind-resistant ABS hood
Controller
- VMPX-N4 / N8: up to 4 / 8 units
- VMPX-NH4 / NH8: with humidity sensor
- VMPX-AQ4 / AQ8: with CO₂ sensor – raises the airflow when the indoor CO₂ level rises
Fire damper (FD version)
For buildings that need a fire damper in the outer-wall opening. Types FD150s-72 °C / FD150s-120 °C. We check whether it is needed when we prepare the quote.
Specifications
| Type | Ductless balanced heat-recovery ventilation (alternating supply/exhaust, type 1) |
|---|---|
| Heat exchange efficiency | up to 95 %*1 |
| Power consumption | 1.6 W per set / 6.4 W for 4 sets*2 |
| Fan sound | 9.2 dB(A) at airflow level 1 |
| Switching interval | 60 s |
| Airflow | max. 80 m³/h per unit; 40 m³/h per unit in the ventilation calculation |
| Airflow levels | 4 |
| Units per controller | up to 8 |
| Wall sleeve | outer Ø 165 mm, 400 mm long |
| Heat-storage element | ceramic honeycomb, Ø 154 mm × 150 mm |
- *1 Third-party test by TÜV SÜD (Germany) to FprEN 13141-8:2021-07: 95.0 % at the minimum airflow of 13.3 m³/h and 5 °C outdoor temperature (85.3–88.5 % at the reference airflow of 48.7 m³/h).
- *2 The number of units depends on the building.
| Part | Type | Note |
|---|---|---|
| Unit + hood KK2 | SKH150se-S400KK2 | stainless, silver / black |
| Unit + hood NWC | SKH150se-S400NWC | ABS, wind-resistant |
| Controller | VMPX-N4 / N8 | up to 4 / 8 units |
| Controller (humidity) | VMPX-NH4 / NH8 | humidity sensor |
| Controller (CO₂) | VMPX-AQ4 / AQ8 | CO₂ sensor |
| Fire damper | FD150s-72 °C / 120 °C | FD version |
A cold-climate version is used in Hokkaido. Details, drawings and manuals (Japanese) are on the Japanese product page and in the downloads.
Maintenance
Check and clean the filter every 3 to 6 months, and the fan unit with the heat-storage element once a year – all from inside the room. The standard filter is washable; the fan unit with the element is washed in water below 40 °C. PM2.5/pollen filters are not washable and are replaced. Without ducts there is no duct cleaning.
Planning a project in Japan?
Send us the floor plans and we prepare the ventilation calculation, layout drawing and quote free of charge (documents in Japanese).