O.ERRE GHOST-U 100 ACTIVE local recuperator Ø100 mm – 30 m³/h
O.ERRE GHOST-U 100 ACTIVE is a compact local heat recovery ventilation unit, or recuperator , which allows you to improve the air exchange in a room without building a central ventilation duct.
The device is installed through an external wall in an opening of only Ø100 mm , which makes the GHOST-U 100 ACTIVE particularly suitable for apartments, private houses and buildings undergoing renovation, where it is difficult to make a ventilation opening with a larger diameter.
The maximum air flow is 30 m³/h . The ACTIVE version allows multiple GHOST-U units to be wired and synchronized to form a complete local ventilation system.
Why choose GHOST-U 100 ACTIVE?
One of the major advantages of the GHOST-U 100 ACTIVE is its small Ø100 mm installation opening. This makes the unit suitable for locations where installing a standard Ø160 mm local heat recovery unit is not possible or advisable.
This device is suitable for, for example:
- bedroom;
- the living room;
- the study and home office;
- an apartment;
- a single-family home;
- a building undergoing renovation;
- a room without proper ventilation;
- rooms with humidity and CO₂ problems.
According to the manufacturer, GHOST-U is designed for use in various living spaces, and multiple units can be synchronized to create a comprehensive ventilation solution.
Local ventilation with heat recovery
GHOST-U operates with an alternating airflow. The purpose of the device is to remove contaminated air from the room and replace it with fresh outdoor air, using the thermal energy of the exhaust air to improve the temperature of the incoming air.
This helps reduce the heat loss associated with conventional ventilation.
A local heat recovery unit is therefore a good solution in situations where continuous, controlled air exchange is desired without installing a ventilation duct system throughout the entire building.
Only a Ø100 mm opening
The GHOST-U 100 ACTIVE requires a 100 mm diameter opening for installation.
This is a significant advantage during renovation. A smaller opening generally means an easier installation through the exterior wall and allows for the use of local heat-recovery ventilation even in places where larger units do not fit well.
Airflow up to 30 m³/h
The GHOST-U 100 ACTIVE has a maximum airflow of 30 m³/h for both supply and exhaust.
Therefore, the Ø100 model is particularly suitable for local ventilation in small and medium-sized rooms.
If you need a higher air exchange rate, consider the GHOST-U 160 model, which has a maximum airflow of 60 m³/h.
ACTIVE – multiple devices working together
The GHOST-U 100 ACTIVE is primarily intended for use in a system.
Devices in the ACTIVE version are connected to each other via a cable and can be used in a master/slave configuration. Up to 16 devices can be connected to the system.
This allows, for example, one device to be installed in the bedroom and another in the living room, with the devices operating in a coordinated manner.
This is a key difference compared to the GHOST-U BASE version.
Integrated humidity and twilight sensors
The ACTIVE version includes humidity and twilight sensors, which enable the use of automatic operating modes.
The humidity sensor helps the ventilation system respond to changing conditions in the room, and the twilight sensor can be used to control quieter nighttime operation.
The unit has four adjustable ventilation speeds, including a special night mode.
Energy-efficient DC motor
The GHOST-U uses a brushless, electronically commutated DC motor designed for low energy consumption and a long service life.
This is important because ventilation systems typically operate for a large part of the day or around the clock.
Low noise level
The GHOST-U 100 ACTIVE is also designed for use in living and sleeping areas.
On the manufacturer’s current English-language website, the maximum noise level for the GHOST-U 100 ACTIVE is listed as 27 dB(A) at a distance of 3 meters.
For example,the Blauberg Inhome mini 100mm is the quietest unit at 23 dB(A) at a distance of 3 meters.
The Blauberg device also has built-in API capabilities (control via remote control, the device itself, and the app)
Note: There is a discrepancy here between different versions of O.ERRE’s documentation. The 2026 technical PDF lists 29 dB(A) and 6.9 W, while the manufacturer’s current English-language website lists 27 dB(A) and 4.2 W. Therefore, for the power consumption and noise level on the Pro Air product page, I would refer to the documentation for the specific version supplied to Estonia.
Easy to Maintain
The GHOST-U uses easily accessible, washable dust filters. The unit also features an LED indicator to show the device’s functions and when the filter needs maintenance.
This makes regular maintenance easier for the user.
No condensate drain is required
According to the manufacturer, the GHOST-U system does not require a separate condensate drain. The device’s operating temperature range is –30 to +50 °C.
This is a significant advantage when installing local ventilation, as there is no need to install separate condensate piping to the exterior wall.
Technical Specifications
| Feature | GHOST-U 100 ACTIVE |
|---|---|
| Manufacturer | O.ERRE |
| Model | GHOST-U 100 ACTIVE |
| Product Code | 0028610 |
| Equipment Type | Local ventilation with heat recovery |
| Installation opening | Ø100 mm |
| Maximum airflow | 30 m³/h |
| Supply Voltage | 220–240 V |
| Frequency | 50 Hz |
| Maximum pressure | 72 Pa |
| Protection Class | IPX4 |
| Weight | 3.5 kg |
| Operating temperature | –30…+50 °C |
| Connection to Other Devices | wired |
| Humidity Sensor | Yes |
| Twilight Sensor | Yes |
| Synchronizing Devices | Yes |
| Maximum number of devices in the system | up to 16 |
| Condensate Drain | is not necessary |
The key data is taken from O.ERRE’s official GHOST-U documentation.
GHOST-U 100 or GHOST-U 160?
The main differences are the installation opening and the airflow.
GHOST-U 100: Ø100 mm and up to 30 m³/h.
GHOST-U 160: Ø160 mm and up to 60 m³/h.
If the wall construction allows for a Ø160 mm opening and the room requires greater air exchange, the GHOST-U 160 model is the preferred choice.
However, if minimizing the wall opening is a priority, the GHOST-U 100 is a very attractive solution.
GHOST-U ACTIVE, WIRELESS, or APP?
The GHOST-U series is available in four versions:
ACTIVE – wired connection between devices.
WIRELESS – wireless connection between devices.
APP O.TECH – a Wi-Fi and app-based solution.
The GHOST-U 100 ACTIVE is a good choice when it is possible to install the necessary wiring between the units during the planning phase of the ventilation system.
Well-suited for renovations
GHOST-U 100 ACTIVE is particularly appealing for the renovation of existing apartments and single-family homes.
Installing a central heat recovery ventilation system may require running ventilation ducts throughout the entire building. With a local system, the units are installed directly on the exterior wall.
This makes it possible, for example, to improve ventilation in just a bedroom, living room, or home office without having to renovate the entire house.
Frequently Asked Questions
How large does the opening need to be to install the GHOST-U 100?
The GHOST-U 100 requires a Ø104 mm mounting hole.
How strong is the airflow of the GHOST-U 100 ACTIVE?
The maximum airflow is 30 m³/h.
Is the GHOST-U 100 suitable for a bedroom?
Yes. According to the manufacturer, GHOST-U is designed, among other things, for ventilating bedrooms and living spaces. In bedrooms with low airflow requirements, the Ø100 model is particularly appealing due to its small installation opening.
The quieter version is: The Blauberg Inhome mini 100mm is the quietest unit at 23 dB(A) at a distance of 3 meters
The Blauberg device also comes with built-in API capabilities (control via remote control, the device itself, and the app)
Can GHOST-U 100 ACTIVE devices be connected to each other?
Yes. ACTIVE-version devices are connected to each other via a cable, and up to 16 devices can be connected to a single system.
Does the device have a humidity sensor?
Yes. The ACTIVE version has built-in humidity and twilight sensors.
Does GHOST-U require a condensate drain?
No. According to the manufacturer’s documentation, a separate condensate drain is not required.
Is the GHOST-U 100 ACTIVE remote control included in the set?
This must be specified separately for each specific Pro Air kit. European distributors note that the control unit required to operate the ACTIVE version must be selected separately. The O.ERRE 2026 catalog also states that a control unit is required to use all the features of the ACTIVE version.
When should you choose the GHOST-U 160?
If a room needs more air exchange and a Ø160 mm wall opening is not a problem, the GHOST-U 160 has a maximum airflow of 60 m³/h, compared to 30 m³/h for the GHOST-U 100 model.
