EHV - Humidity-controlled valves


EHV Valve for demand-controlled extract air from e.g. bathroom or utility room. The EHV valve is available in 3 variants with different override principles, see below.


The EHV extraction unit provides intelligent control of extract air according to need. The resulting system both provides optimum energy consumption and helps to create a better indoor climate.

EHV is especially suitable for bathrooms and environments that require increased airflow when there are high humidity levels in the room.

Product description
The EXHAUSTO EHV extraction unit has a patented humidity control, which uses forced airflow when humidity increases. The unit self-adjusts to normal airflow as humidity decreases. The patented humidity control mechanism is mechanically actuated and requires no power supply or battery. However, models with forced extraction, via an external signal or motion sensor, will require power supply, via a battery or transformer.

The unit is  permanently set to force air when relative humidity reaches 40%. The unit's damper is made of two parts. One half of the damper can be adjusted for six basic levels of airflow. The other half of the damper provides extra forced air. The total airflow is the sum of the basic and the forced airflow.



The EHV valve is available in 4 variants with different override principles. Get an overview of the variants below or read the detailed description beneath the table.

EHV versions EHV-B EHV-S EHV-P
Humidity-controlled forced extraction X X X
Forced extraction via external signal (switch not supplied by EXHAUSTO) X
Forced extraction via motion sensor  


Output signal when motion sensor is activated (digital)    
Battery supply 2x1.5 Volt AAA batteries (life approx. 2 years)* X  X 
Adjustable basic airflow X X
Material White ABS plastic RAL9003

* Option for replacing batteries with 12VAC power supply, EHV Supply Card

Generally, for all tree models:

All EHV valves consist of two damper plates, one permanently fixed for basic ventilation (can be set in positions 0 to 5) and one variable plate controlled by the relative humidity. The humidity-controlled damper plate will start to open at 40% RH and will be fully open at 85% RH.

Function description of the individual models:


Humidity-controlled extraction unit


Humidity-controlled air extraction unit overridden by an external ON/OFF switch. The two cables from the EHV are routed to a single-pole switch. When contact is made, the valve will open the humidity section to max. after approx. 1 min. When the contact is broken, the damper plate will close again after 20 minutes - unless the humidity is so high that this damper section remains partly open.


Humidity-controlled air extraction unit overridden by an integral PIR sensor. The PIR sensor must be activated via movement twice, with a maximum of one minute's interval, in order to make the contact. When contact is made in the PIR sensor, the valve will open the humidity section to max. When the contact is broken, the damper plate will close again after 20 minutes - unless the humidity is so high that this damper section remains partly open.

Dimensioned sketch



EHV målskitse



EHV - Capacity

Setting basic airflow

The fixed damper can be set to six different positions:

  • To change the required airflow
  • To adjust to the available pressure

The damper is set manually and locked using the supplied locking-pin in order to avoid the damper setting being changed by accident, e.g. during cleaning.


The damper is factory-set to position 0, which is min. airflow.

Moving the damper position down allows a higher airflow.
Each separate step increases airflow by approx10 m3/h (maximum = 50 m3/h)


EHV, airflow dependent on % RH at 30 Pa

EHV Capacity 30 Pa

 Adjustment options: (50 Pa)   Min Max 
 Basic airflow  m3/h (l/s)  6.5 (1.8) 23 (6.4)
 Humidity-sensitive section  m3/h (l/s)  31.7 (8.8) 42.8 (11.9)
 Forced airflow  m3/h (l/s)  38.2 (10.6) 65.9 (18.3)

EHV, airflow dependent on %RH at 100 Pa

EHV Capacity 100Pa

Adjustment options: (100 Pa)     Min  Max
Basic airflow m3/h (L/s)   12 (3.3)  42 (11.7)
Humidity-sensitive section m3/h (L/s)  68 (18.9)  88 (24.4)
Forced airflow m3/h (L/s)  80 (22.2)  130 (36.1)

Sound data

Sound data for EHV valve



EHV, internal silencing
Hz 63 125 250 500 1K 2K 4K 8K
dB 22 16 10 5 2 1 0 0



Mount the EHV valve to the wall or ceiling duct with a metal fire protection panel (FPP) which simultaneously protects the duct system in accordance with DS428 (Technical measures for fire protection of ventilation systems).


Panel includes spigot with rubber seal for airtight fitting in a Ø100 mm duct.


Panel includes spigot with rubber seal for airtight fitting in a Ø125 mm duct. 


Panel for fitting to another type of duct opening:
- Rectangular from 67 x 75 mm up to 75 x 67 mm
- Circular from Ø88 up to Ø100 

Initial adjustment

It is important to adjust the valve to match the required airflow.

Step What to do Illustration 

Remove the white locking pin

Use it to fix the "humidity-sensitive airflow" in the minimum position (see illustration).

Tip: Use your fingers to push the humidity-sensitive bar in order to close the motor-driven damper.

 EHV - indregulering

Register the pressure by fitting a manometer as shown on the illustration.

Look up the initial adjustment diagram in guidance 3004062 (link at right).

Use the registered value to locate the pressure and airflow in relation to the fixed damper position (0-5).


Accessories for EHV fitting

Accessories for EHV fitting

Grease filter EHV-GF

EHV-GF Grease filter

EHV-GF grease filter with plastic frame

The filter is placed over the EHV fitting to create a grease filter in front of the valve.  

Dimensions L x W X D: 185 x 260 x 80 mm

Add all about the product series EHV - Humidity-controlled valves


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