ᐅ Retrofitting a decentralized ventilation system in the bedroom
Created on: 19 Jan 2026 19:58
F
Flipp147Hello everyone,
I would like to retrofit a decentralized ventilation system in the bedroom of our semi-detached house and hope to get your feedback.
The house was built in 2004 and has an external thermal insulation composite system (ETICS, also called EIFS) (in case that’s relevant).
The main reason is that, especially in summer, I would like to keep the bedroom window closed to reduce unwanted outdoor noise while still ensuring sufficient ventilation.
Initially, I thought that a bidirectional unit with only one duct, meaning a single core drill hole, might be sufficient. I have already had two contractors on site.
One exclusively installs Lunos and suggested the Lunos ego to me.
The other offered me the Blauberg Vento Expert Duo but said he would basically also install other brands.
My biggest concern with this solution – regardless of the manufacturer – is the possible noise level in the bedroom.
The devices each specify a standard sound level difference of about 45 dB. However, I find it hard to assess whether this value is sufficient in practice. Therefore, I worry that the bedroom might actually be noisier with the ventilation system running than without it, even with the window closed.
The sound power level strongly depends on the airflow rate. The bedroom has a volume of about 40 m³ (1,410 ft³) and is occupied by two people. The Lunos ego apparently has a whisper mode, but I wonder whether an airflow rate of about 5 m³/h (3 cfm) is even remotely sufficient. If relevant: the bed is located about 2 m (6.5 ft) from the planned position of the ventilation device.
I am aware that noise and sound perception are highly subjective. Nevertheless, I would appreciate an assessment from people with more experience and technical knowledge.
If it turns out that the solutions mentioned above are not sensible for acoustic reasons, I have also considered an alternative with separate supply and exhaust units in different rooms. As far as I can tell, these unidirectional units are often quieter and also have a higher standard sound level difference.
(Furniture placement in the floor plan does not correspond to reality :-) )
Would such a setup be practical in a typical semi-detached house floor plan? And could the bedroom door remain closed permanently in this case?
Thank you in advance for your opinions and experiences.
I would like to retrofit a decentralized ventilation system in the bedroom of our semi-detached house and hope to get your feedback.
The house was built in 2004 and has an external thermal insulation composite system (ETICS, also called EIFS) (in case that’s relevant).
The main reason is that, especially in summer, I would like to keep the bedroom window closed to reduce unwanted outdoor noise while still ensuring sufficient ventilation.
Initially, I thought that a bidirectional unit with only one duct, meaning a single core drill hole, might be sufficient. I have already had two contractors on site.
One exclusively installs Lunos and suggested the Lunos ego to me.
The other offered me the Blauberg Vento Expert Duo but said he would basically also install other brands.
My biggest concern with this solution – regardless of the manufacturer – is the possible noise level in the bedroom.
The devices each specify a standard sound level difference of about 45 dB. However, I find it hard to assess whether this value is sufficient in practice. Therefore, I worry that the bedroom might actually be noisier with the ventilation system running than without it, even with the window closed.
The sound power level strongly depends on the airflow rate. The bedroom has a volume of about 40 m³ (1,410 ft³) and is occupied by two people. The Lunos ego apparently has a whisper mode, but I wonder whether an airflow rate of about 5 m³/h (3 cfm) is even remotely sufficient. If relevant: the bed is located about 2 m (6.5 ft) from the planned position of the ventilation device.
I am aware that noise and sound perception are highly subjective. Nevertheless, I would appreciate an assessment from people with more experience and technical knowledge.
If it turns out that the solutions mentioned above are not sensible for acoustic reasons, I have also considered an alternative with separate supply and exhaust units in different rooms. As far as I can tell, these unidirectional units are often quieter and also have a higher standard sound level difference.
(Furniture placement in the floor plan does not correspond to reality :-) )
Would such a setup be practical in a typical semi-detached house floor plan? And could the bedroom door remain closed permanently in this case?
Thank you in advance for your opinions and experiences.
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