Hello,
Some time ago, we moved into a KFW40 energy-efficient house. The landlord did a lot of the work himself and was not finished with everything at the time we moved in. About four weeks ago, the ventilation system was installed and activated. Since that day, we have experienced significant noise disturbance.
The system operates in two stages, increasing speed depending on the humidity level. At the first stage, the noise is mainly loud in the bathrooms and kitchen. For example: having dinner with conversation in the kitchen is very tiring. When I stand in the hallway on the lower floor, I can hear the ventilation from the bathroom upstairs.
When the system switches to the higher stage, the noise is clearly audible in all rooms. At that point, sleeping is not possible. I measured nearly 50 dB in the center of the kitchen using my phone.
Our landlord claims this noise is completely normal and that we find it disturbing because the triple-glazed windows insulate the house so well.
It seems the noise mainly comes from the fittings inserted into the holes in the wall. When I remove them and look into the open holes, almost no noise can be heard even at the highest stage. The fittings are made of stainless steel and honestly appear to be high quality, not cheap.
My question is whether we (and our neighbors below) are simply too sensitive, or whether he has somehow done a poor job here. From my understanding, it can’t be right to build a house that is pleasantly quiet and then ruin that with such a system. Unfortunately, I don’t know anyone with a house that has this kind of system, so I cannot compare.
Thank you very much for your expert opinion!
Best regards
Some time ago, we moved into a KFW40 energy-efficient house. The landlord did a lot of the work himself and was not finished with everything at the time we moved in. About four weeks ago, the ventilation system was installed and activated. Since that day, we have experienced significant noise disturbance.
The system operates in two stages, increasing speed depending on the humidity level. At the first stage, the noise is mainly loud in the bathrooms and kitchen. For example: having dinner with conversation in the kitchen is very tiring. When I stand in the hallway on the lower floor, I can hear the ventilation from the bathroom upstairs.
When the system switches to the higher stage, the noise is clearly audible in all rooms. At that point, sleeping is not possible. I measured nearly 50 dB in the center of the kitchen using my phone.
Our landlord claims this noise is completely normal and that we find it disturbing because the triple-glazed windows insulate the house so well.
It seems the noise mainly comes from the fittings inserted into the holes in the wall. When I remove them and look into the open holes, almost no noise can be heard even at the highest stage. The fittings are made of stainless steel and honestly appear to be high quality, not cheap.
My question is whether we (and our neighbors below) are simply too sensitive, or whether he has somehow done a poor job here. From my understanding, it can’t be right to build a house that is pleasantly quiet and then ruin that with such a system. Unfortunately, I don’t know anyone with a house that has this kind of system, so I cannot compare.
Thank you very much for your expert opinion!
Best regards
KarstenausNRW schrieb:
More like the other way around. If the same amount of air has to pass through a smaller opening, it gets louder. It might even start to whistle at some point, like with drafty exterior doors and windows.Or like that, yes 😀 We also adjusted everything individually back then.
G
glimmer081519 Jul 2023 07:18Good morning,
thank you for your interest.
The system is located in the attic. It is mounted on the wall there. A standard door. Sound dampers are apparently installed.
The system itself produces almost no noise. The noise comes from air flow at the valves inside the rooms. Mainly at the intake points (bathroom, kitchen), but also at the exhaust points (all other rooms) when set to the highest level.
The system runs on the lower of two settings. I can’t provide more details. When the humidity rises above 70% it should automatically switch to the higher setting, which is then no longer acceptable.
I cannot open the valves any further because the plates would fall out. That’s why we removed some of them in certain areas.
The ducts are inside the walls. I believe they are within the insulation.
I’m wondering what the expected airflow rate of such a system should be for two people in about 130 m² (1400 sq ft). On the internet, I found very different figures: from 30–70 m³/h (18–41 cfm) per person up to roughly 300 m³/h (176 cfm) just for the living room.
thank you for your interest.
The system is located in the attic. It is mounted on the wall there. A standard door. Sound dampers are apparently installed.
The system itself produces almost no noise. The noise comes from air flow at the valves inside the rooms. Mainly at the intake points (bathroom, kitchen), but also at the exhaust points (all other rooms) when set to the highest level.
The system runs on the lower of two settings. I can’t provide more details. When the humidity rises above 70% it should automatically switch to the higher setting, which is then no longer acceptable.
I cannot open the valves any further because the plates would fall out. That’s why we removed some of them in certain areas.
The ducts are inside the walls. I believe they are within the insulation.
I’m wondering what the expected airflow rate of such a system should be for two people in about 130 m² (1400 sq ft). On the internet, I found very different figures: from 30–70 m³/h (18–41 cfm) per person up to roughly 300 m³/h (176 cfm) just for the living room.
C
chand198619 Jul 2023 07:18glimmer0815 schrieb:
In the kitchen, I measured just under 50 dB in the middle of the room with my phone. Even assuming a 10% measurement error, this is unacceptable.
This indicates that the airflow rate at the vents is too high, meaning it is incorrectly balanced, possibly with the humidity threshold set too low.
I thought that for KfW40 standards there must be a report on the adjustment of the controlled residential ventilation system? I might be mistaken.
G
glimmer081519 Jul 2023 07:24We have also wondered whether an official inspection might still be required...
W
WilderSueden19 Jul 2023 07:48glimmer0815 schrieb:
I wonder what the airflow rate of such a system should be for 2 people in about 130 m² (1400 sq ft). I found very varying information online. From 30-70 m³/h (18-41 cfm) per person up to around 300 m³/h (176 cfm) just for the living room. Generally, 0.5 air changes per hour is considered nominal ventilation. For 130 m² (1400 sq ft), that roughly equals around 160 m³/h (94 cfm). Considering two people and the floor area, I would find half of that sufficient as well.
chand1986 schrieb:
Even if I assume a 10% measurement error, this is unacceptable.
It means the airflow rate at the valves is too high. So, incorrectly adjusted, possibly the humidity threshold set too low.
I thought for KfW40 standards there must be a protocol for the regulation of the mechanical ventilation with heat recovery? I could be wrong. Hi, we built a KfW40+ house with mechanical ventilation with heat recovery. The system was, of course, calculated and we partially adjusted it ourselves. The plumber lent us a device (an anemometer) for this. However, there was apparently no mandatory adjustment (at least I never read or was informed about it anywhere). In 2 out of 4 residential units, the system was later measured and adjusted by the plumber. But not in my two units (because my settings were already adequate). I programmed the system "somewhat" myself, meaning I set the times when it should run quietly (level 1) and when it can run louder. Naturally, the system runs faster in the morning after showering.
I would definitely check the filters (especially in the extract air valves, they should be checked and, if necessary, replaced every 6 months. The unit price for good “third-party replacements” is about 1–2 euros for the approximately 8cm (3 inch) round white Helios standard filters).
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