ᐅ Central ventilation system and odors from outside

Created on: 19 Mar 2017 13:35
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Paulus16
Hello,

We are currently in the planning phase of building a single-family house and are considering ventilation systems.

At the moment, we are renting a place just three houses away from our building plot. Almost every day, I notice a strong unpleasant odor coming from the neighbor’s chimney when I go outside. I am worried about having this odor circulating inside the house if we install a central ventilation system. Are my concerns justified? What can I do about it? Should we avoid installing a mechanical ventilation system with heat recovery?

P.S. We have the possibility to ventilate by opening windows 2-3 times a day. Would that be enough to prevent mold?
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Steffen80
19 Mar 2017 14:48
That is not an issue with a VOC sensor. We install them not only in the supply air but also in almost every room. VOC sensors with 1-wire technology are also significantly cheaper than KNX sensors.
Mycraft19 Mar 2017 15:02
matte1987 schrieb:
If I’m correct, Mycraft solved this using KNX with a VOC (or another) sensor in the outdoor air intake.
When the sensor triggers, the system shuts down until the sensor readings fall below the threshold again.
At least, that’s how I imagine it.

Yes, that’s how it works for me... Generally, modern ventilation systems usually have an input for additional sensors even without KNX, simply for an emergency stop, for example. This could be used to install a VOC sensor that shuts down the system until the odor has dissipated.

Adding an activated carbon filter (in addition) is also not a bad idea...
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Paulus16
19 Mar 2017 15:46
Thank you, Mycraft.
Did you install the system from the beginning, or only after you noticed odors coming from outside? Are there any differences now? Do you know how long the system stays off in that case?

One more question: What is the cost factor for the VOC sensor?
Mycraft19 Mar 2017 16:05
During the renovation of the system in 2014, I added sensors... not only because odors were being drawn in... but also to reduce the amount of maintenance required and to allow the system to operate as automatically as possible, providing the necessary air exchange rates.

The system stays off until the sensor signals that the odor is gone (including hysteresis)... which varies quite a bit.

The price was about 200 euros per sensor, if I remember correctly...
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Alex85
19 Mar 2017 16:15
I would lean more towards an activated carbon filter. In the most affordable case, it’s simply a replacement of the standard filter and starts at around €5. System manufacturers often also offer modules.
Not everything needs to be over-engineered... detecting poor air quality with a sensor to shut down the system is at best a workaround, not a solution.
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Bieber0815
19 Mar 2017 17:47
Both options have advantages and disadvantages. The sensor works well for short disturbances, while the activated carbon filter is effective if ventilation needs to run during longer periods of neighbors burning wood in their fireplaces.

I would always use the activated carbon filter in addition to a “standard” filter. The latter is intended to remove larger dirt and dust particles, with the activated carbon filter behind it to reduce odors (and pollutants). Optionally, a fine filter can be added to help with smaller particles (pollen, as well as soot), although commonly available filters, in my opinion, do not effectively capture fine dust.

For fully automatic operation, I would first prefer a humidity and CO2-based control system. However, such sensors also cost money and need to be replaced eventually.