Hello Forum!
I wanted to discuss air exchange rates and, more generally, your indoor air quality. Especially now in winter, we rely about 99% on our ventilation system and only rarely open the windows (for example, after cooking).
Our system is a Zehnder Q350 and usually runs on level 1. According to the app, this corresponds to about 160 cubic meters per hour.
I read that a person needs approximately 30 cubic meters per hour of fresh air. So, if two people are in a room, they would need 60 cubic meters of fresh air. But the system only supplies 160 cubic meters distributed over the whole house. Does that mean the air quality must slowly deteriorate?
This is exactly the phenomenon I can also measure. I bought a CO2 meter from Amazon that shows me the ppm.
It reads 470 ppm in every room in the morning, which matches outdoor air quality. After a few hours, the value rises to about 850 ppm. Then it stays relatively stable, probably because we leave the room regularly.
When I set the ventilation system to level 2, about 220 cubic meters per hour, the value decreases slightly again.
How do you handle this? What ventilation rates do you use, and have you had similar experiences?
Good luck
I wanted to discuss air exchange rates and, more generally, your indoor air quality. Especially now in winter, we rely about 99% on our ventilation system and only rarely open the windows (for example, after cooking).
Our system is a Zehnder Q350 and usually runs on level 1. According to the app, this corresponds to about 160 cubic meters per hour.
I read that a person needs approximately 30 cubic meters per hour of fresh air. So, if two people are in a room, they would need 60 cubic meters of fresh air. But the system only supplies 160 cubic meters distributed over the whole house. Does that mean the air quality must slowly deteriorate?
This is exactly the phenomenon I can also measure. I bought a CO2 meter from Amazon that shows me the ppm.
It reads 470 ppm in every room in the morning, which matches outdoor air quality. After a few hours, the value rises to about 850 ppm. Then it stays relatively stable, probably because we leave the room regularly.
When I set the ventilation system to level 2, about 220 cubic meters per hour, the value decreases slightly again.
How do you handle this? What ventilation rates do you use, and have you had similar experiences?
Good luck
N
nordanney19 Oct 2020 09:44Bookstar schrieb:
In the morning, every room has 470 ppm, which reflects the air quality. After a few hours, the value increases to around 850 ppm. Then it remains relatively stable, probably because we leave the room. I don’t understand. If you are at home during the night, the air quality is good. Then it worsens even though you are not in the room?
Hi,
Our E350 runs continuously on level 1 (160m² (1720 sq ft)) except usually in the evening after cooking/eating when it runs for 2-3 hours on level 2 (210m² (2260 sq ft)). We are very particular about fresh air and are very satisfied, although I haven’t tested it yet with a CO2 meter.
We visited friends on Saturday who live in a new build without a ventilation system, and you can already smell a burst of stale, stuffy, humid-warm air as soon as you reach the front door...
Our E350 runs continuously on level 1 (160m² (1720 sq ft)) except usually in the evening after cooking/eating when it runs for 2-3 hours on level 2 (210m² (2260 sq ft)). We are very particular about fresh air and are very satisfied, although I haven’t tested it yet with a CO2 meter.
We visited friends on Saturday who live in a new build without a ventilation system, and you can already smell a burst of stale, stuffy, humid-warm air as soon as you reach the front door...
Bookstar schrieb:Do you sleep outside the house at night, or how should that be understood?
It measures 470 ppm in every room in the morning, which is the atmospheric quality. After a few hours, the value rises to about 850 ppm. But then it stays relatively constant because we probably leave the room.
Mycraft schrieb:
CO2 and VOC sensors in the system and/or rooms that then continuously adjust the ventilation automatically. That way, you never have to manually adjust them again, and the air is always exchanged in the necessary amounts. This won’t handle peak situations as described (two people in a small room for several hours), since the rooms are not individually controllable. The result would just be the system running continuously at a higher level.
On the other hand, 850 ppm is not a dramatic value. Perhaps measuring it at all is not that helpful without a reference for comparison.
I am very satisfied with our controlled residential ventilation system. I vacuum the central filters once a month, and the decentralized exhaust filters... well, I’m a bit lazier there. So far, it runs well. Also have a Q350 with enthalpy exchanger, running at about 185-190 m³ (6500-6700 ft³).
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