Controlled residential ventilation - Is stage 7 out of 9 an acceptable design?

also 55W is still quite a lot I think, 105 a catastrophe.. One of the most important measured values should be the CO2 concentration though. Have you ever determined it? Our system operates variably between 3 and 5V, in the morning shortly before getting up a shock ventilation runs with 7.5V.

Well, actually it was not to be expected, at least not by me. The attic is basically inside the envelope. The roof (above the attic) has 24cm of insulation. Down to the living space there are only 6 or 8cm. One could think that more heat rises from below than escapes outside, right? The reason for this is not clear to me, it could also be due to a deficiency. But that’s how it is now anyway.

even 55W is still quite a lot, I think, 105 a disaster.. One of the most important measurement values should be the CO2 concentration though. Have you ever determined that?

Have you measured your consumption? As I said, the actuator does not measure very accurately. I still think the value is realistic. Take a look at the data Helios provides. At my current 5.5V that's estimated to be 35 to 40 watts, at 7.5V about 65 watts. Both with 0 Pa pressure loss! Realistic would rather be 100 Pa and with every Pa the consumption increases. I have quite long pipe runs. And the system unfortunately is not properly calibrated yet, hopefully a few watts can still be saved. But the opposite could also be the case. I don't have a CO2 or VOC sensor, no. I rather go by my nose.

You can also buy quite good and inexpensive devices to determine this (<100€). I logged the CO2 concentration in every room over 2-3 days when I adjusted the system. I have the controlled residential ventilation (also Helios) on a separate electricity meter, which is also logged. During the day it is about 750-800 watt-hours, so around 30 watts on average. Pressure losses are also quite high for me (I think it was 180 Pa), because a 50m long LEWT is connected before the controlled residential ventilation.

Hello,
in principle, the device of a central ventilation system is ideally designed for about 50%. That means, for example, with a calculated nominal ventilation of 180 m³/h, you always have to add the static pressure of the system. Usually, the system then runs at about 200 m³/h. The device should therefore deliver between 350 - 400 m³/h. Then the device operates very quietly and efficiently. This way, there is also plenty of room upwards with regard to the intensive ventilation stage.

How is the volumetric flow rate calculated? It should only depend on the number of inhabitants (+dog, cat, opossum, ..) and not on the area.