How many cubic meters per hour do I need for good indoor air quality?

Is the second calculation completely wrong? I'm just trying to understand why there are two methods.

Can someone explain to me what the 25 m3 per person is about?

When is this type of calculation used?

And when the one with the room volume x factor 0.3?

Let's assume that not the guest room, but the continuously used children's room has 10 m2 and 26 m3.

Would then in this continuously used room 25m3/h (=because 25m3 per person) be required or only 7.8 m3/h (=25×0.3)?

Are you kidding us? I just explained it.

Is the second calculation completely wrong? I'm just trying to understand why there are two methods.

Can someone explain to me what the 25 m3 per person is about?

When is this type of calculation applied?

And when the one with room volume x factor 0.3?

Let's assume, not the guest room, but the constantly used children's room has 10 m2 and 26 m3.

Would 25 m3/h (= because 25 m3 per person) be required in this constantly used room, or only 7.8 m3/h (=25×0.3)?

If the children's room is constantly used, you are doing something wrong. At least in DE there is compulsory schooling and most children have hobbies.

Of course, you can also oversize, but then you have your fresh air constantly...

Speaking of fresh air. What do you define as fresh air? That also influences your calculation.

×0.3 => room calculation x25 => house calculation

That's how I understood Lumpi.

Yes, depending on what gets bigger. If four people live in a 50sqm house, 100m³/h per hour should be assumed and not just 0.3, so about 30-40. Realistically, it’s more like 140 for 4 people, which makes about 350 cubic meters, which is then also about 100m³/h at 0.3.

The OP would just have had to look further, with on average 8 rooms per house and then assuming 2-4 people per room, to see what would come out in the end; such ventilation systems don’t even exist for single-family homes.

Has the CO2 calculator of the state of Niedersachsen already been mentioned here? You are not allowed to link it, but with the mentioned phrases, you can find it quickly.

Read through, fill out the sizing aid, enjoy :)