Air exchange rate based on standard values unrealistic?

Hello

I am currently trying to calculate the air change rate for the individual rooms in my single-family house. Since I couldn’t really find out how to calculate the air change rate (1/h), I looked at the table with the "standard values". For a kitchen, it specifies 6-10 1/h. That seems very high to me. With my 20m2 kitchen, that already amounts to over 400m3/h volume flow. The currently installed central ventilation system can’t even manage that.

Can that really be correct, or how can I calculate the air change rate better? Is there a formula for that?

If you want to determine the ventilation losses for the heating load, you can calculate with 0.2 - 0.4/h. The Austrians use 0.2/h for determining the heating load, according to German DIN it is 0.4/h.

If you have no obvious outdoor air inlets or leaky doors/windows, these are realistic values.

If you work with a ventilation system with heat recovery, you can calculate 10% leakage without heat recovery and 80% heat recovery rate.

6.0/h is only used as a rate for testing airtightness with 50pa pressure difference (Blower Door Test).

The standard values are rather too low. Usually, the airflows are also poorly planned. Design the system significantly larger and operate it in partial load range; this is quieter and more energy-efficient.

My problem is that we have a ventilation system that was probably never calibrated by the installer, and I also have no documents for the ventilation planning.

I still have a flow meter here and hoped to do it myself. I just need to somehow calculate how much airflow I need per room.

Bedroom is most important. There is usually too little throughput here. Distribute the rest evenly. If after some time you notice that it is too much or too little, you can readjust.