Rangehood choice / type and ducting for Townhouse

Hey Guys

So looking into rangehoods and found a couple which is good I think.

Going for the undermount design, brands I found are Sirius, Bosch and Schweigen

Now I am guessing best ducting is going to be the wall type.

1. Sirius SL906 EML 850 has external motor SM2 Noise Level 64dBA and 1200m3/h
2. Sirius Internal SL906-L 850 with Noise Level 47dBA and 1020m3/h (there is a 2000m3/h option as well)
   
   
3. Bosch DHL895CAU with Noise Level 64dBA and 820 m3/h
4. Some Schweigen 900mm Undermount - haven't come across a model yet.

1) Which one is recommended? or any other

2) Which type is better - external or internal motor? Noise level baffles me as the internal is rated quieter than external for Sirius.

3) The cooktop is going to be 900mm . But does it make sense to take a 1000mm or 1200mm rangehood so that we can put our thermomix which sometimes cooking rice or something can then easily suck up the steam sitting next to the cooktop?

4) Which airflow rate is recommended?

5) Any other thing we should look at / take care of?

Ta

Just be careful with the external motor models. There are stories on forums about noise complaints from neighbours leading the council directions to uninstall them. With respect to power, the higher the better, and if you have an induction cooktop buy a rangehood that is specifically designed for that. Noise is a huge factor, because if it is too noisy you will not want to use it, which defeats the purpose of it entirely.

Thanks.. Just visited a shop and there were some comments against Sirius baffle filters and recommended honeycomb/mesh filter for gas cooking. Is that true? She was saying on the line that it drips back into the food??

Condensation is the issue with induction, but I've never had trouble with gas. I suppose it could be if the hood was too high and the steam cooled before going through the filters.

Hey

suddenly Qasair is also into play now.. much more expensive but sounded much quieter with indoor motor..

Any recommendations between undermount Qasair / Sirius / Bosch or any other..