When I start my Stilo after a few days at 0°C or lower I get a weird whining noise inside the cabin for a few seconds, that doesn't seem to be related to rpm (or so it seems).
I recorded this video if it will help... It's not a very good recording, but please wait until the end when the whine stops and you can hear just the car idling, so you can compare... I revved the car up to 2kRPM during the recording, but it doesn't affect the noise.
My question basically is if this is something I should be worried about?

is it heater fan speed related?

It doesn't seem so, as the fan is practically not working when starting a cold car... But I will try to turn the car on with climate control turned off to be sure...

Is the noise coming from under the bonnet or inside the cabin?