Hi there.
Good question re the air conditioning!! There was a big fan on the ceiling first of all with one could operate by a switch near the bed.
Yes there was a 'machine'for AirCon on the window but to be honest I did not need to try it..so I am sorry I can't shed much light on that, however it looked rather old to me. I only had breakfast at the hostal which was fine.
Hope that helps a bit, as I say a nice place.
The staff were lovely, chatting about the world cup ( I speak Spanish but they seemed to have good English too), lending me an adaptor to plug in my mobile phone charger etc etc
Saludos
James