We stayed at Stefano's at the end of August. So the room was very warm. Temperature was between 35 to 40 degrees Celsius (90-105F). There is an air conditioner in the main room with the kitchen but it is weak and not enough to cool the space down. The room is an attic space with 4 big skylight windows in the main area the open. If there is wind, it is nice and does get cooler. If there is no wind, it is very warm. The bedroom and bathroom both have a skylight window that opens. The bedroom has no air conditioning but there is a shade on the skylight. I woke up sweating two of the three nights we stayed. The host was concerned about rain so asked us to keep the windows closed during the day. When we got back to the room it was probably 48 degrees celsius, so we immediately opened the windows. I think if the skylights in the main room had shades then that might have kept the temperature to 37 celsius.
Other than the hot room, it is clean and a nice apartment. It is an easy walk to the main area of Arco and the building has a locked gate to keep your car secure.
Stefano and his wife are very friendly and will try to help you as much as possible.