Don't know about your air conditioning question but ATM's, the nearest is Sidari, about the middle of the town. There are 2 of them, look for the Kodak photo processing shop, you wont miss it its large big yellow adverting sticks out like a sore thumb. The ATM's are about 2 or 3 shops either side of it. I believe there is also one in Acharavi (not sure if I spelled that right) past Roda.
Have a good holiday you'll like it.