Thanks for your help, Gomexico. I'm afraid I'm hooked on the concept of AC. Also, windows that open.
Although I was really interested in Posada Viena and CasaGonzalez, they do not have AC; and I want to have that option in case it gets hot. I also want a hotel where the windows open.
I have spent hours looking at the hotels in this site and reading the forums. My hangup is the AC and opening windows requirements. That gets me into the really expensive properties, which I do not want.
I currently am looking into Mision Zona Rosa. Although it's rated here way up in the 70's (no reviews since 2004), it says it has both AC and windows that open, and the reviews two years ago (3 of them) were good.
Do you know anything about this hotel? I think it's slightly outside of the Zona Rosa area.