I cannot recommend this apartment and host enough. I can say without a doubt this was the best Airbnb experience I have ever had. The apartment is located in an amazing barrio of Madrid where there are no tourist (a huge plus in my book) and it is only a block away from the Retiro park. It is also near to several metro stations, such as Príncipie de Vergara and Goya ; so you're only a couple of stops from the Puerta del Sol and the Plaza Mayor. There is no AC in the apartment, but I can honestly say I didn't miss it even in the heart of summer. There a multiple windows throughout the "piso" which allow for a nice breeze to flow through aided by the fans in the den and two bedrooms. The beds are comfortable and the kitchen is stocked with everything you might need including a washer/dryer. The piso is on the 4th floor (European), but there is an elevator.
As far as the host, I feel like I've made a new friend. Jesús came to meet me the day after I arrived and took me around the neighborhood showing me places to eat, drink, shop, etc. I've never had a host do this for me. Then, he took me to an authentic Austurian restaurants to have cider and some tapas. We talked for a little more than two hours about politics, history, literature, traveling and more (all in Spanish). When my husband arrived, he took us out again because he wanted to meet him. We went to another local tapas bar and spent another two hours or more chatting, in English this time. In addition to his amazing hospitality, Jesús was always available via WhatsApp and actually lives in the same building in case you have need of him for anything.
In short, if you go to Madrid, you must stay in Jesús' apartment. You will not regret it. I'm ready to go back to Madrid and stay there again.