I had a wonderful experience staying at Carmens! I did not meet her but her son Ignacio was a kind host. My bus arrived late and I was unable to contact them but Ignacio waited outside the apartment until I arrived. He also got up the morning I left, made coffee and helped me catch a taxi. The room was cozy, clean and located so close to everything. This is my first time traveling abroad and alone and Ignacio made this a comfortable experience. I highly suggest this place while you are in Madrid!