We loved this apartment, especially the location. La Cava Baja is right behind the apartment and has amazing tapas bars. All the other attractions that we covered during our stay were within walk in distance. The apartment is small and cozy (works perfectly for two people). There are two heaters in the apartment, one in the living room and one in the bedroom. The kitchen is a little tiny, but we did not cook a lot since we were surrounded by such wonderful restaurants !
As other reviewers have suggested, the street does get noisy over the weekends, but you can barely hear it when the blinds are closed. Meyling was super helpful and always responded promptly. The location of the house allowed us to spend a lot more time exploring Madrid. If you don't mind a little noise and climbing 4 storeys , do yourself a favor and book this apartment. You will not regret it.