The room/house has all the conditions you might ask for, and it's very well located. 10m walk up the street and you're in the major museums area, Atocha, Retiro, ... and 10m walk down to Matadero. The Metro station is just nearby, in case you need to spare your legs.
David was very helpful checking us in and full of suggestions for Madrid. Cool. The map he gave us was always in hand.
Thank you David.