The only positive aspect of this experoence was its location to central Madrid -- walking distance to everything.
TL;DR - Only stay here as a last resort.
The co-host, Luciano, met us in the apartment to check in around 18:00 and was unwelcoming and a bit off-putting from the first moments of our exchange, starting with the greeting (E.g., in response to, "Hi, Luciano?" to confirm he was the person I was looking for after entering the building following a 6-hour drive, his response was, "Second floor, third apartment."
He honestly seemed annoyed by the entire process even though we were checking in at a reasonable hour. He then entered the apartment with us and made us complete a form in front of him for Covid before he'd leave, as if we couldn't be trusted to take care of it on our own.
The apartment itself has been poorly cared for and is very, very worn. It's certainly no "design" apartment. The kitchen was poorly equipped and the forced-air vents had an entire season (or twos) worth of black dust hanging out.
The bathroom has a rusted old towel warmer style radiator in the shower, and we had no hot water the first night for longer than 4 minutes. After that, we were lucky to get 5-15 minutes of water hot enough to shower in even though the hosts insisted it should never run out. The other host kept insisting this has never happened and wanted to come by to check it out, but we refused the additional inconvenience of his interruption -- we were told the entire building shared hot water, so it seemed there was nothing for him to possibly check in the apartment, besides valves and a fuse box, which I'd already inspected...
Only 1 of 3 table lamps in the living area functioned, the couch was stained and run down showing heavy use, and there's no smart TV.
The heat in the bedroom was excessive and the radiator was locked so it could not be adjusted.... it was very difficult to sleep with temperatures somewhere in the 80s (F).