I checked into an apartment with ants in the bedroom, living area, kitchen and bathroom. I spoke to the host and they sent a fumigation team supervised by the cleaning lady the next day. I had to tell them to check the living area, kitchen and bathroom, and had to ask the cleaning lady to clean the apartment and change sheets and towels that I saw laying all over the place. She said she was not instructed to do so (although after I saw how the technicians were touching everything it really seemed like the appropriate thing to do, I shouldn't have to ask for that), so I had to write to the host and they sent her back (with a bit of an attitude I must say, I felt he was calling me a liar when I was the one there managing things) to clean and change everything. Later I came back, tried to cook for the first time and found a lot of ants behind the couch, in the pans, dishes and kitchen shelves (together with an old pepper jar with mold). I had to clean as much as I could to eat something there. The bottom line is that the host doesn't really supervise anything, it's a commercial property (nobody lives there) but managed poorly. If you don't have issues you could enjoy the apartment quite fine, but at the first issue you will have to manage it yourself.
The double bed is placed in what seemed to have been a balcony at some point (now closed). The bed barely fits in there. I had the bad luck that there were strong winds in Barcelona for a few days, since that "room" is not completely sealed, I was trying to sleep with a fan on my face all the time, impossible to sleep. On a normal day without wind it's just a breeze you feel on your face coming from the window, that didn't stop me from sleeping.
That "room" is not dark either, if you need darkness to sleep then you have to sleep in the other room with single beds, that one is completely dark but on the down side, that room is very noisy from the street.
The building is old and smells terrible, it really smells like a public toilet. I didn't use the elevator during my stay because the smell was disgusting and making me sick. And the bathroom of the apartment has a window into the elevator shaft (building courtyard where they improvised an elevator), so I also had to keep that closed, I preferred to leave the bathroom door open and the window to the street open.
The apartment is rather quiet, the elevator's engine runs through the night, it's kind of a buzzing sound, it didn't bother me to sleep but if you are very sensitive this may annoy you.