As a solo female traveler, I highly recommend Casa Alda. It is a great place to start for exploring Florence in a "local" way. Casa Alda is locating at a quiet and safe zone, little away from the center but it is really convenient to take the bus (15 min a bus for week day, will need to wait a little more at Sundays) or by walk to the tourist site. There are several great little shops around the neighborhood area (Le Cure), local ice cream shop (Gelateria La Carraia) and restaurant (Casa Paloma Firenze) recommended by mr. Maurizio are so nice and at a reasonable pricing. Also, I appreciate Casa Alda is strictly following the sanitizing and security rules for the safety of the guests.
Every morning, mr. Maurizio would stay and talk with me while I was having breakfast, talking about the history and fun fact about different culture. Although, I can't speak Italian, mr. Maurizio tried his best to communicate with me in English and through Google translate. I really like the little morning tour and the bus information mr. Maurizio walk me through, it was really helpful. The room is big and warm, private bathroom is equipped with nice showering facility and toiletries.
I would really love to stay in Casa Alda again if I have the chance to visit Florence again, it is like home.