We spent here one month. This house has a lot of potential, but we can't say we were really comfortable there. The house is beautifully located in the upper part of Belem, which is great if you want to explore a more laid-back and traditional (albeit still quite touristic) part of Lisbon and, like us, don't mind going up and down some Portuguese-style steep streets :).
The main problem is not that the house is small, but that it's full of stuff (books, figurines, paintings, lamps, furniture...). There is an oversized trunk/chest with the owner's belongings occupying 1/3 of a small hall that only leaves room for the smallest sofa from Ikea. There's also a piano. While I am a composer and was happy to know there was a piano in the house, upon arrival I realized that's something such a small house cannot afford to accommodate. The suitcases of the owner were under the bed, which is also too big for the room and put against a wall, so it's not easy to do the bed every morning. These are just examples. Ana needs to decide if this is an AirBnB apartment or her own house (or the house where she keeps her family's stuff). It can't be both with this small space. Less stuff, and choosing different furniture, can really let this lovely house shine.
The house was also not clean, especially the kitchen, when we arrived, so we had to clean it, and some things needed some work/renovation (the bathroom handle was about to fall, the countertop has a crack under the glass-ceramic.
On the other hand, for long stays, you have (literally) everything you may need, from coffee machines to dozens of cups, glasses, dishes, and cutlery.
Overall, Ana is a great guest. Quite responsive and always there to help when there was a blackout or similar.
We personally think this place is just in need of a little bit of love to make it the perfect place to stay in Lisbon. It may be a great place for just a couple of days to explore Belem.