This is a really lovely old house in the Balat/Fener area of Istanbul - an area which has preserved its traditional character, and which is now becoming fashionable with many nice cafes and restaurants, but still many traditional businesses too. The area has very steep, narrow, cobbled streets (so be prepared for the exercise). In terms of access and travelling around, it's a good 20-30 minute walk to the metro. But travel is easy if you can master the local buses (which are very frequent and depart from the bottom of the street), or prefer to use Uber/taxis.
The house itself is on 3 floors and has been nicely restored. The highlight is a really well equipped kitchen and comfortable adjacent dining area - if you enjoy cooking, you will have everything you need to make even the most sophisticated meal!
The bedrooms and beds are comfortable, with plenty of storage space for clothes. The main bathroom is huge, with a lovely tiled floor. As others have noted, the shower does tend to spray over the floor easily, but Ozkan indicated there are plans to fit a screen, which will be a big improvement.
The house has a heating system for winter, with radiators in each room. It works fairly well to heat up the house in the middle of winter, except for the bathrooms where neither radiator seemed to work. The large main bathroom has a heated towel rail but that struggles to warm such a large space. Hopefully these radiators can be fixed, as the bathrooms are pretty chilly in winter. There are air con units around the house for cool air in summer.
Wifi wasn't particularly fast, but it worked reliably. There is a washing machine in the basement, which was a bit temperamental but very useful for longer stays. And the house has a fine collection of books if you don't want to venture outside.
Overall the house is really great, in a lovely location, and apart from the minor issue of a cold bathroom (in winter) is a perfect place to stay. Ozkan was an excellent host - very friendly and helpful and welcomed us warmly on arrival. We would strongly recommend this house and would definitely stay again when visiting Istanbul.