How to find an apartment in Zurich

Let's begin saying that most of all the house in Zurich haven't a private owner but they are of companies. They always try to keep them well and they renovate them constantly. That's way, for example, that I don't have a balcony at the moment, because they are remaking all the building balconies and also the facade. They do these things continuously so they can maintain the house rent costs.