The number of panels you need for your home depends on their type and the size of your apartment. For example, you will need a lot of panels if they are monocrystalline. You may need only one polycrystalline panel for a small roof. It will contain several monocrystalline surfaces to provide energy.
Think about how much energy you need for the house. Then divide the watts by 1000. You will get the size of solar panel surface you need. The number also differs depending on the different characteristics of the panels. To know it better, you should address an expert in the company.