I bet you are wondering what this red box does! Well its quite simple. Its an inverter which takes the DC current it receives from the solar panels and changes it into an AC current which is usable for home electricity consumption.
After we have discussed how many solar panels you would like installed it is up to you to decide whether you want your inverter inside or out. On the left you can see an indoor 5kW inverter and on the right is an outdoor 2kW inverter inside a waterproof wall mounted box.
It's always good idea to get a larger inverter than needed for your solar panels. If, in the future you would like to upgrade your system you have two choices, either add another inverter or replace the current one. Its your choice. Using a larger inverter from the first installion gives you the option to easily add more panels without having to upgrade your inverter or add another.