No, retrofitting is not complicated, but a little preparation helps. You can easily retrofit many smart home gadgets yourself, for example networked sockets, radiator thermostats, door and window sensors, temperature measuring devices etc. They are easy to install and require no special prior knowledge. However, work that needs to be carried out on the power grid, the fuse box or flush-mounted, for example, must be left to a specialist. The bottom line is that retrofitting a smart home is neither expensive nor time-consuming. You can do a lot yourself, but if you need assistance, a professional can help. You can find installers in your area at here .