After all the extra walls are demolished, and the new ones are installed, it is necessary to start the installation of all engineering systems. This is a very important stage, as it includes the arrangement of heating, air conditioning and ventilation. It is very important to understand whether the bathroom will be in each room or it will be common on the floor. Obviously, one bathroom will cost much cheaper, but this reduces the value of numbers. Ventilation, air conditioning and electrical wiring must be carried out in each number. Do not forget about the Internet and cable television. Cosiness in the rooms largely depends on the thoughtfulness of engineering systems and ultimately the success of the enterprise itself.