When you have formed your idea of a house with the help of achitect the next step is to think about electricity, plumbing, sewing, water supply, heating, ventilation and so on.
What system would fit best to your house? Which is more cost effective and eco-efficient? There is a whole bunch of devices that should be installed in your house according to the certain standards and requirements. For example heating, ventilation and air conditioning are installed before wiring because it is easier to run the latter than the former.