I have a gas heating system that uses a pressurizer. I was told that it makes more water use. It is true?"
This is an interesting idea to discuss. If you do not use a pressurizer, the water flow through the heater becomes small and it heats up much more. You have less water, but it gets to the hotter shower. Thus, in order to obtain the desired temperature, you need to open the mixer cold water valve more. On the other hand, with the pressurizer, the water flow in the heater is higher and, therefore, the heating is lower, that is, the water temperature is in the same conditions, lower. Thus, we have more water from the pressurizer, but in compensation we need to open the mixer valve less. In both cases, we see that the sum of the quantities of water for a given temperature is the same.
