Do system boilers run out of hot water?

This factor is determined by the capacity of your hot water cylinder. You should consider how much water you need for taps, baths and showers when choosing the right size. However, you should keep in mind that the size of your cylinder will rely on the space available. A system engineer will help you design the hot water tank and the system to your ultimate satisfaction and your hot water demand. If calculated correctly, you wouldn’t run out of hot water.