Both air conditioning units and boilers with condensate removal pumps often get rid of large amounts of water. One way to reduce water usage is by collecting condensate and using this water for other useful purposes, including gardening.
Many installers, when installing condensing boilers and condensate removal pumps, use 22mm hard plastic pipe. After all, it is the standard used for most plumbing installations. However, it can often complicate pump discharge pipe runs.