Talk about oblivious to the outside world. I didn't even know these existed. Well, I've seen the built in ones, but not an easy install attachment. Yep, yet another *must have* item discovered here on, apparently temporarily, Poop-Forum.
I was looking at the hot/cold models, but I opine that the water heater is too far away from the bathrooms to make a difference anyway. By the time the water heats up, the recipient will be long gone having completed the task with the cold water in the pipe.