Dedicated Water Heater
As the first step in upgrading the master bathroom, I put a dedicated 20-gallon water heater in the crawl space just below and next to the bathroom.
Along the way, I refactored a lot of piping. I removed a 3/4" hot water line running all the way across the house, which had been added when the attached garage at the north end of the house was converted to a master bedroom and bathroom. It was taking a looong time to get hot water to the bathroom, and wasted lots of hot water in the process.
I also removed a bunch of unused pipe that had been left in place from previous projects. -->
It was an interesting exercise, re-attaching the dishwasher and humidifier lines. I didn't realize at first that the humidier was being fed hot water, although it makes sense; hot water evaporates more quickly, which makes the humidifier more efficient. I discovered SharkBite fittings, expensive but awesome, especially where (a) one can't easily sweat a copper joint without setting something on fire, or (b) one might need to disconnect the pipe later for whatever reason.
In the latter case, a SharkBite fitting on the water heater's hot water line came in handy when I discovered the humidifier requirement; I popped off the fitting, added a tee, and popped it back onto the bottom of the tee.
Note that the tee isn't only for the humidier. The humidifier actually taps into the line via a saddle valve. The additional plastic quick-coupling fitting (not Shark-Bite brand) goes to the dishwasher.
It saves energy feeding the humidifier from a hot water source closer than the main water heater; less heat is lost with a shorter line, and the humidifier is more effective since it's getting hotter water. Previously, by the time the trickle of water reached the humidifier from the far-off main water heater, it was merely warm at best.
Also, while running power to the water heater, I also fixed an ancient wiring mess to the oven.
