It takes about 60 seconds of running the water in the kitchen for hot water to begin flowing, and about 90 seconds to reach the master bath.
What do you think of the recirculation pumps to keep the water warm? How much energy would you think I might loose using a system like this? A timer can be set to recirculate at set times of the day when hot water is likely needed. A dirty calculation tells me I might save 2000 gal of water with such a system.
The other option I'm considering is an instant hot water heater installed under the kitchen sink. It stores about 0.3 gal of water at 170 degrees to be used for tea, or short bursts of hot water to clean dishes. My wife drinks tea every day, and it would be convenient for her to have instant hot water instead of using a tea kettle. Again, how much energy is wasted in keeping this water hot all of the time? Would the energy expenditure be insignificant (less $2 or less /month)? I could put the instant hot water on a timer too.
Would you install the hot water recirculation, instant hot water, or do nothing?
Instant hot water
Hot water recirculation