<font color="blue"> Have a switch placed in the master bath and/or other locations you deem necessary that will turn the re-circulating pump on and off when you need it. </font>
Cowboyjg,
Excellent idea! But, now you have me thinking (dangerous, I know). Can we take your suggestion a step further and put the recirculating pump on a programable timer (something with a manual over-ride, perhaps)? As you mentioned, with little effort, we could probably determine when 90% of the hot water is used and set the timer accordingly. Heck, something as basic as a pool pump timer might work. But being the geek that I am, I'm now thinking digital - maybe like a programable thermostat with weekday and weekend modes. As my father-in-law like to say, someone please step in an protect me from myself. /forums/images/graemlins/grin.gif
Your main point, though, is well taken. Does not make sense for the pump to run continuously when no one is home or when everyone is sleeping.
Also, I'll check with the plumber about 1 large vs 2 medium heaters. Your arguement, again, makes sense.