Have tankless Rinnai--ideas for improved performance
Yes, I have read the incredibly long-running discussions about the pros and cons of tankless water heaters. I don't want to re-discuss 'em. We HAVE a tankless Rinnai, and I want to figure out how to live better with what we have.
Generally, we're happy with the unit. We've made several modifications to how we use hot water, which are acceptable. There's just one main thing I'd like to solve.
The chief issue is the amount of time it now takes hot water to reach the tap in the kitchen. I mistakenly thought a hot water recirculator would solve the issue, but of course it couldn't start up the water heater. I considered the solution of installing a 6-10 gallon tanked water heater in series, but decided against the whole thing for two reasons: (1) the potential for creating a hospitable breeding ground for Legionella in the warm pipes and (2) the fact that it would defeat any energy savings.
I'm now thinking of installing a very small (1-3 gallon) tank water heater under the kitchen sink. Hot water use at the sink is very limited, but in a busy place like the kitchen, when I want it, I want it NOW!
Has anyone done something like this?