I have been looking into tankless WHs lately partly because the way my current NG water heater thermostat behaves. The temp at the nearest tap just after a heatup cycle is about 132. But the burner doesn't kick on again until it drops to about 105. This is too cold to get a hot shower after passing through 3 floors of copper pipe. Yes, I can jack the thermo up to the top and the band is something like 140-112. Still marginal for a good hot shower in the winter. Basically, the only time I have hot water is after I have used some. So I have been checking the temp in the AM and when it's low I run enough water to activate the WH. Then all is good.
I have never had a gas WH before and I wonder if this is typical behavior for the old bimetal style thermostats. If not, what is a proper and typical control band? Are the new self-powered digital electronic gas thermostats, like the Sears/Honeywell any better at this? Are they reliable?