There are other questions such as this that ask about a point of use heater to provide quicker hot water, but they don't seem to fit what I want.
Our kitchen sink takes a while to get hot, and I would like this to be more immediate. If I use a small tank water heater (2.5 gal) under the sink, and connect that to the hot water, it seems that I would get 2.5 gallons of hot water immediately, followed by 20 seconds of cool water (the time it normally takes to get hot water) that would then gradually warm back up, right?
What I would love to have is an inline tankless, plug in (120v) water heater that would immediately provide warm (ok if not super hot) water, and then automatically turn off once hot water from the tank arrives so that the water is not over heated.
It seems like such an obvious solution, but I haven't been able to find such a device. Is there a reason why this does not exist?