It's particularly bad with my tankless hot water heater that apparently doesn't even turn on for 15 seconds, and then you wait for the hot water to get to the s

It's particularly bad with my tankless hot water heater that apparently doesn't even turn on for 15 seconds, and then you wait for the hot water to get to the shower. I swear the whole thing takes 60-90 seconds, and I live in a tiny house. I can't fathom what the hot water is doing on its way to the faucet. (well, yeah, some of that time is also spent heating the cold uninsulated under-house pipes).