Hot water recirculating systems

[bagekko]

I will never have a tank water heater ever again. Have a Navien tankless which is amazing, large house so some faucets will take a minute to get hot. Only thing I considered was adding a quick thing at the kitchen sink.

[Chick Webb]

Originally Posted by M_Six

I've been thinking about using a smart plug for a pump for the same reason. I don't use Siri, but I can set it up in HomeKit to turn on at 6AM and off at 9AM, then back on around dinner time for an hour or two. So it would only be running a few hours a day.

How long do you have to wait once the pump turns on before you have hot water?

It takes just a couple of minutes for the water to get warm enough to start the shower, generally. The pipes are under the house and insulated, but when it's cold (low 40s, high 30s) you've not only got to displace the cold water in the outbound pipe leg, but you have some transfer of heat to the pipe itself. So it takes a little longer then, but not much.

Timers work, of course - the previous owner used one - but HA is ideal in this case. Our kitchen is close to the water heater so we don't need the pump for that, just the two baths down the long hall. That's why the voice control to turn it on/off works well for us. I tell the girl to turn it on when I finish my coffee and by the time I get to the bedroom and am ready to jump in the shower it's ready to go. I generally turn it off (by voice) after I get out, but if I don't the watchdog takes care of it for me. I'd guess that the pump runs for less than 30 minutes/day, on average. Not sure what that saves us in electricity/gas, but suspect it's notable.