I am typically the first one in my house to take a shower and I like hot showers. I have noticed that if I take a shower first, the hot water is not that hot and doesn’t last very long. But if others take showers before me and the hot water has to recharge then the hot water is HOT and lasts a long time.
I have a 50 gallon hot water tank.
The only two things I have (besides sinks and showers) that use hot water are a dumb dishwasher and a dumb washing machine.
What I was thinking was to set up an automation in HA to somehow trigger something to use hot water for like 10 minutes in order to get the hot water heater to recharge.
Any ideas?
Look into hot water circulating pumps.
They may be retrofit into existing home plumbing, are designed to address this exact use case, can be automated (old school timer or more intelligent with a smart switch), and will be significantly better for the environment/ your water bill. Essentially, there’s a pump located in your hot water tank closet and a small valve installed under your bathroom sink tap. They cost about $100 (though they say that’s recouped quickly because you’re not letting cold water run as long anymore), though you’ll likely need a plumber — it’s straight forward and common.
Now attached to a smart plug you could trigger it to turn on 10 minutes before your morning alarm, not run when you’re on vacation, run when your location leaves the gym (assuming you shower at home), etc.