Oh, and it seems that I can't subscribe to my water heater's events
I can only subscribe to ALL water heater events. Then filter by my device mac address.
So that's right, folks - anyone with a Rheem account can get the real time status of all Rheem water heaters.
Trying to find an MQTT subscription topic for just my water heater.. don't want Hubitat hubs to have to filter.
Jesus!
Thanks for the heads up on this. I was considering a Rheem hybrid water heater. Not anymore.
That's what I just got.. the big boy, 80gal hybrid.
It'll be nice to put it on 'vacation' mode when my airbnb is empty.
I can tell you this... the Rheem app is maddening.
Right now, it's stuck in 'away' mode. Guided tour says tapping on the away icon will switch between home/away, when in reality it just goes into away settings where you configure geofences.
When in away mode, the app doesn't let you set the water heater mode and temps.
Trying to find the API to put it back into home mode.
We just installed this one in our family cottage last summer. It's in the kitchen - 100+ year old cottage and the water heater (since one was added) has always been in the corner of the kitchen, so that's where we put the Rheem. 
Stubborn traditionalists. One side benefit, on a hot summer day when it's running its exhaust fan cools off the kitchen nicely. 
I can't say for sure, but I do remember (or think I remember) changing between home and away from the app, but I'm on Android, and it's been months since I've used the app. We shut down our cottage from late fall until May, so nothing is up and running there now...
I'm considering getting a 50 gal hybrid to replace a 50 gal electric.
Actually, it is data shown below that drive this consideration. My electric 50 gallon heater costs about $250 a year to operate. Based on where I live (New Orleans), I anticipate that a hybrid water heater will run in heat-pump mode 90+% of the time, giving a saving of about $150 a year.
And have the added benefit of making my attic a little cooler, which in turn may keep the upstairs of my townhome a little cooler.
So I think I'll recover the cost of the heater in 10 years or less.
We like our very much, but they are crazy expensive...my dad said "I bought my first three cars for less than that!" 
The build quality does seem to be good. The cooling effect it running is a nice side-effect.
About twice the price of a regular electric.
For example, a Rheem Gladiator 50-gal electric heater with a 12 year warranty is ~$800.
The comparable Rheem hybrid is $1700.
So the cost to recover is about $800-900.
Well, I've made some changes.
When you put the water heater into 'vacation' mode, it automatically puts the water heater's location into away mode.
If you try to put the water heater back into any of the other modes from vacation mode, it'll fail because it's in away mode.
So I made changes that say "if you put it into vacation mode, put it in away mode first, then wait 15 seconds. If you put it into anything but vacation mode, put it in home mode first, then wait 15 seconds"
(I tried with 5 seconds and received the same error. Yay for shitty distributed system APIs!)
So I suppose I'll fork this repo, check in my changes, and figure out how to publish it into HPM :).
Can we get a new thread for this app? It's confusing. It makes it look like dman is the new developer when he's not. I knew that. So when I search for Rheem and saw this thread I then spent another several minutes trying to find a newer thread, but one does not seem to exist.
So I propose
Thanks @waterboysh good idea! Thread moved here: Rheem EcoNet Integration maintained by Kris Linquist
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