I have a Rheem Heat Pump water heater and am using their Econet system to connect to Hubitat.
Heat Pump water heaters are terrifically efficient, but slow to recover. There is a boost mode (High Demand Mode) but there is no automatic way in the native Rheem device to switch between modes when needed. I also don't like to chill the basement in the winter, so I switch modes. based upon outdoor temperature.
I automated this in Hubitat using washing machine usage, and weather as conditions. First rule sorts out power usage of washer, and sets Private Boolean. I did this in a separate rule so I can reuse the PB in other rules.
We are also looking to get a new hot water heater soon, to replace our soon to be 12yr old 30 gallon tank in our basement.
Was wonder if getting the added features that a "Smart" hot water heater provides in today standard's, is really worth paying for. I know some companies add the word "Smart" and an app to their device just to show you basic info, but does not allow you to manages anything from the app.
Don’t know if you want to bother here. Do you travel a lot, to where it would be really convenient to be able to remotely turn it on and off? If not, you just turn it off when you go on vacation, and then just deal with the 45 minute wait when you get home before you can take a hot shower.
I had always wanted an on-demand hot water heater, and thought that would be the most efficient way to go, but after much research, and talking to owners and reading reviews, the general census was DON’T DO IT. Most said they are very complicated and have poor reliability. So much so, that they either don’t last as long, or you end up far exceeding any savings with the repair costs.
We ended up buying a Rheem Platinum with a 10 year warranty. It’s a 40 gallon with an automatic vent that reduces heat loss up the flue when it’s not heating. Did my best to avoid anything with a noisy power vent, which was a big complaint I saw in my research. We’ve had our water heater for four years and it’s been great. No more cold showers, even when I still had a teenager living here
If you really want to add a remote controller to it later you can, but a module for it is something like $100. It’s WiFi and I do not know if I’d trust the security of a Rheem WiFi product. Not their expertise, so you know they farmed it out to some other company and wouldn’t have a clue if it’s actually secure or not.
I made mine smart by turning it on when any of my shower light switches turn on or by asking Alexa to turn on “hot water”. Then we wait a few minutes and have a hot shower. With my old tank water heater I had a simple circ pump connected to a smart plug that I toggled. We went tankless several years ago and the circ pump is controlled by a module in my master bathroom. I soldered wires on both sides of the button and using a dry contact relay I virtually press the button now. So far working great.
Like others in this thread, I too have a Rheem heat pump water heater and it has been fantastically efficient. I actually switched from natural gas to electric, because the cost of a more-efficient NG water heater would still be higher than the switch to electric (admittedly because we had existing plans for electrical/chimney work that supported the switch).
I only use the smart features in HE to adjust the setpoint lower when we're away, turn off when mode is "Vacation," and I have a rule for my wife to use when she wants to take a bath. When a button is held, sets the water heater to high demand mode (resistive heating) and sets to 135 degrees -- sends a notification when it's ready, and then eventually switches back to heat pump mode.
I have one of the 1st model GE heatpump water heaters and love it. It has built in vacation settings as well as fast recovery like a regular water heater. Have never tried to use with my Hubitat though. Well worth the extra money. Use to be able to get state and federal refunds for purchasing.
I have a Rheem 50 gallon and a few rules as well. The biggest rule that I have is to set the water heater to 90 when I'm either away or between the hours of 10:30 PM and 5:00 AM. I also use the Maker app and have a shortcut on my iPhone to set the temp and start the water circulation pump if I need a hot shower as soon as I arrive.
If you're away for an extended time, from the perspective of a microbiologist, I would suggest turning it off entirely because 90 degrees Fahrenheit is pretty much the optimal growth temperature for Legionella pneumophila (the etiologic agent that causes Legionnaires’ Disease).
I would also suggest that setting the "active" temperature to be ~130-132 degrees; Legionella dies much faster at that temperature relative to 125 degrees. This only becomes an issue if water heaters are regularly shifted to temperatures that are permissive for Legionella growth (~70-120 Fahrenheit; optimal is ~90-110 Fahrenheit).
Here's a crude temperature chart for Legionella dormancy/growth/death:
As with most infectious agents, these suggested guidelines matter a lot more for the very young, who have inchoate immune systems, and the aged, who are somewhat immunocompromised.
I also control both my water heaters using Hubitat. Their thermostats are set for 135 degrees. They go on for ~1 hour every morning and every evening. The rest of the time they're off. I drain the tanks once a year and treat the bottoms with ~0.1% hydrogen peroxide for a few hours at that time.
This was my first thought. Rather than turning off for vacation mode, I set it to 55 degrees. Effectively off, and I seem to recall reading this is what many water heaters do in vacation mode to prevent any risk of freezing. I have ours set to 130 about an hour before anyone would use hot water, and reduces to 120 during the day -- but, the tank is so well insulated that it doesn't get much below 127-128.
One of the reasons I like my on demand gas water heater. I can set it to 120F, and not worry about legionella (it can support 2 showers with no cold water blend, so lower water temp is not an issue).
With my last tank (gas power vent, 50 gal), I cranked it to 140F because I did not want to take a chance with these nasties. Unless you are away for loooong periods, I would say get the best insulation available, and/or get a blanket, insulate your exit pipes, set it at 135F + and just forget about it. Not worth it to take a chance with your health for literally a few dollars a year IMHO.
Wow. This is so completely opposite my experience that It's hard to even compare!
I installed a Rinnai On-Demand (propane) water heater in 2009 , and it's been utterly reliable. I run it on well water, with moderate mineral hardness.
Saving money? Probably not a lot. Up front costs were fairly high, and Propane is a bit more expensive than Natural gas, so that's a factor.
Lifetime? So far...10+ years. Repair costs: $0 so far. Operating Cost? Highly dependent on propane cost.
Efficiency? I've got mixed feelings on this. The boiler is highly efficient, but overall efficiency? I dunno, electricity is cheap. But, I don't pay for hot water sitting in a tank. So, who knows?
Bottom line though, the hot water just doesn't run out, Which frankly has WAF through the roof.
