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Installation advice for heat pump water heater

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For those of you with the Rheem 50 gallon unit, how many in a household? We are a family of three and are debating weather the 50 gallon unit is enough or to go with the 65. We take short showers, using about 10 gallons of hot water each. Most mornings we usually all shower within an hour of each other. Washing machine run on cool water cycles so showers are typically only hot water usage aside from dish washer.
Choosing unit volume is like deciding how much range to buy in an EV. The answer is mostly 'the most you can afford, so long as it fits.'
 
Choosing unit volume is like deciding how much range to buy in an EV. The answer is mostly 'the most you can afford, so long as it fits.'
Yeah, and in PA with cool ambient temps and likely cool water inlet temps in the winter, you'll want more capacity to minimize the amount you'll have to run the resistance heat to catch up. I would also strongly recommend installing a thermostatic mixing valve at the same time so you can safely increase your water temperature if needed to increase capacity.
 
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For those of you with the Rheem 50 gallon unit, how many in a household? We are a family of three and are debating weather the 50 gallon unit is enough or to go with the 65. We take short showers, using about 10 gallons of hot water each. Most mornings we usually all shower within an hour of each other. Washing machine run on cool water cycles so showers are typically only hot water usage aside from dish washer.
Would recommend you consider going up to the 65 gallon unit if you can.

We have the 65 gallon unit and are in a significantly warmer climate. Family of 4, but glad we got the 65 gallon unit instead of the 50 and if could do over again might get the 80.

We are on a time-of-use plan and this is probably the future for just about everyone. Nice to be able to bank as much hot water as possible during off-peak.

It's not a big deal, but when we have guests staying over, we have to go to hybrid heat mode and use some resistive heating. Not a common event and not the end of the world, but would be nice to avoid that with the 80 gallon unit.
 
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Thanks all for the input. Waiting for the calendar to turn to 2023 to take advantage of the better tax credits. Hoping my 25 year old tank holds out till then. I’ve leaned to the 65 gallon unit so it’s good to get some validation.
 
It's not a big deal, but when we have guests staying over, we have to go to hybrid heat mode and use some resistive heating. Not a common event and not the end of the world, but would be nice to avoid that with the 80 gallon unit.
Install a thermostatic mixing valve set to 120F, then bump the temperature up to 140F when guests are over and I bet you can leave it in heat pump mode... (I need to do the same thing, and I regret not doing it when I was installing it)

I have to wonder if Rheem updated the firmware on my HPWH to pick up some additional efficiency - the first winter I had it, it seems to go to resistance heat quite often in Energy Saver mode to boost the temp, but it seems way less likely to use resistance heat or run out of hot water in heat pump mode now.

Maybe we just use less hot water?
 
Install a thermostatic mixing valve set to 120F, then bump the temperature up to 140F when guests are over and I bet you can leave it in heat pump mode... (I need to do the same thing, and I regret not doing it when I was installing it)

I have to wonder if Rheem updated the firmware on my HPWH to pick up some additional efficiency - the first winter I had it, it seems to go to resistance heat quite often in Energy Saver mode to boost the temp, but it seems way less likely to use resistance heat or run out of hot water in heat pump mode now.

Maybe we just use less hot water?
We should install a thermostatic mixing valve for safety alone (fortunately no little kids).

Initially we tried 140° in heat pump only mode when having a few guests over but still ran out of hot water. Heat pump only works mostly in summer with guests, but when they visit in the winter we hit cold showers without energy saver hybrid mode. It’s not just more showers but more laundry and more dishwasher running.

We titrate the temperature settings throughout the year to try to avoid cold showers.
 
Anyone else having problems with Rheem EcoNet? Our generation 4 Rheem HPWH is 5 years old now (EcoNet not built in but has external module - prior generation to current models, IIRC).

Every few months the water heater would turn off, seemingly randomly. The app would give the option to “resume schedule”, but the schedule was never “disabled”.

This morning it was even worse, the water heater was and was listed as turned off, but when I went on the app to “resume schedule”, the water heater was still showing as disabled on the unit and app. No loss of connection was reported in the app.

I was able to turn the water heater on via the app, but not by way of clicking “resume schedule”.

Since we’ve had the water heater, I’ve replaced the main router three times (for other upgrade reasons), a repeater router nearby (most recently), and the actual EcoNet module itself. The problem seemed to go away after I replaced the repeater, but alas not so as of this morning.
 
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Anyone else having problems with Rheem EcoNet? Our generation 4 Rheem HPWH is 5 years old now (EcoNet not built in but has external module - prior generation to current models, IIRC).

Every few months the water heater would turn off, seemingly randomly. The app would give the option to “resume schedule”, but the schedule was never “disabled”.

This morning it was even worse, the water heater was and was listed as turned off, but when I went on the app to “resume schedule”, the water heater was still showing as disabled on the unit and app. No loss of connection was reported in the app.

I was able to turn the water heater on via the app, but not by way of clicking “resume schedule”.

Since we’ve had the water heater, I’ve replaced the main router three times (for other upgrade reasons), a repeater router nearby (most recently), and the actual EcoNet module itself. The problem seemed to go away after I replaced the repeater, but alas not so as of this morning.
I have a gen 5 with built in WiFi, this happens too. Sometimes what shows on app is not what is happening on the hpwh. Earlier when I had my schedule to turn off during certain hours, it happens more and I would notice because it did not turn back on. Now, I set it to turn temperature lower so it does not run during certain hours and it seems to be doing better, but it still happened a couple of times. I don’t help any better suggestion, just thought I would share my experience.
 
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I'm about ready to buy a DWH heat pump

Rheem ?
AO Smith (AOS) ?

AOS caught my eye with a 4.02 UEF and water plumbing from the top. That makes the install a trivial replacement I can do myself and not call a plumber.

Two questions are mostly on my mind:
1. Can I reliably set TOU ? For me this is a matter of heating the water during the efficient time of day
2. How much does a 50 or 65 G unit weigh, and can I get it on its pedestal. Or maybe I don't need a pedestal ?

----
By the way, I digged a little into the HP performance and UEF. The latter uses 57F for winter performance (!!!); while the AOS shuts down the HP at below 37F ambient
 
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My Rheem hybrid 65G has been running about two weeks now. So far, outstanding results. We use hot water for two people and have been averaging 1.7 kWh Rheem consumption per day.

I came across the same befuddling advice from Rheem to set the heat pump to 'energy saver' rather than heat pump and decided to ignore it because my 65Gallon tank has a lot of hot water reserve for our use and I'm guessing that the internal programming will not default to heating element usage. The test will happen in the winter with lower ambient. For now it works spectacularly and is averaging a COP of ~ 6 (six !)

Our Rheem is in the garage which has the wonderful side-effect of cooling down the space for free. Funny house, that the most pleasant room in the summer is the garage ;)
I'l have to connect an air supply duct from the outside by the time winter comes along to keep my COP up to desired levels (> 3.0)
 
My Rheem hybrid 65G has been running about two weeks now. So far, outstanding results. We use hot water for two people and have been averaging 1.7 kWh Rheem consumption per day.

I came across the same befuddling advice from Rheem to set the heat pump to 'energy saver' rather than heat pump and decided to ignore it because my 65Gallon tank has a lot of hot water reserve for our use and I'm guessing that the internal programming will not default to heating element usage. The test will happen in the winter with lower ambient. For now it works spectacularly and is averaging a COP of ~ 6 (six !)

Our Rheem is in the garage which has the wonderful side-effect of cooling down the space for free. Funny house, that the most pleasant room in the summer is the garage ;)
I'l have to connect an air supply duct from the outside by the time winter comes along to keep my COP up to desired levels (> 3.0)
so what will be the winter temp in your garage? Why do you pipe in outside air for winter? Wouldn't winter outside air be too cold?
My rheem 80G is in our basement, uninsulated, winter temp about 62F, summer about 66F, I think the inlet temp of water is affecting the efficiency in my case.
 
so what will be the winter temp in your garage? Why do you pipe in outside air for winter? Wouldn't winter outside air be too cold?

In my winter the average ambient is ~ 35F, and the garage would be somewhat the same , not including cooling from the heat pump exhaust. However, peak temps in the later afternoon outside are 40 - 50F most days. I'll set the heat pump to work during that window.

Parenthetically, this is why a large(r) volume tank is advisable for a heat pump water heater. It facilitates these time shifting strategies
 
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