Heat Pump Water Heater

Did the attic duct help?

I'd think that pulling hot air into the unit would be beneficial.

I have a 1st gen AO Smith hybrid water heater, going on 11 years old now. I'm still quite happy with it. As I mentioned, it cools my garage, and this is really nice when living in South FL. But getting into the truck when the garage is cool really helps, as both my wife and I are heat intolerant now.
I haven't quite made it to the attic with it yet, as it stands now it comes out of the cubby it's in and runs about 6 feet away along the ceiling. Far enough away from the unit so as not to mix the cold exhaust into the intake. I don't have any solid numbers about the effect, but it has got to be slightly better since it gets the hottest air in the garage all the time and doesn't mix with the cold. One day I'll finish getting it up to the attic, that project is just a little further down my list.
 
Funny this came up. I just installed mine yesterday. It’s a Richmond from menards, but is made by Rheem. Looks just like OP’s.

We’ll see what it does to the power bill.
 
Yes, I know I'm really pushing the clearance on this one, didn't have a lot of choice though. With nothing in front of it like that it still appears to breathe well enough.

Least I put an end to the 3 week long ordeal.

I saw mention of it online, and I think it is really dumb of Rheem to plaster that you should be in 'eco mode' all the time. Basically it runs the elements and the heat pump instead of just the heat pump. Only reason I could see that setting being better is if you're in an extremely cold climate, but for me, I'm just locking mine in HP mode and leaving it until winter. I might play around with the combined mode then.

View attachment 95939
You are missing the heat trap for the cold water intake. Might make it more efficient.

image.jpg
 
You are missing the heat trap for the cold water intake. Might make it more efficient.

View attachment 114564
No, I'm not. I used an inline trap instead of building one.

 
ctech,

You could run the flex duct up to the high point in the attic, then put a small fan to blow air down the duct (something like a 5-10 CFM fan would help.... ), put the fan on a relay to turn on when the water heater is running...

You'd pull HOT A** air from the hottest air of the home and the water heater would have plenty of it, even in Winter.

I'm a 100% gas water heater fan boi, but if these HP Water Heaters get better, I might switch. I feel like you could run one fairly easily on a generator.
 
ctech,

You could run the flex duct up to the high point in the attic, then put a small fan to blow air down the duct (something like a 5-10 CFM fan would help.... ), put the fan on a relay to turn on when the water heater is running...

You'd pull HOT A** air from the hottest air of the home and the water heater would have plenty of it, even in Winter.

I'm a 100% gas water heater fan boi, but if these HP Water Heaters get better, I might switch. I feel like you could run one fairly easily on a generator.

Lol, that's a lot of work for what would probably be a little gain.

I'm pretty happy with the setup now, which is why I haven't been in a burning hurry to get the duct punched through to the attic. The intake/exhaust is far enough apart they don't mix, and the garage is usually plenty warm. I'm still going to punch it through to the attic, it is just far down on my list of to-do's, especially since the wife made me drag home 2 jet ski's that need work before we can use them next year.

Yay, projects!!
 
I am late to the game on this deal.
I just tried to order one of these water heaters and the price changes back to regular pricing when I enter my shipping address.
 
I am late to the game on this deal.
I just tried to order one of these water heaters and the price changes back to regular pricing when I enter my shipping address.
They must have realized what was happening. I'm glad I got mine for $999.99
 
Little bit of an update given the single-digit temps we are having here in GA at the moment.

Got up this afternoon and got ready for work, took the usual shower, which requires the unit to run. Not today. Not sure the air temp is that it makes the switch, but the unit is smart enough to not bother running the compressor at such a low air temp and it kicked on the resistive elements (Although, it did report running the compressor after the temp had recovered after a while. It has been locked in 'compressor only' mode since install.). This is the first time I think it has done it as it is a VERY noticeable uptick in power usage. Almost 10 kWh usage today, when we've mostly been in the 5.5 range. I've been plotting usage since I installed it and you can certainly see that it takes more running the colder the air source gets (duh), but the jump is massive when you have to fall back to resistive heat. So, still, a big win in my book if your climate/installation supports it. Once this cold air pushes out in a day or two, I'll be back to compressor-only operation.

It's still on track to pay for itself in just at a year.

Screenshot_20221224-050056.png
 
Last edited:
I'm in Florida and when temps drop I switch mine to the High Demand setting. It uses both the compressor and elements to heat. Not going to help you when its that cold but in milder temps it will keep you from a cold shower. YTD I've used 1336 kWh (approx $143 per year) and that's with 2, sometimes 3 teenaged boys in the house, multiple loads of laundry every day, dishwasher , etc. I am more than pleased with our unit.
 
Another small update (I Guess).

I got bored at work the other night and pulled the data from the unit so I could play around in Excel with it. Interesting to watch the efficiency increase with the unit in my now boiling hot garage. (See the 7 day average in June). Nothing else has changed, still 3 people doing what we do.

Another thing. The dip in May is from us being out on vacation. It reported using just under 1kw/H a day for some reason even though I had the unit switched off, but left it connected to power as I wanted to turn it on to heat on our way back so that we would have hot water when we got home. Next time I'll just cut power to the unit at the breaker box. Not really any reason it should use so much just sitting there with the control circuitry on.

View attachment 105339

Looks like your average is about 3.5 KWH a day.
That would be "about" 1.40 a day here.
 
I'm in Florida and when temps drop I switch mine to the High Demand setting. It uses both the compressor and elements to heat. Not going to help you when its that cold but in milder temps it will keep you from a cold shower. YTD I've used 1336 kWh (approx $143 per year) and that's with 2, sometimes 3 teenaged boys in the house, multiple loads of laundry every day, dishwasher , etc. I am more than pleased with our unit.
That's the thing. It appears that the unit is smart enough to do that all on its own. Whether that is out of protection for the compressor or actually managing to get the water warm I don't know, but it is good to know since I haven't really found it documented anywhere.

We've never run out of water, but our demands are lower than yours. The kid moved out shortly after I put the unit in, so its just the wife and I. Compressor only keeps up just fine for us, even when the temps dip (Current cold snap excluded)

Now, the condensate pump in the garage, that's another story, it froze up completely. Got home this morning and it was just sitting there running, unable to pump anything. So now there's a 5 gallon bucket collecting condensation until it thaws out.
 
We have a 50 gal propane water heater and have the temp cranked up almost all the way so there will be enough hot water to fill Jacuzzi when blended with cold water. It's probably hotter than the max temp of a HP water heater. I would go with an 80 gal HP but wonder if that would be enough. The Jacuzzi is larger than the normal oval one person tub. More like a two person tub. I plan to fill a measured bucket for a min and then fill the tub nothing how many minutes to determine the tub capacity in gallons.
 
Little bit of an update given the single-digit temps we are having here in GA at the moment.

Got up this afternoon and got ready for work, took the usual shower, which requires the unit to run. Not today. Not sure the air temp is that it makes the switch, but the unit is smart enough to not bother running the compressor at such a low air temp and it kicked on the resistive elements (Although, it did report running the compressor after the temp had recovered after a while. It has been locked in 'compressor only' mode since install.). This is the first time I think it has done it as it is a VERY noticeable uptick in power usage. Almost 10 kWh usage today, when we've mostly been in the 5.5 range. I've been plotting usage since I installed it and you can certainly see that it takes more running the colder the air source gets (duh), but the jump is massive when you have to fall back to resistive heat. So, still, a big win in my book if your climate/installation supports it. Once this cold air pushes out in a day or two, I'll be back to compressor-only operation.

It's still on track to pay for itself in just at a year.
Mine has long since "paid for itself". I did run out of hot water yesterday though. I put it from efficiency mode (compressor only), to hybrid mode, and cranked the temp all the way up. It's been unusually cold, down in the 40's here and the compressor runs too long to be effective. But it won't be long before Jupiter, FL is back up to a balmy 80 degrees.
 
Digging this back up since I have a bit of a functional update. Actually, more of a piece of advice for anyone who has bought a Rheem Proterra.

Go ahead and spend the $20 and order a new set of 4 thermistors.


Yours will probably fail at least one of them at just over a year. They are pretty easy to replace provided you can get the top of the water heater off. 10 Screws and you're in. Cut some zipties, pull the old ones and replace with the new. It will probably be the suction side one that goes bad, but they recommend you replace all 4 of them. You'll get an alarm and an A005 error. All 4 thermistors are exactly the same part.

This is a super common problem with these heaters. It looks to be caused by dissimilar metals on the thermistor and the tubing it is attached to.

Rheem will probably send you the new parts if you ask them, but for $20 I don't know if it is worth your time on hold in order to get them for free. I replaced mine and then asked them for another set of replacements so that I have a backup set.

Search Youtube for Rheem Heat Pump thermistor and there are vids showing the replacement.

I also have the troubleshooting guide uploaded here:



If you feel like putting a meter on them and checking them out, but really, just replace them. You'll find the offending thermistor reading in the 2600 ohm area which equates to 148 degrees, even at room temp. This makes the controller think the compressor is way out of spec and shuts it down.

Hope it helps keep someone from freaking out when they get this error.
 
Back
Top