Heat Pump Water Heater

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I have installed several of them in my area. They run a long time to make heat but don't worry it will save you money. And if needed you should have the option of using resistance heat in extremely cold weather if needed. Be sure that it is not in a closet. They need a lot of air to perform efficiently.
 
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Finished project

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ctechbob

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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.

After Rheem Heat Pump.jpg
 
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ctechbob

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So, first thoughts.

Yes, recovery is much slower, we all knew this was going to be the case. The trick is making small adjustments to your daily schedule in order to keep things as 'normal' as possible. In our case, that means just making sure to do laundry and dishes after daily showers. Not a big deal since we're pretty random about doing those things anyway.

With my tank set to 130 deg the wife came home at about 1430 and took a shower, and then I was up at 1600 and in the shower, both of us had plenty of water to finish. At 1950, the unit is still recovering but it is almost completely there, and I bumped the temp up to 135 as well, so it is taking longer from that.

From midnight till now, the app is reporting just under 4kWh used. That includes a total of 3 showers, 2 loads of hot laundry, and a load of dishes. I have some pretty good data from a while back when the HVAC was not on, and no other power was being used except perhaps the fridge, that one of my showers used right near 4kWh of power.

In a nutshell, what I used to pay in power to take one shower, is now stretched out to cover the entire household for 24 hours' worth of 'normal' hot water use.

Big thumbs up from me currently. Even better when the $500 EMC rebate comes through. I will have scored the energy savings for less than it would have cost me for doing another normal electric tank.

Also, as an aside. I can see why PEX is popular these days. It is super easy and fast to work with. I did all mine and crossed my fingers, not a single leak to be found. The only special tools you need is a cutter ($8) and crimper ($20), neither of which is crazy-expensive. The fittings aren't as cheap as you'd find from PVC but they're not ungodly high either. I'm going to have a look at my main water supply next and maybe replace the crappy valves with ball valves.
 
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NE,Ohio
I love working with pex did 4 well tank/pump installations.

If you feel like you need a bigger tank or start running out from 3-4 back to back showers
you can always set it higher to 140+ makes that hot water go way farther when its 50% cold mixed in vs 33% at the shower.

I could easily see you saving 30$ a month with your usage and climate.

That install looks a little borderline, but IMO it should be fine for an atlanta garage.

maybe not so great for a 50F basement. I suppose you could always put a 5-10watt mini fan out there to get more circulation if needed.
and maybe a flange on the exhaust to make sure its all going towards the exit.
 

ctechbob

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maybe not so great for a 50F basement. I suppose you could always put a 5-10watt mini fan out there to get more circulation if needed.
and maybe a flange on the exhaust to make sure its all going towards the exit.
Yep, I'm thinking about baffling the intake from outlet, just to keep it separate, but I agree it is tight. I would have liked to have some more room, but I can't blow out that wall since my laundry room is on the other side of it. Thinking of just coming off the top of the unit out to where the space opens up into the garage, just a small shelf-like piece.
 

ctechbob

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Lol, it never ends. Woke up this afternoon to another water heater sitting in my driveway. The order that was canceled last week finally got delivered. I'll be toting it back to the local HD store because I promised the manager I would when he was helping me out with the whole ordeal.
 
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Consider bumping the temp to over 140. Even if it's just once in a while. Bacteria can grow in water under 140. Also, it helps with the amount of available hot water.

I removed a propane water heater.
I now have a first generation AO-Smith 80 gal hybrid water heater. It air conditions my South Florida 3 car garage! I think I installed it about 2011. It's been excellent, and I was able to remove the 12,000 btu window AC in my garage. Not only did I eliminate a $5.50 per gallon propane bill, but my electric bill went down, as I was no longer running the window AC 24/7.

I do run the temp at 140 in the summer and 150 in the winter. I have a 2HP, three-stage shallow well pump that produces 100PSI, and a 6 showerhead, 2 person shower. So I use a lot of water.

Mine consumes about 650 watts when running. I do not use the resistance heating elements.
 

ctechbob

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Consider bumping the temp to over 140. Even if it's just once in a while. Bacteria can grow in water under 140. Also, it helps with the amount of available hot water.

I removed a propane water heater.
I now have a first generation AO-Smith 80 gal hybrid water heater. It air conditions my South Florida 3 car garage! I think I installed it about 2011. It's been excellent, and I was able to remove the 12,000 btu window AC in my garage. Not only did I eliminate a $5.50 per gallon propane bill, but my electric bill went down, as I was no longer running the window AC 24/7.

I do run the temp at 140 in the summer and 150 in the winter. I have a 2HP, three-stage shallow well pump that produces 100PSI, and a 6 showerhead, 2 person shower. So I use a lot of water.
I've got it sitting at 135 now, which I find to be just about right. It has been keeping up with everything we've asked of it even with back-to-back showers. From the looks of what the app is telling me, we are averaging right around 4kWh in usage a day. From looking at my data just before we made the switch, I estimated that just me taking a shower, with nothing else in the house running was requiring about 4kWh just in itself. So just a back-of-the-envelope estimate, we look to be using anywhere from 1/4 to 1/3rd the energy we were with just the regular 2006 Resistive heater. That and it keeps my garage a little bit cooler, although the weather down here hasn't been all that hot. I have it locked into heat-pump mode, so the elements don't run, ever.

I do plan on making one change to it though. I'm working on drawing up a 3d printed duct for the intake and then running an 8" duct up to the top of the space it sits in so that the intake air is drawn from the ceiling of the garage. I don't have a picture of it, but there is a 12" overhang that comes down into the water heater space. I should be able to punch an 8" hole through it and put a grill on it so that intake air is further separated from the exhaust. (I know they make a pre-made duct for this, but it is $150, I'm not paying that for a piece of injection-molded plastic.)

You can just see it towards the left in this picture, it creates a little space near the top of the area:

IMG_20220410_140239519.jpg


Screenshot_20220416-212937.png
 
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Consider bumping the temp to over 140. Even if it's just once in a while. Bacteria can grow in water under 140. Also, it helps with the amount of available hot water.

I removed a propane water heater.
I now have a first generation AO-Smith 80 gal hybrid water heater. It air conditions my South Florida 3 car garage! I think I installed it about 2011. It's been excellent, and I was able to remove the 12,000 btu window AC in my garage. Not only did I eliminate a $5.50 per gallon propane bill, but my electric bill went down, as I was no longer running the window AC 24/7.

I do run the temp at 140 in the summer and 150 in the winter. I have a 2HP, three-stage shallow well pump that produces 100PSI, and a 6 showerhead, 2 person shower. So I use a lot of water.

Mine consumes about 650 watts when running. I do not use the resistance heating elements.
State sanitary code here has 130 as the limit and I guess even at 135, it might drop down to 130 at the tap. You just need 140 to kill legionnaire's disease so I guess OP can bump it up to 140 once in a while.
 

ctechbob

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State sanitary code here has 130 as the limit and I guess even at 135, it might drop down to 130 at the tap. You just need 140 to kill legionnaire's disease so I guess OP can bump it up to 140 once in a while.
Yea, I can program it to run to 140 for a couple of hours every week.
 

ctechbob

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Just an update to this thread. So far, so good. I've done a few things, like insulate the hot side piping, and I designed and 3D printed a duct to go on top of the unit that I'm going to punch through to the attic directly above the heater (The 'Official' Rheem duct is $150, no thanks). The air up there is a lot warmer year round than it is in the garage, so that should give a nice little boost to the efficiency of the unit, not that it struggles in that department. Most days we are using less than 3kWh's of power, some days less than 2. For reference, a while back I was able to determine that I used around 4kWh just to take one shower, I still take at least one a day, as does the rest of the family (2).

I got my $500 check from the EMC yesterday, so the unit has officially cost me $568, not counting the install items, which most of I'd have had to buy to replace it with another resistive unit anyways, so I'm not counting those, but that was about another $150ish. (Pex connectors and tools, expansion tank, condensate pump, etc).

All-in-all, extremely happy with the results.

Screenshot_20220428-212100.jpg


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Just an update to this thread. So far, so good. I've done a few things, like insulate the hot side piping, and I designed and 3D printed a duct to go on top of the unit that I'm going to punch through to the attic directly above the heater (The 'Official' Rheem duct is $150, no thanks). The air up there is a lot warmer year round than it is in the garage, so that should give a nice little boost to the efficiency of the unit, not that it struggles in that department. Most days we are using less than 3kWh's of power, some days less than 2. For reference, a while back I was able to determine that I used around 4kWh just to take one shower, I still take at least one a day, as does the rest of the family (2).

I got my $500 check from the EMC yesterday, so the unit has officially cost me $568, not counting the install items, which most of I'd have had to buy to replace it with another resistive unit anyways, so I'm not counting those, but that was about another $150ish. (Pex connectors and tools, expansion tank, condensate pump, etc).

All-in-all, extremely happy with the results.

View attachment 98058

View attachment 98059 View attachment 98060 View attachment 98061
Is your goal trying to make your water heat up faster with less energy? or cool the house along the way (to reduce ac expense)? If later you probably want to use air duct (bypass AC in parallel) as the air source.
 

ctechbob

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Is your goal trying to make your water heat up faster with less energy? or cool the house along the way (to reduce ac expense)? If later you probably want to use air duct (bypass AC in parallel) as the air source.
Just to maximize the efficiency and as a 'why not' type thing. I get no bonus for cooling the house since it is in the garage, but if I can feed it hotter air, it will be more efficient. I originally started it as a way to make sure the intake and exhaust are separate since I'm in a slightly confined space. I was going to baffle the top from the bottom, but as I have the 3d printer, I thought why not do something a little more elegant.

I have the printer, and I have the knowledge, spend $10 on the flexible duct from Amazon and have at it.
 
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ctechbob

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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.

wh.jpg
 
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We installed a Rheem 55 gallon a little over a year ago. We have 3 teenaged boys who all love to shower until there is no more hot water. After I learned the programing, happy to say that the first year usage w $87.00 and other than in the beginning, we've never ran out of hot water. I live in FL in heater is in the garage. Its set on heat pump only during the mornings and evening's at 135 and off hours at 125. Could not be happier.

Tim
 
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2 years ago today. Heat pump only mode all the time 135f-145f its nearly free hot water as it is my basement dehumidification.

image_2022-08-27_093540673.png
 
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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.
 
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