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Heat Pump water Heaters

I'm tempted by the LG because I kind of want to try new hotness, and maybe help out others by sharing my experience. I probably don't need the <30F lockout here in San Mateo county, it might help me out 3 hours out of a whole year LOL.

If Demand Response is essential then this gets way more expensive than my local price for a boring old Rheem

I was thinking about AOSmith Voltex AL, but man there are some really pissed off people that have exchanged them a couple times already, and they outweigh everybody else on some review sites. Incidentally Voltex Max has a built-in mixing valve on their 240V. I don't see it sold anywhere yet. This looks cool... but then they have some vague literature about how it does the mixing in a smart way and I get kind of scared at a water company doing programming LOL.
 
Mixing valves are a problem when they stop working. I was thinking of a globe valve for a fixed mix.

Also look for one with a 24hr timer so it heats when the sun is shining.
 
DIYrich said:
Mixing valves are a problem when they stop working. I was thinking of a globe valve for a fixed mix.

Also look for one with a 24hr timer so it heats when the sun is shining.
Click to expand...
Mixing valves (and globe valves) are a problem at low flow, especially when very slow convection can put a slug of max-temp water into the pipes. When I tried one out, it would only release scalding water at low flows, which was worse than removing it and knowing how hot to expect the water to be.
 
time2roll said:
Our life seems even simpler. Considering just 40 gallons. Is this crazy? The closet is rather limited space.

Second question.... some of these seem to run on 120 volts. Any loss of efficiency vs 240v?
Mini-splits always seem to be higher SEER with 240v.

Pulling a new 240v circuit could be more difficult vs jumping off an existing. 400w seems easy. Mild climate should be heat pump only.
Click to expand...
I think we could make a 40-gallon work but might run oit on very rare occassions, so I don't think you're crazy. But only you can tell for certain about how much hot water you need.

As for the 120V versions, I think they would work fine in heat pump only mode but I would be very reluctant to try them in any other mode. Also, be careful about overloading the circuit if you tap off an existing one. Some codes/AHJs may require a dedicated circuit, but you'd need to check on that locally.
 
There are a few different brands that resell the same units and just slap their own label on them, just like dishwashers and fridges. AO Smith is one of those.

I got an AO Smith 50 gal a few years ago, and only run it in heat pump mode. 120* in the summer, 125* in the winter, just to offset the cold pipes. My need for hot water is low (live alone, staggered usage) and it's been great. Just installed an Anker whole-house backup and decided not to put the water heater on the backup circuits, even tho it only draws 600W. If I need to replenish the hot water, I can do it with a small 240vac inverter generator. I wouldn't chance using a "dirty power" generator on a heat pump.
 
time2roll said:
Our life seems even simpler. Considering just 40 gallons. Is this crazy? The closet is rather limited space.

Second question.... some of these seem to run on 120 volts. Any loss of efficiency vs 240v?
Mini-splits always seem to be higher SEER with 240v.

Pulling a new 240v circuit could be more difficult vs jumping off an existing. 400w seems easy. Mild climate should be heat pump only.
Click to expand...

Does the 240V unit require Neutral? If not, one can wrap the ends of the existing white Neutral wire with red tape at both ends, and run 240v through the wires that used to serve a 120V circuit, without a Neutral. Depending on the existing 120V circuit, you may be able to get 240v at 20A without rewiring the run.

EV drivers do this all the time, to cheaply get an EVSE running at 240V and up to 12A or 16A (depending on the circuit), to charge their cars. It's only at 12A or 16A, because of the NEC "80% Rule" on a 15A or 20A circuit. EVSEs rarely need a Neutral.
 
I have the wire and enjoy wiring and need a new wire to handle the amperage if I ever use the heater elements. I only wire with grounds and neutrals . I worked as a sparky so really I only know how to do it the right way. Sure plenty of Joe bob options but weather it calls for a two wire or three I only have the right wire anyway in in stock meaning 3 conductor and ground. My assumption since I have yet to open heater box is the electronics of the heat pump require a neutral at 240v -most likely a step down transformer to 110 v for that curcuit
 
I will be pulling 4 wire 240/120 as I am looking at a circulation pump also. Maybe some of those are 240 also idk.
 
I hope i can post a link to this pump without breaking any rules you can pick them up at many retailers-this one I use a lot and is trusted.
I have this memory of not allowing links to retailers -If that the case sorry and please remove link
pump is about 320$

Comfort 10-16 T BU/LC Hot Water Recirculating Temperature Pump​

This pump has been incredible -I learned about it long ago in Finehomebuilding-super smart and super low cost to run-it moves hot water very smart and knows when you go away. Variable infinite speed (dc if I recall). Been in service for about 8-10 years with zero issues.Recomend it highly
 
Last edited:
onokai said:
I hope i can post a link to this pump without breaking any rules you can pick them up at many retailers-this one I use a lot and is trusted.
I have this memory of not allowing links to retailers -If that the case sorry and please remove link
Click to expand...

If the link is not an affiliate link, meaning you get paid a percentage if someone clicks on the link and buys the product, then it is allowed. The same goes for videos linked here, no affiliate links.
 
onokai said:
Great I'm not affiated with anyone-thanks for the explanation
Click to expand...
I could monetize my Youtube channel and make money off affiliate links but I would not be able to share those videos here. I made the decision early on not to monetize my channel, I make my living off my real job and not my hobbies. This also allows me to present an honest opinion, I'm not financially tied to anyone. I only want to share the experience, help others and share information. I learn from others too, this is a way of spreading the wealth of knowledge.
 
OK now I am comparing RHEEM from HD and AO Smith from Lowes. Both 120 volt.

AO smith has 900 watt electric elements in addition to the heat pump. I think this is for low ambient temps and maybe for backup if the compressor fails. I like this. Virtually made to be heat pump only. Rated less than 10 amp draw as max.

RHEEM 120v seems to be heat pump only and works down to 37F and that should not be an issue even with my WH closet vented outside.

I really would like to get away from the high powered electric elements that require 240v. Any thoughts on these?

Rheem. Rheem oem website

AO Smith
 
Yes I believe the AOSMITH backup heat is sized to heat at close to the same slow speed as the HP.

There is also a Rheem 120V model with a 3x bigger compressor. It is specced for dedicated 120V circuits.

I haven’t had a chance to look at the LG inverter specs, it is a hybrid with supposedly a super quiet compressor

Personally I prefer the 240V hybrids because it hedges against outlier use cases where I might need more water, like having guests

You should only vent your WH outside if intake and exhaust are both connected to outside
 
time2roll said:
OK now I am comparing RHEEM from HD and AO Smith from Lowes. Both 120 volt.

AO smith has 900 watt electric elements in addition to the heat pump. I think this is for low ambient temps and maybe for backup if the compressor fails. I like this. Virtually made to be heat pump only. Rated less than 10 amp draw as max.

RHEEM 120v seems to be heat pump only and works down to 37F and that should not be an issue even with my WH closet vented outside.

I really would like to get away from the high powered electric elements that require 240v. Any thoughts on these?

Rheem. Rheem oem website

AO Smith
Click to expand...
I use the Rheem 240 volt and simply disconnected the heating elements to force a HP-only operation.
You might ask why since there’s a compressor only function in the app? Answer - it doesn’t work that way. I talked to Rheem and their understanding is there will circumstances that activate the elements even in compressor only mode.
If you disconnect the elements on a Rheem 240 volt, you will likely get an occasional error with the description “Element relay failure”. That’s all.

Overall I’ve been happy with the Rheem.
 
DVD said:
I use the Rheem 240 volt and simply disconnected the heating elements to force a HP-only operation.
You might ask why since there’s a compressor only function in the app? Answer - it doesn’t work that way. I talked to Rheem and their understanding is there will circumstances that activate the elements even in compressor only mode.
If you disconnect the elements on a Rheem 240 volt, you will likely get an occasional error with the description “Element relay failure”. That’s all.

Overall I’ve been happy with the Rheem.
Click to expand...
What are your personal reasons to HP only via buying and modding a 240V?

Did you also consider switching to lower wattage elements?
 
DVD said:
I use the Rheem 240 volt and simply disconnected the heating elements to force a HP-only operation.
You might ask why since there’s a compressor only function in the app? Answer - it doesn’t work that way. I talked to Rheem and their understanding is there will circumstances that activate the elements even in compressor only mode.
If you disconnect the elements on a Rheem 240 volt, you will likely get an occasional error with the description “Element relay failure”. That’s all.

Overall I’ve been happy with the Rheem.
Click to expand...

The only time that the Rheem will kick on the elements is when it is too cold to run the compressor, and that is somewhere under 25f. I've had the 'normal' 240v unit for 3 years now and only two days has it ever run the elements locked into HP mode.
 
zanydroid said:
What are your personal reasons to HP only via buying and modding a 240V?

Did you also consider switching to lower wattage elements?
Click to expand...

HP's are just a better use of power, especially in warm'ish climates where the HP is in the garage or out of the living space.

I see COP's well over 4 in the summer with mine.
 
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