My experience with hybrid water heaters and a warning to stay away from AO Smith hybrid water heaters

[TOU47]

Since my system I am planning should have excess energy from PV, I’m just thinking of getting a large (80 gal) electric water heater and have it set to heat when there is excess power being generated during the day. With the large tank, I shouldn‘t need to heat it when the sun ain’t shining. Or at least rarely.

Exactly... solar dumping on a timer with it piped to my radiant heat would be ideal.

 

[TOU47]

I do HVAC for a living. I repair heat pumps all the time. Guess which one I bought? $2K more in solar panels. I'm keeping my 80 gallon and 5000W resistive elements. I have a timer that turns the water heater on at noon and off at 6 PM. Add 4 inches of insulation to the water heater and you'll have hot water all day/night long as long as you're not taking 30 minute showers or more than three people in the house. Less repair cost, less up front cost and we won't be cooling our basement or crawlspace down in the winter time.

YES...THIS! Could you please share details on this? Thoughts on also piping it in to the radiant heat with a boiler? Or maybe just doing it up to handle domestic hot water? Thx in advance!

 

[Rocksnsalt]

I do HVAC for a living. I repair heat pumps all the time. Guess which one I bought? $2K more in solar panels. I'm keeping my 80 gallon and 5000W resistive elements. I have a timer that turns the water heater on at noon and off at 6 PM. Add 4 inches of insulation to the water heater and you'll have hot water all day/night long as long as you're not taking 30 minute showers or more than three people in the house. Less repair cost, less up front cost and we won't be cooling our basement or crawlspace down in the winter time.

Thank you for posting this. You as an HVAC tech have confirmed why I don’t ever think I’ll buy a heat pump H2O heater.

First time I saw a heat pump water heater online, my thoughts after thinking “ oh nice, that’ll use less energy“ were:
1) more to go wrong
2) what a complex solution for a simple task
3) I prefer comparative silence

 

[beastman]

Thank you for posting this. You as an HVAC tech have confirmed why I don’t ever think I’ll buy a hp H2O heater.

First time I saw a heat pump water heater online my thoughts after thinking “ oh nice, that’ll use less energy“ were:
1) more to go wrong
2) what a complex solution for a simple task
3) I prefer comparative silence

They can be had cheap; the AO smith's are about 3.4x more efficient than even LP. ROI is about 2-3 yrs. I found one for $500 from a company that specializes in open box buys from lowes, etc. 66 gallons. Will be doing solar on the pre-heat tank (40 gallons) that feeds it w/ 2500w or so using a batteryless inverter. Don't want to mess w/ the directDC stuff; issues w/contactors, etc and high voltage. Household of 8 and we need more than what the 66 gallons can supply in a morning sometimes.

 

[Ampster]

I have actually had good luck with Rheem HPWH. Nine years ago I installed a GE GeoSpring HPWH and it only lasted five years before the compressor gave out..I had already put a Rheem in another house and in my sister's place, so I replaced it with a Rheem. GE sold the water heater division to Bradford-White and they were supposed to take over warranty work but I got runaround. A friend installed a AOSmith and has had good luck. In my area in Northern California AO Smith were more expensive than Rheem.
I am a firm believer that the optimum use of money is in energy conservation and a HPWH is 4 times more efficient than a resistive element. Plus the remote programming allow
s me to save money by running when energy is less expensive or turn it off when on vacation. Life is complex so I don't mind another device if it has a good payback.

 

[beastman]

I have family in the plumbing business for 50 years, manufacturer's reps for AOsmith in Northern CA. If there is a problem i can get it addressed.

 

[skew]

I cant speak of the new ones on the market. Ours is a 50 gal HPWH GE from 2008 one of the first ones out GE had a trial test and I was at the right place at the right time. I think the test units were built in Louisville and the production models ended up being made in China. We have not had the first issue still going strong and only uses around 400 watts. I would not go back to a normal waterheater. I have read the next generation HPWH will run on 120v hopefully ours will make it till then.

 

[pvdude]

I went with the "buy more pv" option.
Put the ancient, 17 year old electric water heater on the solar power.
Timer runs it once each day, around noon.
So far, working great!

 

[Ampster]

I went with the "buy more pv" option.

That can be the best choice if your cost of more panels is reasonable. I do have access to some used panels at very little cost but now need to find space for racking. I also need to use micros so that adds to the cost. Adding panels may take me over the 1kW which I am alllowed but if I rund the HPWH from 11AM until 3PM my Net Peak generaton will not exceed the value PG&E has for the capacity of my system.

 

[beastman]

That can be the best choice if your cost of more panels is reasonable. I do have access to some used panels at very little cost but now need to find space for racking. I also need to use micros so that adds to the cost. Adding panels may take me over the 1kW which I am alllowed but if I rund the HPWH from 11AM until 3PM my Net Peak generaton will not exceed the value PG&E has for the capacity of my system.

I'm in the same boat on nem 2.0 w/ PGE. You can offload pv direct and it won't go against your system, that includes the hot water heating. Doing two 2 ton EG4 a/c heat pump systems w/ 5k solar pv direct and pv direct and heat pump hot water system.

 

[efficientPV]

I have a very old Nyletherm unit which is an external HP and bought one for a friend as a divorce present. Thet were only $350 shipped, but only had a COP of around 2 like they all had at that time. Mine and his are still both running. He replaced his with a NYLE e8 unit #4 off the assembly line. They asked him to ship his old one back. They couldn't believe it was still running. I supplement mine with resistance from 500W of test panels. At camp it is all pure resistance heating whenever there is excess for my 3 water heaters. That setup is super efficient and cost next to nothing. The expense to up sizing my equipment to even run a HPWH just can't be justified. I know some people seem to wash elephants, but my needs aren't that high. The excess power is pretty reliable so we can have 60C water for the dishwasher and hot water for all cycles of clothes washer. Doing things right has advantages over easy.