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Tankless water heaters are terrible....

Discussion in 'Energy, Environment, and Policy' started by nwdiver, May 1, 2017.

  1. dhrivnak

    dhrivnak Active Member

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    The lights look like an older method not counting on being all LED. If your not all LED do so. Then all small appliances are not running at the same time and your not running the garage door when charging the cars. Driving the Model 3 for 3 years now we have found 24 amps works fine for over 99.9% of the time. So bottom line I think you would be fine with the 30 amp Rheam. Which by the way is likely my next water heater. And mine is now 21 years old.
     
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  2. mongo

    mongo Well-Known Member

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    I believe real world baselining is an option. Although that needs to be instrumented to catch peak vs average.
    Lighting loads are a big part of the Watts per square foot number.
    For circuits, they planned ahead for a plasma TV in every room :)
     
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  3. SageBrush

    SageBrush REJECT Fascism

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    If not 10
     
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  4. SageBrush

    SageBrush REJECT Fascism

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    Somewhat off-tangent, I was thinking about these threads from people with small panels and max current calcs that restrict their consumer choices. There may be a market opportunity here for a device that monitors total current and automatically turns off designated devices if threshholds are breached.

    Makes a lot more sense to me than one-size-fits-all calc sheets, and safer too.
     
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  5. Dave EV

    Dave EV Active Member

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    That's what I said the other day and pointed out two devices on the market that turn on/off your EVSE based on usage. One monitors your whole house usage (DCC-9 / DCC-10), The other monitors your dryer circuit (Dryer Buddy) (kinda buried near the bottom of a long post - sorry!)
     
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  6. SmartElectric

    SmartElectric Active Member

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    I recently calculated the option of a
    1. pool heat pump system + PV compared to
    2. solar pool water circulation heating panels

    More than 12 years ago I had #2 installed for $3K : our pool is >90F from June to Sept in "relatively cold climate" Ontario Canada, very little maintenance, operates when the sun shines and the pool circulation pump is running. The panels are black plastic, low maintenance, just drain before winter along with the pump other piping.

    Whereas a heat pump + additional PV array (more than double our current 3.5 kW would be needed) would be a big investment to add one month on each end of the swim season, and I realized we don't swim when it's cold outside anyway. You can just buy the heat pump to add a few months on each end and pay for grid electricity, but I wanted a pure solar solution, and heat pump needs many hours per day to heat, up to 9 hours in my case, so lots of panels would be needed, and a battery system to store some of the solar surplus to even out the load. Compared to the entirely reliable and cheap option #2, I don't see the point of electric heat pumps for pool heating for my climate.
     
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  7. JeremyWhaling

    JeremyWhaling Member

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    I did some more research and notice that my particular 40 gallon gas water heater has a fairly high recovery ratio (41 GPH) and first hour rating (71 GPH) for its size. The Rheem is 27 GPH and 60 GPH respectively. I am not sure this matters, but considering the overall size of the unit... it probably does.

    Gas seems to be better at recovery, even in tank form. I think this matters more in the smaller size tanks.
     
  8. rajkumarjoy26

    rajkumarjoy26 New Member

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    Thanks for explain
     
  9. nwdiver

    nwdiver Well-Known Member

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    Well... yeah... the purpose of the Rheem is to use ~2kWh to heat the water instead of ~8 not to heat the water quickly.
     
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  10. SageBrush

    SageBrush REJECT Fascism

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    In case Jeremy has the same trouble I did parsing your comment, I think you are saying

    Well... yeah... the purpose of the Rheem is to use ~2kWh to heat the water instead of ~8, not to heat the water quickly.

    And this all circles back to the advantages of a big tank where a heat pump is concerned.
     
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  11. nwdiver

    nwdiver Well-Known Member

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    • Like x 4
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  12. mspohr

    mspohr Well-Known Member

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  13. gene

    gene Supporting Member

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    #333 gene, Dec 12, 2020
    Last edited: Dec 12, 2020
    Maybe it has been mentioned earlier. Until the end of this year, if your utility is SCE, you can get the Rheem Hybrid water heater with $1,000 off at purchase from SCE and $300 back on your federal taxes as a credit. I did it, and I have the water heater installed. It is fantastic.

    I think with tax and all, the water heater was $1467, less $1000, less $300 is a net of $167. I did have to pay an electrician $300 in order to wire in a 240v 40 amp box next to the heater.

    This water heater makes some noise like a very small window AC unit. The byproduct is cold air so it nicely cools my garage which can get really hot in the summer. Outside or garage install is perfect. Inside your home you might not like the noise.
     
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  14. SSedan

    SSedan Active Member

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    Mine has been in use a few weeks now.

    I am going to have to set it to straight electric most of the winter.
    Expected as much, not a complaint and I will still be able to use it as intended probably 8 months of the year.

    My basement doesn't have sufficient excess heat this time of year in WI. Room this is in has baseboard electric that I generally don't turn on. Letting this chill the room too much causing me to turn on baseboard electric heat would be a poor decision.
    None of the airsource heat pump minisplits are near enough to supply this well.
     
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  15. Merrill

    Merrill Merrill

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    My water heater is inside next to my HVAC unit, wonder how much noise it makes.
     
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  16. ChadS

    ChadS Last tank of gas: March 2009

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    From the article: "Plan to speak to several plumbers in your area to identify those who have experience with HPWHs. Since they currently account for just 2 percent of the water heating market, HPWHs will be unfamiliar territory to many contractors, who may even try to steer you away from energy-efficient options simply because they are more familiar with standard heaters."

    That's a real concern. A couple of years ago I needed a new water heater, and wanted the most efficient one available...I did manage to find a place to BUY a heat pump unit. But after quite a bit of searching, I couldn't find any local places that said they installed them. So I just started calling plumbers...I think I called about 6. None of them would install one. Most of them just said they didn't install them and left it at that, but I think one went off on how they were unreliable, and another went off on how they didn't deliver the expected results. I hope things are changing...
     
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  17. mspohr

    mspohr Well-Known Member

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    I don't know about your DIY skills, but if you are replacing an electric water heater, it's dead simple to install a HPWH. Just fasten the water intake and output flexible couplings at the top and attach the wire. I've done this myself.
     
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  18. SSedan

    SSedan Active Member

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    The rheem/Richmond units have the plumbing on the side so there is rerouting.
     
  19. nwdiver

    nwdiver Well-Known Member

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    Don't forget condensate. Although I just collect mine in a bucket and it seems to evaporate faster than it fills :)

    Also if the HPWH has been horizontal for any reason don't energize it for 24 hours after going vertical... or so I've been told.
     
  20. iPlug

    iPlug Member

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    Anyone know if HPWHs are being successfully decommissioned like home central air conditioning units, specifically with regard to removing the refrigerant prior to disposal/recycling?

    Understandably HPWHs are a fairly nascent entrant, but the refrigerant will have to be properly evacuated at EOL to keep its GHG potential out of the atmosphere. Hopefully these things don’t just get straight away dumped in landfills.

    Some future day if/when CO2 refrigerant becomes fully developed, affordable and reliable at this scale such concerns will no longer matter.
     
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