electric water likely the #1 power user in my house

jkhawaiijkhawaii Solar Expert Posts: 30
its seems that a regular electric hot water heater consumes upwards of 10kwh's a day, So, half of my homes average usage of 20kwh's go to a 95% idle water heater! one of those Heat pump water heaters seem like a good investment now, it would be Equal installing a, maybe, 2kw PV system in electric savings.
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Comments

  • icarusicarus Solar Expert Posts: 5,238 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Heat pump hot water, ro direct solar hot water, with possibly a demand gas (propane?) unit to supplement you solar or heqt pump. if you have enough sun for PV, hot weather is much more bang for the buck.

    Tony
  • BB.BB. Super Moderators, Administrators Posts: 29,497 admin
    Re: electric water likely the #1 power user in my house

    Some reading:

    Solar hot water
    (thread)
    www.arttec.net/SolarDHW/index.htm (project)
    www.solarroofs.com (vendor used by a poster here and few years ago and very happy)
    http://www.builditsolar.com/ (good DIY site)

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: electric water likely the #1 power user in my house
    jkhawaii wrote: »
    its seems that a regular electric hot water heater consumes upwards of 10kwh's a day, So, half of my homes average usage of 20kwh's go to a 95% idle water heater! one of those Heat pump water heaters seem like a good investment now, it would be Equal installing a, maybe, 2kw PV system in electric savings.

    WOW! If it's costing you that much power just to keep your electric water heater "idling" all day, then definitely it needs additional insulation! Years ago when I had only electric hot water and was working away, I added at least a foot of fiberglass insulation over and around my 30 gal tank, and it would stay hot for a week while turned off. I'd shut it off Sunday night, head out to work early Monday morning, and when I got home Friday night, there would still be enough hot water for a shower.
  • SteveKSteveK Solar Expert Posts: 277 ✭✭✭✭✭✭
    Re: electric water likely the #1 power user in my house

    We, a family of 3 full-time adults and one part-time, use a HPWH and it costs us ~4.5KWH per day. An excellent investment in my opinion.
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: electric water likely the #1 power user in my house
    WOW! If it's costing you that much power just to keep your electric water heater "idling" all day, then definitely it needs additional insulation! Years ago when I had only electric hot water and was working away, I added at least a foot of fiberglass insulation over and around my 30 gal tank, and it would stay hot for a week while turned off. I'd shut it off Sunday night, head out to work early Monday morning, and when I got home Friday night, there would still be enough hot water for a shower.
    My previous 40 gal electric waterheater used about 6 kwh per day. My new ge geo spring uses averaged 1.34 kwh per day for 1st year for 1 person. Good long shower everyday with runnibg dishwasher 3 times week and cloths washer 3 times week. I am very satisfied with my geo spring. 490 kwh for whole year with utility meter dedicated to the waterheater usage. :Dsolarvic:D
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Directly solar heating water has gotten a lot cheaper over the years. I am pretty sure its at least cost competive with electric and propane, not nessaraly competive with cheap natural gas.
    One thing solar is good for is heating. Most of the wave lengths in sun light are useless for PV, but nearly all wave lenghts can be used for heating.

    Using PV to heat water just seems like a huge waste of money.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • jkhawaiijkhawaii Solar Expert Posts: 30
    Re: electric water likely the #1 power user in my house

    Yeah, I just realized how much a electric water heater uses every day. I know my Coworker has a 8 panel PV system but has a standard electric water heater, so all that power his solar panels are producing are just powering the water heater haha. this water heater would be the lowest cost Attachment not found.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    "Most of the wave lengths in sun light are useless for PV, but nearly all wavelengths can be used for heating."

    i have to correct you here on this as this is not true. pv does respond to all light frequencies even into uv and infra red to various degrees. the problem with pv is not the response to wavelengths, but rather its overall efficiency. pv efficiencies are typically only in the teens whereas solar thermal is closer to the 50% mark if i remember rightly. solar thermal does not respond into uv area as most of the energy is collected near the infra red region so in terms of wavelength response goes solar thermal is worse. in terms of efficiency solar thermal wins hands down as it collects more useful energy.
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: electric water likely the #1 power user in my house

    I would add more insulation and put it on a timer. Have mine set to turn on about a hour before I need it.
  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: electric water likely the #1 power user in my house

    Heat pump assisted hot water heaters in heat pump mode is not fast recovery. Take this into consideration if you have four folks taking showers in a short period of time.

    Operating solely from heat pump, they comsume about 500 watts of electric and produce the equivalent of a 1000 watt conventional heating element. Most purely electric heating elements hot water heater use 3500 to 4500 watt electric resistive heating elements so the recovery time is 4 times longer running solely on heat pump. They normally go to high power resistive element assist if water temp drops too much due to high demand, which puts you back to old way of heating water electrically.

    If you get one, go with larger gallon size to get more reserve. If you had a 40 gallon resistive unit, go with a 50 gallon heat pump assist unit.
  • oil pan 4oil pan 4 Solar Expert Posts: 766 ✭✭✭✭
    Re: electric water likely the #1 power user in my house
    RCinFLA wrote: »
    Heat pump assisted hot water heaters in heat pump mode is not fast recovery. Take this into consideration if you have four folks taking showers in a short period of time.

    Operating solely from heat pump, they comsume about 500 watts of electric and produce the equivalent of a 1000 watt conventional heating element. Most purely electric heating elements hot water heater use 3500 to 4500 watt electric resistive heating elements so the recovery time is 4 times longer running solely on heat pump. They normally go to high power resistive element assist if water temp drops too much due to high demand, which puts you back to old way of heating water electrically.

    If you get one, go with larger gallon size to get more reserve. If you had a 40 gallon resistive unit, go with a 50 gallon heat pump assist unit.

    How much does that cost?
    Sounds expensive.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.

  • BB.BB. Super Moderators, Administrators Posts: 29,497 admin
    Re: electric water likely the #1 power user in my house

    Sears is selling a 50 gallon GE heat pump water heater for ~$1,000. The list price appears to be $1,400.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Bill, Why I think the price is lowered so much is they are selling out the Chinese made geospring waterheaters. They started to build them in the usa in Kentucky on February 20 and will be lots cheaper than the China made ones. They have red tops on them instead of blue and looks like they took the plastic cover off where the regular heating elements are. I have one of the china made ones and am wondering if the american made ones are just as good. :Dsolarvic:D Oil pan. The geospring has regular heating elements in it same as a regular waterheater. It has different settings. You can set it to run heatpump mode only and it is the most efficient mode. and recovers 9 GPM. For someone that uses more water thier is a fast recovery mode that heats water with the heating elements part way and then goes to heatpump mode. There is a heating element only mode in case your heatpump breaks down you can still have hot water till you get heatpump repaired. I always had mine set on heatpump mode only and have never run out of hot water.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: electric water likely the #1 power user in my house
    BB. wrote: »
    Sears is selling a 50 gallon GE heat pump water heater for ~$1,000. The list price appears to be $1,400.

    -Bill

    Excellent info provided by that link BB. Thanks a lot for sharing this!
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: electric water likely the #1 power user in my house

    Ditto what n3qik said. Just adding 6" of insulation all around dropped my daily useage a noticable amount. Don't remember exactly how much. Then putting it on a timer so it stays off 18 hours of the day (on 2 hours in the morning and 4 at night) dropped it another 5%.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • peakbaggerpeakbagger Solar Expert Posts: 341 ✭✭✭
    Re: electric water likely the #1 power user in my house

    I frequently see hot water heater installations where the piping goes straight up to the ceiling and into the hot water system. It may look neat but its setting up a thermosyphoning loop where hot water from the tank rises up, then radiates heat to the air and then the cold water drops back down to the tank. Its a subtle process but over the long run, you are bascially heating the utility area with electric heat. Some folks use "heat traps" in the lines which are supposed to keep it from happening. I normally pipe in a loop just outside of the tank where the pipe come out of the top of the tank then elbows 90 degrees to horizontal, then another elbow so the pipe points vertically downward and then turn back up. Usually this solve the thermosyphoning issues.
  • sub3marathonmansub3marathonman Solar Expert Posts: 300 ✭✭✭
    Re: electric water likely the #1 power user in my house
    solarvic wrote: »
    Bill, Why I think the price is lowered so much is they are selling out the Chinese made geospring waterheaters. They started to build them in the usa in Kentucky on February 20 and will be lots cheaper than the China made ones.

    I am wondering, even if they will be lower priced than the Chinese made ones, will they be lower priced than the sale price the Chinese ones are at now?

    Is there any benefit or improvement to the ones made in Kentucky?

    Also, has the 30% federal tax credit for these water heaters expired or been extended or rumored to be extended at some point?
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Aparently they are lower priced. Why they are trying to dump the chinese ones. https://www.gewaterheater.com/GEStore/Appliances/BuyOnline/ModelSelection?Category=GeoSpring+Water+Heaters The ge store is selling them already. Sounds like they are going to be quieter, cheaper and provide some American jobs. I already see some fearures I like better than the one I have. :Dsolarvic:D
  • sub3marathonmansub3marathonman Solar Expert Posts: 300 ✭✭✭
    Re: electric water likely the #1 power user in my house
    solarvic wrote: »
    Aparently they are lower priced. Why they are trying to dump the chinese ones. https://www.gewaterheater.com/GEStore/Appliances/BuyOnline/ModelSelection?Category=GeoSpring+Water+Heaters The ge store is selling them already.

    Apparently solarvic is worthy enough to get into the ge store. They wouldn't let me in without an invitation.

    I was just about ready to get the Chinese one, but I read several reports that the coolant lines are thin and broke after about 18 months or so.
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Try this address https://www.gewaterheater.com/GEStore/Appliances/BuyOnline/Home
    Apparently solarvic is worthy enough to get into the ge store. They wouldn't let me in without an invitation.

    I was just about ready to get the Chinese one, but I read several reports that the coolant lines are thin and broke after about 18 months or so.
  • silvertopsilvertop Solar Expert Posts: 155 ✭✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Well now I see that there is also a HP that can be added to any water heater, Its called Air Tap seems to have good reviews. They say it uses 660 Watts 110v, maybe this might be the way to go? GE has some neg. reviews, same with Geo Spring.....660 Watts could run with my solar on a timer.
  • icarusicarus Solar Expert Posts: 5,238 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Remember, that (with the exception of heqt pump technology) adding heat to water is a direct linear relationship between BTUs (KWHs) transfed into the water. A lower wattage water heater wil just heat any given quantity of water slower. The same with a gas fired water heater. After you get Ned 100% efficient ( and some demand units are now in the 96% range) lowering the BTU capacity of the burner only serves to slow down the rate of rise.

    Tony
  • BB.BB. Super Moderators, Administrators Posts: 29,497 admin
    Re: electric water likely the #1 power user in my house

    AirTap is a heat pump based unit (quick look).

    Anyway, there was a thread here last year with a little bit of discussion:

    Airtap
    - any users here?


    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • sub3marathonmansub3marathonman Solar Expert Posts: 300 ✭✭✭
    Re: electric water likely the #1 power user in my house
    solarvic wrote: »

    Well, it still wants you to register. Which I would do, but it also wants your "Authorization Code as shown in email or flyer."

    So apparently I'm still not worthy.
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    Here is the website that I found before. http://www.geappliances.com/heat-pump-hot-water-heater/ Hope this will get you to a place you can learn more about it. And I got to store from here. I can,t seem to get on thier site by using that address even though it let me do it after I posted the address. Way I got on it was I did a search about geospring waterheaters built in USA. read the story and clicked on where to buy. It put me right on the store.
    Probably don,t have the supply chain filled yet and when you get on the GE store it says backordered till April. At least if you do the search you can find some of the differences from the Chinese ones. Solarvic
  • solar_davesolar_dave Solar Expert Posts: 2,343 ✭✭✭✭
    Re: electric water likely the #1 power user in my house
    Well, it still wants you to register. Which I would do, but it also wants your "Authorization Code as shown in email or flyer."

    So apparently I'm still not worthy.

    Try this RSUPEXTWP
  • sub3marathonmansub3marathonman Solar Expert Posts: 300 ✭✭✭
    Re: electric water likely the #1 power user in my house
    solar_dave wrote: »
    Try this RSUPEXTWP

    YES!!! It worked. I feel so ... worthy.
  • sub3marathonmansub3marathonman Solar Expert Posts: 300 ✭✭✭
    Re: electric water likely the #1 power user in my house
    solarvic wrote: »
    Probably don,t have the supply chain filled yet and when you get on the GE store it says backordered till April. At least if you do the search you can find some of the differences from the Chinese ones. Solarvic

    If the new American one costs $175 more than the Chinese one, which one would people get? Is the American one that much better?

    Also, does it make a difference that the Chinese one has been sitting as a display for about a year?
  • solarvicsolarvic Solar Expert Posts: 1,053 ✭✭✭✭
    Re: electric water likely the #1 power user in my house

    submarithonman. The american geospring is way cheaper than the Chinese made waterheater. Don,t see where you got the idea that the American one cost more. One of the problems with the chinese one is the pressure relief valve is in the back of the waterheater. Chinese one has 2 fans and the american one has the pressure relief valve in the front of waterheater and 1 larger fan that is suposed to be quieter. I wouldn,t see why the waterheater bieing in the store for a year would make any difference. Warranty starts when you buy it. Looks like they also didn,t put the plastic cover over the waterheater elements on the american one either. So far I have had my chinese geospring 1 1/2 years with no troubles yet. If you see a chinese one cheaper it is because they want to clear out the old models. :Dsolarvic:D
  • sub3marathonmansub3marathonman Solar Expert Posts: 300 ✭✭✭
    Re: electric water likely the #1 power user in my house
    solarvic wrote: »
    The american geospring is way cheaper than the Chinese made waterheater. Don,t see where you got the idea that the American one cost more. :Dsolarvic:D

    Thanks solarvic!

    This is an unusual situation because the Chinese made waterheater was a display model and therefore discounted greatly.

    I also wonder if a house with an 80 gal waterheater set at 110°F will be OK with a 50 gal waterheater set higher. I'll have to try to calculate what setting it needs in order to store the same amount of heat. The problem then of course is the potential of too hot water in the house.

    The calculations are:
    An 80 gallon waterheater has about 9.4kwh of stored heat at 110°F. In order to obtain roughly the same stored heat, a 60 gallon waterheater is needed to be set at 125°F to have 9.2kw. But, now that the smaller waterheater is set at a higher temperature, it will be losing more heat through thermal loss to the outside. I am estimating based on rough calculations that this could be 0.5kwh / day. So now, part of the gain of the hybrid has been lost. I am guessing 80 gallons of hot water usage / day. So it takes the 9.4kwh to heat a full 80 gallon tank / day. Now, if the hybrid is twice as efficient, it is down to 4.7kwh / day for the hybrid, but losing another 0.5kw/day ends up at 5.2kwh/day. So about 10% of your savings is lost if you have to keep the smaller water heater at a higher temperature. But now thinking too, you'd only use about 90% of the hot water, so you would probably save the extra 0.5kwh of thermal loss with less water being heated.

    I was also wondering how much electricity (amperage) the waterheater used when heating in eco-mode.

    Here is something else that seems a bit interesting. You could pay $900 to get the 4.7kwh/day electric savings from the hybrid waterheater, or if spent on solar panels it would give about 4.5kwh/day electric generation (at $1/watt PV, 5 hr/day sun). So the calculations are more complicated than just jumping into a hybrid waterheater. Of course, if you're needing to replace a waterheater anyway the calculations go back to favoring the hybrid more.
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