water heater elements

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by wondering, Jul 5, 2007.

  1. wondering

    wondering Member

    Messages:
    106
    I read somewhere that there is a difference in electric water heater elements. There are "standard" ones and then there are some that are"low watt density". From what I read the "low watt density" are supposed to be more energy efficient? Is this true? Also, do you know anything about an element called a "sandhog" or something like that. It is a very curvy element that is supposed to last for years?
    Also, do you think that you save energy by having the thermostat on 120 versus 140? I feel like at 120 we use more hot water showering than we would at 140 plus the dishwasher runs a long time at 120 heating the water.
    Appreciate any thoughts/advice you have on this.
  2. got_nailed

    got_nailed DIY Senior Member

    Messages:
    277
    I have not heard of a sand dog element. But with hard water you can put in a stainless element that will not burn out. Most of the times the lower element will burn out because of build up that forms in the bottom of the tank. This is why some people will drain off part of the tank every few months to try and flush it out. Where I live (very hard water) I say it should be a monthly thing.

    As far as energy savings to heat water it will cost the same no matter what wattage or type of element you use. You use the same amount of watts to do the same amount of work. But if there is a build up of deposits or a bad dip tube it will take longer to heat the water so it will cost more. The water temp is up to you. With kids I would go with the lower setting.

    As far as the water temp IMO the cost in hot water is to heat the water. Once it is hot and no water is being used I don’t think it makes a difference on the energy bill to keep it hot (this is based on the newer heaters; but not in a cold unheated room). If you don’t keep up with flushing the tank then you will run into more problems in down the road.

    Depending on how old it was and if you can get most of the build up out of the heater I would replace the upper and lower thermostats and elements. I would not get any high $$ top of the line “sandhog” or stainless elements.

    I’ll try to find a post on flushing the heater and edit it in for you.


    edit
    This post has some good info on the build up and how to clean them out.
    http://www.terrylove.com/forums/showthread.php?t=13560&highlight=heater
  3. GrumpyPlumber

    GrumpyPlumber Licensed Grump

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    At 3:am your paying for hot water to sit in a tank.
    You can have it heated to 120, or 140.
    140 takes more energy, on the other hand does 120 give you enough to take all the showers your family needs?
    The dishwasher will heat the water, if it takes longer it's making up the time it would have taken your tank to heat...6 of one, half dozen of the other.
    It all boils down to "3:am".
  4. Cass

    Cass Plumber

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    5,980
    Location:
    Ohio
    Where I live the time zone changes about 50 miles due west of me so will that make any difference in your 3 AM scenario?
  5. GrumpyPlumber

    GrumpyPlumber Licensed Grump

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    Yes, by 3.2476 degree's minus the tangent of the obtuse perpendicular angle.
  6. hj

    hj Moderator & Master Plumber Staff Member

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    27,292
    Location:
    Cave Creek, Arizona
    elements

    Sandhog elements are stainless steel nichrome so they can operate without being immersed in water without burning out. They are my choice for replacing lower elements. High watt density elements are a single loop so they operate at a higher temperature, which causes more sedimentation to form on them, which gives them a shorter life.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,348
    Location:
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    Standby losses increase as the difference in temperature in the tank verses the area around it increases. This is minimized by good insulation. You'll get more hot showers out of a tank heated hotter since you'll use less of the hot by mixing with more cold water. The total amount of energy to heat it in the first place will be the same, making the only difference the energy to reheat it more often from standby losses. This is one reason I like indirectly heated tanks - the better ones can have as little as 1/4-degree per hour of standby losses. A good electric may approach that, while a gas heater can't because of the uninsulated flue and burner area.
  8. GrumpyPlumber

    GrumpyPlumber Licensed Grump

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    Jim, I recently I tried an experiment with a homeowner while switching out a boiler.
    He wanted to see how long his indirect would hold water hot enough for a shower...we waited till the day before inspection so I could disconnect the old boiler, reconnect the new.
    45 gallon Superstor ultra, after over 14 hours still had plenty for 2 normal length showers with no noticeable difference.
    The larger the volume, the less sq area for heat loss...wonder how long a 60 holds...
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,348
    Location:
    New England
    I've got a 70-gallon super stor ultra. My boiler seems to run only after using hot water...i.e., once a day or so. Washing hands, etc. don't draw enough water to trigger it on.
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