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Thread: Electric tankless water heater

  1. #11
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    Wouldn't a heat-pump unit with a tank make more sense?

  2. #12
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    Quote Originally Posted by jaggedben View Post
    Wouldn't a heat-pump unit with a tank make more sense?
    It does to me. About 30% of normal run cost or thereabouts. A well-insulated tank has minimal loss.

    IMO, people get too happy about comparing old weak insulated tanks with instant units. Kind of like comparing new LED with old or low-efficiency fluorescent.
    BB+/BB=?

  3. #13
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    Quote Originally Posted by jaggedben View Post
    Wouldn't a heat-pump unit with a tank make more sense?
    It would depend on where the heat that was pumped went, and if it had to then be pumped again by air conditioning. Also it is physically much bigger.
    For me, I have a natural gas tank type that works fine. Came w/ the house 20 years ago. I don't know what the average life span for the heat pump units is.

  4. #14
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    It also amazes me when people constantly run out of hot water they blame it on their water heater. Simple concept is to run your tank type heater at 140-160 deg F then either install a tempering valve or just turn your faucets towards cold so the water is comfortable. That way you use much less hot water from the tank and it will last a lot longer. People think that they need to turn down the temperature to save money but that's wrong. Even at 160 the outside of the heater will be barely warm so standby losses are minimal and the burner or heating elements will actually need to come on less because you aren't emptying the thing every time you take a shower.

    Personally I can see no advantage to tankless. They are expensive to install, require maintenance and, especially electric are expensive to operate. I also don't know their life span, replacement is expensive as well. With tank type heaters the rule is 7 years (though many last much longer than that) and they are inexpensive to replace.

    -Hal
    Last edited by hbiss; 06-15-19 at 01:31 PM.

  5. #15
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    Quote Originally Posted by Barbqranch View Post
    It would depend on where the heat that was pumped went,...
    In a heat pump water heater, the heat goes into the water.

  6. #16
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    Quote Originally Posted by jaggedben View Post
    In a heat pump water heater, the heat goes into the water.
    OK! "It depends on where the heat comes from".
    In particular you do not want to draw heat from environmental spaces that you have to pay to heat in the first place.

  7. #17
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    Quote Originally Posted by hbiss View Post
    It also amazes me when people constantly run out of hot water they blame it on their water heater. Simple concept is to run your tank type heater at 140-160 deg F then either install a tempering valve or just turn your faucets towards cold so the water is comfortable. That way you use much less hot water from the tank and it will last a lot longer. People think that they need to turn down the temperature to save money but that's wrong. Even at 160 the outside of the heater will be barely warm so standby losses are minimal and the burner or heating elements will actually need to come on less because you aren't emptying the thing every time you take a shower.

    Personally I can see no advantage to tankless. They are expensive to install, require maintenance and, especially electric are expensive to operate. I also don't know their life span, replacement is expensive as well. With tank type heaters the rule is 7 years (though many last much longer than that) and they are inexpensive to replace.

    -Hal
    +1

  8. #18
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    Quote Originally Posted by jaggedben View Post
    In a heat pump water heater, the heat goes into the water.
    LOL
    BB+/BB=?

  9. #19
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    Quote Originally Posted by Barbqranch View Post
    It would depend on where the heat that was pumped went, and if it had to then be pumped again by air conditioning. Also it is physically much bigger.
    For me, I have a natural gas tank type that works fine. Came w/ the house 20 years ago. I don't know what the average life span for the heat pump units is.
    As mentioned the heat is supposed to be pumped into the water.

    Quote Originally Posted by GoldDigger View Post
    OK! "It depends on where the heat comes from".
    In particular you do not want to draw heat from environmental spaces that you have to pay to heat in the first place.
    That is something to consider. During cooling season, you are lessening the cooling load on the general environmental space, during heating season you are adding load to it. If you have longer cooling season than heating season it may be more worthwhile than the other way around. If you have all electric heating/cooling system - might not matter all that much but can depend if you have seasonal changes in energy rates, or other special rate structures that may or may not be advantageous.
    I live for today, I'm just a day behind.

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