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  1. #1
    Join Date
    Feb 2013
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    Question Water heater heat pump

    Can anyone further explain how the heat pump on the water heater works out? I'm feeling kind of dumb on this, but I don't quite understand how ambient heat can make hot water. On one hand, no one's house is 100+ degrees inside, and on the other hand, if I'm heating my house through the winter but then somehow cooling it with this device, aren't I losing the efficiency of something?

    I'm pretty interested in this technology, and admittedly, my furnace is in the same room as my water heater and does tend to make that room warmer than it needs to be. I believe it does work, but just want to understand.

    Also, the condensate that gets pumped out: is it clean? Instead of sending it down the drain, could it be sent to a pet water dish?

    Thanks in advance!

  2. #2
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    Default Re: Water heater heat pump

    There is a tremendous amount of information on this subject on the internet that you can read.

  3. #3
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    Aug 2007
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    Maryland
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    Default Re: Water heater heat pump

    Dj1 is correct about reading how heat pumps work.
    The condensate should be clean as long as it flows from the unit freely. I've heard of people using the condensate on plants. It seems like too much trouble to use for pets. Usually the condensate goes to a sump to be pumped out. I wouldn't drink it unless that was the only water I could find. I think my dog drinks more than the water heater could provide, but I don't know how much water they can provide.

  4. #4
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    May 2008
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    Default Re: Water heater heat pump

    The heat pump on the water heater works using the same principles as a heat pump used for home heating. Since they are able to extract heat from outside -- even when it's 40 degrees outside -- and heat air to above the ambient temperature inside the house, there's no reason a heat pump water heater can't do the same.

    As for efficiency, that's a tough call, because even though it's cooling your house, the additional heat your furnace needs to produce really isn't wasted... that extra heat goes into heating the water. And since the heat pump cycle is typically more efficient than the electric resistance heat that's the other option on the water heater, your total energy bill may still be lower when you run it in heat pump mode. But I am not an expert in that, so your experience may be different.

    Since mold can grow in the dust that collects on the condenser coils of the WH heat pump, I wouldn't use that water for human or animal consumption. However, it may be just fine for plants. The water is nearly mineral free (aside from anything that might wash out of the dust), so may be ideal for washing windows or other things that could be affected by the mineral content of tap water.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  5. #5
    Join Date
    Feb 2013
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    6

    Default Re: Water heater heat pump

    Quote Originally Posted by dj1 View Post
    There is a tremendous amount of information on this subject on the internet that you can read.
    Yeah, thanks. I've never heard of this "internet" thing you speak of. The thing is, I don't want a tremendous amount; I was rather hoping a knowledgeable and succinct person could give me, and others like me who watched the episode and didn't understand, a short answer on the message boards associated with the show on which I first heard of the technology. Let me help you complete your useless reply: http://lmgtfy.com/?q=how+do+heat+pumps+work

    Sheesh. Forget I asked.

  6. #6
    Join Date
    Jan 2014
    Posts
    1

    Default Re: Water heater heat pump

    Your refrigerator is a heat pump. It makes cold well below the temperature of the ambient air in your kitchen.

    It relies on the principle that when you compress gas it gets hot, and when gas is expanded, it gets cool.

    For the water heater, it is like this: A gas (freon, ammonia, other) starts at room temperature and is compressed making it very hot. Then that hot compressed gas is passed through a heat exchanger heating the water and cooling the gas. The (now cooler) compressed gas is fed into another heat exchanger, called a condenser, and allowed to expand. The expanding gas cools to well below room temperature. Room temperature air from the room is passed through the condenser warming the gas and cooling the air.

  7. #7
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
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    5,622

    Default Re: Water heater heat pump

    DuluthGirl, yes it works just like the refrigerator or the air conditioner. Because heat pumps are nearly 100% efficient it takes much less energy to heat the water than heating coils or a gas flame. Yes it does induce some cold air into the basement, how that balances out with the heating cycle I can not answer. At this point I do not know if it saves enough energy costs to be viable or if it is just a gimmick.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  8. #8
    Join Date
    Aug 2007
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    Maryland
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    Default Re: Water heater heat pump

    Quote Originally Posted by DuluthGirl View Post
    Yeah, thanks. I've never heard of this "internet" thing you speak of. The thing is, I don't want a tremendous amount; I was rather hoping a knowledgeable and succinct person could give me, and others like me who watched the episode and didn't understand, a short answer on the message boards associated with the show on which I first heard of the technology. Let me help you complete your useless reply: http://lmgtfy.com/?q=how+do+heat+pumps+work

    Sheesh. Forget I asked.
    Forgotten. Glad I didn't waste my time and put any more effort in it than you did.

  9. #9
    Join Date
    Feb 2013
    Posts
    6

    Red face Re: Water heater heat pump

    Cool Javelin! You are just the person I was hoping for. Perfect answer.

    Thanks also to JLMCDANIEL. I agree: gimmick or breakthrough device? It sounded great on the show.

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