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Heat your water with a heat pump - 50% electric savings!

Post in 'The Green Room' started by mikeathens, Jan 22, 2009.

  1. mikeathens

    mikeathens New Member

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    I know, my topic sounds like some cheezy scam ad in the back of better homes and gardens....

    I lost my on-demand propane water heater when we had a bad downdraft during sub-zero weather last week. It froze and then blew out the heat exchanger and left a nice pool of water in my house. I went to Lowes and grabbed a 50-gallon electric tank instaed of pissing around with the on-demand - it solved my downdraft problem and gives me STEADY hot water vs. fluctuating hot/cold, which is not nice for showering. I was shocked at the energyguide saying 4777 kWh/year avg. use. That's about what my 4 kW solar array produces in a year.

    I did some research and found this: http://www.airgenerate.com/products/airtap.html

    This thing mounts on top of your water tank and uses the refrigeration cycle to heat your water instead of resistance heating. You plug it into a 110 v outlet and switch off the breaker for the in-tank heaters. For us wood burners, this makes perfect sense! If you are heating with gas/electric/etc., might not be such a great deal since you're robbing your air of some of its heat (that you already paid for once). As a bonus, in the summer, it doubles as a small air conditioner/dehumidifier, so you're basically using the heat that your AC would normally throw outside to heat your water.

    To save on electric, you all might want to look into this. It costs $699 (I found a site with free shipping) and then there's a $300 tax credit for '09 taxes.

    No, I don't work for this place. I just think it's a great idea. I'm getting one, and planning to install a kill-a-watt meter on it to see what I'm actually using for hot water. I'd be more than happy to share my results when it happens.

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  2. jdemaris

    jdemaris New Member

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    Sounds like you only make a litte more watt-hours per watt of solar panel than I do here in central New York. I'm surprised considering I live in a pretty dark,snowy and rainly area. I've got a 5250 watt solar array and made, on average, 458 KWH per month last year. I.e., the 5250 watt array made 5500 KWH in a year. We use, on average, around 300 KWH per month - but we no longer use an electric hot water heater or clothes dryer. My biggest winter power draw is the electric blower on my wood furnace that runs, just about, all winter.
  3. mikeathens

    mikeathens New Member

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    The array was installed last April, so it hasn't QUITE been a year...but so far, if I remember correctly, the last reading I took (last saturday) was around 4500 kWh. I suppose if it clears up and we have some really sunny skies in Feb and March, I could see another 1000 kWh on that. GOOD sunny days will give us 20-22 kWh/day.

    EDIT: Oh, yeah, I forgot...we use about 600 kWh/month, of which a HUGE percentage is from running the aerator on our home sewage system, and the ultimate hog: our 1/3 hp myers jet (well) pump. I always forget that most people don't have these two things, which is why they are at 300 or less kWh/month.
  4. jdemaris

    jdemaris New Member

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    Well, no electric on our septic system at home, thank God. Just a gravity feed to a 1000 gallon tank and 300 gallon dry-well. But, if I ever install a septic system on my property in the Adirondacks, an electric pump system might be required. For now, we have a good old fashioned outhouse and an artesian well with a hand pump for water.

    I had a 3/4 horse jet-pump here for years, hooked to a 200' well. That after using a piston pump for many years. Jet pump is very inefficient. Water head is usually only 15 feet down - so even an in-house shallow jet bolted to the pump worked OK but wasted electricity. Later, I installed a deep-well jet with two pipes -thus putting the jet down near the well bottom. Worked better but still a power waster. Finally installed a submersible 1/2 horse, 220 VAC pump. The deep-well submersible pumps much more water and uses a lot less electricity. It is much more efficient.

    I'd still prefer to have gravity feed water to my home some day if I get around to it. I've own several high-flow springs on the mountain top behind me. But, building a reservoir and putting pipes five feet deep a 1/4 miles is a big project. I have backhoes and dozers, but so far have never gotten around to it.

    Our montly electric useage was 600-700 KWH per month before we trimmed down, when we were first thinking about installing solar. Changed a bunch of appliances, CFL lights, removed the electric clothes dryer and hot water heater, etc. Got down to 280-300 KWH per month and then put in the solar.

    Last year, we used more electric than we made in October, November, and February. During some summer months, we made twice more than we used. I keep close track since we are grid tie the power company pays us at the end of every calendar year.

    My system is grid-tie and battery backup, which I had to design myself when we put it in. Now, it's becoming more common and there are factory designed systems available. I've got dual Outback inverters and dual Outback MX60 controllers/chargers along with a Rolls/Surette battery bank. I'm glad I did it this way. We've had two long power outages so far this year. My power was never interupted. A guy near me is on grid-tie solar and no battery bank. When the power was out, so was his solar.
  5. mikeathens

    mikeathens New Member

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    I looked at the nyletherm and it appears a bit more complicated to install, and uses the existing themostat...and remains connected to one of the elements. It also runs on 220 vs. 110. They're probably both about the same in performace, though.

    The one i posted a link to runs at 690 Watts (115v, 6A), and according to testimonials and mfg. data, runs 3-4 hours/day...that's a total of 2.8 kWh vs. (based on the data plate on the tank) 13 kWh/day! I also figured that my on-demand propane tankless unit was consuming ~0.5 gallons of propane/day...or 14.7 kWh equivalents! I guess what makes them attractive is the cost of operating:

    Propane on-demand: 0.5 gallon @ $1.5/gallon = $0.75/day
    Electric resistence: 13 kWh/day @ $0.10/kWh = $1.30/day
    Electric heat pump: 2.8 kWh/day @ $0.10/kWh = $0.28/day (Assuming 4 hr run time/day - I've seen estimates at closer to $0.50/day).

    I'm planning to plug mine into a "kill-a-watt" meter, and see how it really measures up.
  6. kimko

    kimko New Member

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    Geothermal companies tried to market demand hwgenerators but had so much trouble with them they stopped ,this is due to the high condensing temp for the task, I'm a refrigeration mech and it doesn't sound like a good idea to me. Never seen one so just an opinion .
  7. mikeathens

    mikeathens New Member

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    My dad has a geothermal heat pump that is supposed to also produce DHW...he doesn't use it because the water is "tepid" at best.

    I also have a friend at work who has one of the air-source water heaters, and he loves his. He said it produces HOT water and is hassle free. I would also assume that it has to be worth somethin gif it's enery star certified and eligable for a $300 tax credit:

    http://aceee.org/consumerguide/waterheating.htm

    http://www.energystar.gov/index.cfm?c=heat_pump.pr_heat_pump

    I feel it's worth the "risk".
  8. gpcollen1

    gpcollen1 Minister of Fire

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    I have the Nyletherm unit myself...

    http://www.nyletherm.com/waterheating.htm

    Hard for me to do any energy comparisons year over year or anything b/c I am continually changing things. This unit is great in that I get my garage/cellar Air conditioned and dehumidified in the summer while it produces hot water. As you said, it kicks on instead of the lower element on the hot water heater. I am a do-it-yourselfer but regardless, this unit was easy to install into the HW heater - A wire or two, some pex and wallah! The guys at nyletherm are pretty nice on the phone too!
  9. velvetfoot

    velvetfoot Minister of Fire

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    I didn't realize indirect hot water heating with oil cost so much.
    These things are interesting as well for potentially doing double duty in the basement for dehumidifying.
  10. Corey

    Corey Minister of Fire

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    Interesting idea. I've seen them mentioned a few times before- but never heard any direct ratings of them. It is a bit funny that you can go to walmart and buy a 7k btu window air conditioner for $175 bucks. If they make that unit so it has a couple tubes that warm water, it's suddenly worth $700!

    I believe there are also some HX units which fit on an actual residential AC condenser. You basically pipe the compressed freon through the HX to heat your water and get rid of the relatively high grade heat - then through the air cooled coils to dump the rest.
  11. Wet1

    Wet1 Minister of Fire

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  12. Wet1

    Wet1 Minister of Fire

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    If you don't mind me asking, what was the cost of your system?
  13. gpcollen1

    gpcollen1 Minister of Fire

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    I think I got mine for 600-700. I think that is pretty good given that it seems like much more of a commercial product than a window a/c unit does for sure.
  14. Wet1

    Wet1 Minister of Fire

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    Sounds reasonable to me. Did you order directly from the manufacturer? If not, who carries them?
  15. Shipper50

    Shipper50 Minister of Fire

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    I am very interested in any ones findings on the above posts. I have an 10 year old electric hot water heater and I think its the main cost of my bill every month as I don't use my electric furnace due to burning wood.

    Thanks
    Shipper
  16. Wet1

    Wet1 Minister of Fire

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    I contacted Nyle about their Nyletherm 1 HPWH. It would appear they are now out of stock of these units. In fact, they have licensed the design to another company, North Road Technologies. They anticipate production in March... but you know how that goes.
  17. Wet1

    Wet1 Minister of Fire

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    A question about the AirGenerate A7... what happens with the condensation that is developed form this heat pump? I don't see a condensate pump mentioned anywhere. What I did notice is they have drastically increased the price on the A7 from $499 to $699 in the last few months, ouch! Supply and demand I guess...
  18. mikeathens

    mikeathens New Member

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    Wet, from what I can see (I downloaded installation instructions), this is a gravity flow setup for the condensate. It runs to the fron of the unit, and then down a tube. Mine will go into the washer drain. You can pick up a 110 v condensate pump at pretty much any hardware/plumbing store.

    I did see a site that sells the air tap with free shipping. Guess I had better get on the ball before everyone on here buys them out :eek:hh:
  19. Hansson

    Hansson Feeling the Heat

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  20. Wet1

    Wet1 Minister of Fire

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    Thanks Mike. That's what I assumed as well, but I did see a review on Amazon where the reviewer mention having to insulate because of condensation issues, that's why I asked the question.


    Hansson... 404 Not Found.
  21. Hansson

    Hansson Feeling the Heat

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  22. mikeathens

    mikeathens New Member

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  23. gman1001

    gman1001 Member

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    hey there - not to say things have not improved but here is my experience with NYLETHERM.

    About 5 years ago, the State of CT offered the NYLETHERM product for free to those who heated thier houses with electricity (me) and had an electric HWW.

    A contractor came and installed the unit, it was pretty simple, and yes it replaced the lower heating element and has a neat backflush pipe system.

    Basically the unit was crap. It was not UL approved and continually ran and ran and ran. Circuit boards melted continuasly and the poor guys from NYLETHERM and the HVAC contractor was at my house non-stop.

    Someone else posted that NYLETHERM was looking to manufacture more units soon. Thats exactly what they told me after my 10th unit melted down. By then I'd had enough and ripped the system out.

    I'f I had the time, and two less kids who demand alot of hot water, I'd try to work with/install a Solar Hot Water system instead, at least we know the sun doesnt need UL certification!

    I'm a believer in the Heat Pump Hot Water theory, thats why I jumped on board. Maybe in the future this will become more reliable.

    Food for thought...
  24. mikeathens

    mikeathens New Member

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    Maybe that's nyletherm...I need to get the brand name from my coworker that he has. Like I said previously, he has one that's been in service for 10+ years, and he swears by it.
  25. gpcollen1

    gpcollen1 Minister of Fire

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    I can only speak to my experience as I did not have one single issue. Maybe I will and maybe I wont - we will see.

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