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  1. #1
    Join Date
    Jan 2011
    Posts
    11

    Electric Heat Pump Water Heater

    With our electric hot H20 8 years old, and the tax credit expiring 12/31/2010, I decided to purchase a Electric Heat Pump Water Heater.
    Our home is currently 100% electric, no gas applicance nor furnace.
    Lowes had 10% off (for $1450), plus 30% fed tax credit (additional $435 off), plus 10% state tax credit ($145 off) means cost is approx $905.

    This was installed week of 12/27, has anybody else here installed one of these Electric Heat Pump Water Heaters?
    I've read the heat pump makes noise, did you experience relatively "loud" noise?
    My noise level is not bad at all, being located in same room at GeoThermal unit (dedicated HVAC utility room with closed door).

    http://www.geappliances.com/heat-pump-hot-water-heater/

  2. #2
    Join Date
    Jan 2011
    Posts
    11
    Here are picts of the install




    Tank was taller, so lots of re-plumbing and sweating 1" pipe. We have 1" supply thru the home for good water gpm flow to all fixtures.






    Since we've been using this for 3+ weeks I'll post my experience shortly.....some lessons learned for others considering this an an option......

  3. #3
    Join Date
    Jan 2011
    Posts
    11
    My only real gripe with it so far is GE tech supported directed me NOT to hook up the Hot Water Convection Loop, according to them their Hybrid air pump hot H20 heater has temp probes in the tank that help it intelligently decide the best mode to operate in.
    Having a Hot Water Convection Loop plumbed into the bottom of the tank (std practice) will confuse their algorithms and the tank will shut down and display error codes.
    For me, and people who had some method to keep the hot water supply pipe ready, via convection loop/other, this is a big issue.

    This was NOT in the instructions either, I took it upon myself to call them and ask.

    Prior, it took 15-ish seconds for the shower to be usable/hot, now 90-ish seconds. Ive timed it, thats approx 3.5 gallons of water, as seen in the 5 gallon bucket. My calculations showed 2.6 gallons for the 65 foot 1 supply pipe, so that matches pretty closely.

    In the big picture, Im not sure if its more energy efficient to waste 3.5 gallons/day, and have the more efficient Hybrid air pump heat the water, or having traditional heater with Hot Water Convection Loop.
    My intuition says the Hybrid air pump hot H20 heater overall should be most efficient, but Im questioning did GE take this into account for their 62% energy savings claim, Id say not.

    I'm trying to follow-up more on this issue with GE directly.

  4. #4
    Join Date
    Jan 2011
    Posts
    11
    To the pros here: Am I the only one in the USA who has this issue?

    Or are you also plumbing the GE Hybrid Hot H20 same, w/o a convection loop?

    How about the other brand Hybrid Hot H20's?

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,257
    Quote Originally Posted by mtbdudex View Post
    To the pros here: Am I the only one in the USA who has this issue?

    Or are you also plumbing the GE Hybrid Hot H20 same, w/o a convection loop?

    How about the other brand Hybrid Hot H20's?
    Convection loops beat the hell out of any water heater. It will constantly short cycle as the heat is lost to the home via the hot water supply. These are real energy hogs and are tough on heat pump water heaters.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
    Hybrid sucks heat out of the space its in, which if you heat that space, you haven't gained anything. This is a very high tech solution for a low tech problem. Wash your clothes in cold water (yes it works just fine), and cut your water heating bill dramatically!
    And buy 2-3 water heaters for the price of one hybrid (with all of its maintainance) (and you don't need a $1000.00 washer either; by far most of the energy used goes to heating the water...)

  7. #7
    Also, I have yet to see a comparison of a HP water heater to a gas water heater...
    6 years ago I installed a new gas furnace, and converted electric water heater to gas, and despite adding gas hot water the gas usage went down. Electric bill went down dramatically.
    Well insulated gas water heaters are very efficient. And cheap. And proven.

  8. #8
    Join Date
    Apr 2008
    Location
    Northwest Arkansas via Chicago Area via Straight Up from There on Lake Superior
    Posts
    1,411
    Quote Originally Posted by teddy bear View Post
    Convection loops beat the hell out of any water heater. It will constantly short cycle as the heat is lost to the home via the hot water supply. These are real energy hogs and are tough on heat pump water heaters.
    Regards TB
    Just a mere HO here but do you mean a hot water circulating pump when you say "Convection loops"? If so, I need one in order to reduce water waste and long waits for hot water in the kitchen and master bath and I suspect the downstairs bath which we use very little. I tried letting the circulating pump run 24/7 and the NG cost was up and the electric too, I suspect.

    We discovered that the original HO had an X10 controller on some lights. I didn't know what that was until I researched it. It sends control signals across your inside power lines to controlled X10 units. The light bulb came on and I found an X10 appliance controller to plug the circulating pump into and a cheap X10 control panel and now we use these. The whole original X10 deal cost under $75 as I recall. Now all we have to do is hit the right on button in the kitchen (or the MB where we added another control panel) and the water is hot in like 1 minute with absolutely no water waste. If I am taking a shower, the water is hot before I am ready to jump in. Only issue I have is that the furnace running near the circulating pump does scramble the X10 signals and require pressing the control button several (many) times occasionally. Still a lot cheaper than water waste or utility waste.

    Hope this helps.

  9. #9
    Join Date
    Jan 2011
    Location
    Lancaster county PA.
    Posts
    34

    Smile dear mtbdudex & every one else

    A properly insulated, properly controlled domestic hot water circulation loop will save you money in energy and in water savings. Here is how. The main hot water line that is part of the loop plus the return line from the farthest faucets need to be well insulated. The loop circulator should either be on a timer or controlled by a return temp sensor. In my personal home I have both. My gas bill for water heating dropped by 1/3 and my wasted water down the drain waiting for hot water to arrive went to nothing. Most people who say hot water loops waste energy have not thought through the process. We used to wait 60 seconds for hot water to arrive at our farthest faucets from our water heater. This was 60 seconds worth of water going down the drain while 60 seconds worth of cold water flowed into the water heater to replace the water going down the drain. The water heater then has to heat all this cold water up to the set temp. Now we open the faucet and in 1 second, hot water is coming out. No wasted water, no wasted heat. I actually double insulated my water lines, using 5/8 id, 3/8 wall pipe insulation and then put 1 3/8 id, 3/8 wall over that. I love saving money and now we don't have to wait for hot water. Its a win/win situation.
    Now, about your situation. Pipe your return line from your loop into the preheat tank from the geothermal rather than the heat pump water heater. That way you will not "mess" with the water heaters design parameters. I have been an HVAC service tech for 23 years and have piped many desuperheater preheat tanks this way. Be sure to include a flow check on the loop so no water can flow from the preheat tank directly to the faucets.
    Good luck with the project.

  10. #10
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,257
    Heat pump water heater are efficient when they heat cold water to hot water. Reheating warm water lowers the cop dramatically mkeing then operate at the high end of the compressors limit.
    Insulated recirculation loops use energy. How much is the issue. Depends on many things. My farthest length takes about 2 minute at 3 gallons per min. 6 gal. of water down the drain. Cost for wasted water is the cost of pumping and softening. City water could $<.001 or put in your number. Routinely heating a loop cost ??? how much and with some how cares. But it is not free. Its a personal thing. So far I have not observed a recirculate loop that is less than a conventional hot water feed. Compare real operating cost and you decide. Water heaters generally do not like being mixed by recirulating loop pumps. We manufactured the most efficient heat pump water (Therma-Stor- COP +3) for years.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  11. #11
    Join Date
    Jan 2011
    Location
    Lancaster county PA.
    Posts
    34

    Smile still thinking "old school"

    First, let me say I used to say and believe the same thing, that hot water loops are convenient, but are hard on water heaters and really waste energy,so please don't be offended. I was wrong. Look at it this way. The key is the well insulated pipes in the loop and the controls. The pipes just become part of the water heaters storage tank. My loop circ draws .40 amps at 120 volts, that = 30 watts. It runs for 30 seconds at a time and does this 1 to 2 times per hour or whenever the loop temp drops by 2 degrees, and only between the hours of 5AM-9PM. Thats a total of 16 minutes a day times 30 watts = 2.91KWH per year or about 50 cents/year. Now lets say you open the hot water faucets 20 times a day and run 2 gallons down the drain each time waiting for hot water to arrive. Your water heater has had to heat up that much more water, 40 gallons a day times 365 days a year. Thats 14600 gallons a year. No wonder water heaters wear out so fast. Mine is 18 years old and still going strong. It is power vented propane gas, nothing special other than we do not ask it to heat nearly as much water per year as others without hot water loops. Obviously, we save the gas not heating up all that wasted water. It also saves my water softener 15 regenerations per year, and my 16 year old well pump that much electric in pumping all that water to my home. Also, most water heaters come on when their temp drops 8 - 12 degrees below their setpoint, so they are almost never heating cold to hot, but warm to hot. Hope all this helps.

  12. #12
    Join Date
    Feb 2004
    Location
    Pacific NW
    Posts
    564
    50 cents/year -- we wish!
    You forgot some minor details......like the heat loss from the pipes
    U forgot 2x per hr x 365 x 16hrs x 3gal* x 8.4#/gal x 2F x 1btu/# = 17.2 kW-hrs, or $3 more per year. * 3 gal is using number form another post

    reverse calc , if your 2x per hour is for 2F drop, then 3/4" pipe = approx 32 sq inches of area losing heat per foot of pipe run.
    3/4" pipe holds approx 5-1/2 cu in of water (0.2#), so a 2F drop in 30 min means 0.8 BTU/hr loss per foot of pipe.
    Thus, a 20 foot run (40 ft total) loses 32 BTU per hour = 55 kw-hrs or $9.35 per year at your rates, not 50 cents -- still affordable though <G> .

    So, let us guess how much insulation you have: 32 in sq * 40 ft = about 9 sq ft for a 32 BTU/hr loss. Reverse calc then results in roughly 2 BTU/hr/sq ft/degF (too lazy to grab a calculator for more accurate number) or an R-rating of 0.5, which is just about what a 1/2" thick foam pipe cover provides.

    I did not even try to calculate that in winter that $10 of lost heat actually does heat the home, but that in summer you need to run the AC to get rid of the extra.....

    Own home case in regards to H2O HP, in PNW dont need much AC, so the big advantage in HWH in summer is lost. Do have GSHP, so could pull the HWH from the ground, but payback time (in just time spent installing) still does not make it worthwhile for me, and I can build my own HPs from scratch if needed.

  13. #13
    Join Date
    Apr 2010
    Location
    southern california
    Posts
    535
    All of these replies are interesting. The standard hot water heater in itself is only efficient when it is firing. Heat loss thru the jacket wall is tremendous in the standby mode, which is most of the time. TeddyBear , Therma-Stor, what a small world. There are several ways to address recirculation loops,Metlund, Laing, Taco all have alternative approaches. No mention here for tankless or solar , which both have their places as far as saving energy. The real question is just how much does one want to save in energy, and what is the ROI of the equipment needed.

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