Electric Tankless or new Heat Pump type

Discussion in 'Tankless Water Heater Forum' started by bmcgin, Oct 28, 2010.

  1. bmcgin

    bmcgin New Member

    Messages:
    30
    Location:
    PC Beach, FL
    House has 2 hot water heaters, both electric. I want to replace one of them because it is 11 years old and it’s on the second story of the house. If she blows, it’s not gonna be pretty.

    What would you recommend? Electric Tankless or newer Heat Pump type I’m not going to do gas because we have kids sleeping close to hot water/utility room.

    House is in north FL. This single hot water tank is a 40 or 50 gal and supplies:
    2 full baths. Located within 15 feet of hot water heater. One bath is hardly ever used.
    1 kitchen sink
    1 dishwasher
  2. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    You'll need heavier wires for a tankless, and they click a lot.

    How much to put a drain pan and a drain line for this heater? A water level detector in the pan is about $16.
    A condo I sometimes do work in has this drain/detector arrangement for their wall mounted heat pumps so both together must give pretty high reliability.
    Last edited: Oct 28, 2010
  3. bmcgin

    bmcgin New Member

    Messages:
    30
    Location:
    PC Beach, FL
    Right now the existing hot water heater is the old tank type with 220 (or is it 240) volts. The tank does sit inside of a drain pan and the pan has a pvc line or something that drains outside. If the tank blows, there's no way the pan and the drain would handle the amount of water rushing out. So it would be a mess.

    I don't want to take chances and I think it's worth replacing it. At the same time, I think electricity is getting expensive and I want to lower consumption.

    I'm really not sure if the electric tankless are very good. Seems like a lot people are not happy with them where as the gas tankless people have a higher percentage of satisfaction. From what I gather, it’s hit or miss or a 50% chance that I’ll regret putting in an electric tankless.

    On the other hand, the hybrid heat pump tanks always satisfy. No one ever says anything about hot water sandwiches, the water running cold, the need for expansion tanks, etc…

    So I’m leaning towards the heat pump system because there is no ambiguity as to how good it works. It won't solve the problem of it blowing apart and water going everywhere. It does minimize the risk.
    Last edited: Oct 28, 2010
  4. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    I'd worry about heat pump reliability because it is more complex.

    The likelihood of a tank blowing is very small because these kind of events make for bad press, but if you add a Y fitting and another temp/pressure overload valve the likelihood will be even smaller.
  5. bmcgin

    bmcgin New Member

    Messages:
    30
    Location:
    PC Beach, FL
    What do you think about the electrical tankless heaters vs the heat pump?
  6. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    In a month in Germany with their tankless heaters I did not take a single shower where I did not get some cold water on my head. I just could not get the hang of it.

    This does not apply to taking baths or running water in taps.
    Last edited: Oct 28, 2010
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    Your fear of gas is unfounded. There are millions of gas WH installed around the country. The risk of a leak is small when installed properly. they have faster reheat capability and usually, lower costs.

    But, WRT an electric, or any WH for that matter, they rarely go from working to a catastrophic failure. It is almost always a progression of slow leak to faster leak. now, if you weren't home for a week after it happened, the likelyhood of overloading the drain pan and drain are small. There's a device that can stop the water loss too, check out www.wagsvalve.com , it will shut the water off if it detects a significant leak (and would also cut off the gas, if it was hooked to a gas WH).

    An electric WH is essentially noiseless. A heat pump version has a compressor, so you may not want it sitting close to your bedrooms. They aren't noisey, but do make some sounds - it does have a motor (compressor) in it. A gas WH is pretty quiet unless you opt for a power vented version.
  8. bmcgin

    bmcgin New Member

    Messages:
    30
    Location:
    PC Beach, FL
    As a complete novice and a “trying to get educated” consumer, it looks like from a performance aspect people like the gas tankless and not so much the electric tankless. There is still an element of the tankless failing to work as anticipated.

    I wonder if I install one if it will work as good as my old fashion tank. And if it doesn’t than I’m gonna kick my slef in the head because spending $250 more a year for the luxury of hot water is money well spent. Jeezzz, this what I spend a month on cell phone and cable tv. So I would have risk $2500-$4000 for little return and no one can assure me that it would work as good what I have. Just not worth it.

    The other issue I’m facing with gas is the installation. I would need to run a gas line to the second floor and then vent. All in all just too much money.

    The heat pump models at least give me assurance that it will work. As far as noise goes, my hot water heater is in the same utility room as the ac/heat unit. So it’s most likely going to be manageable. I doubt if it’s louder than that.

    One thing I’m considering is getting the add on type of heat pump unit and putting in the attic. That’s probably over kill. Although it would be nice to install so that the dehumidifier is above the stairs working on the whole house. Here in FL I could run a dehumidifier all year and it’s just get even more comfortable.

    Someone needs to develop a single system that takes care of ac, heat, refrigeration. freezer, hot water and dehumidifying. If one system fed into another system, there would have to be some energy savings and added comfort.

    Thanks for the tip about the shut off valve. I gotta get this.
  9. Furd

    Furd Engineer

    Messages:
    446
    Location:
    Wet side of Washington State
    The most cost-effective solution is to simply put another tank-type electric water heater in place.
  10. bmcgin

    bmcgin New Member

    Messages:
    30
    Location:
    PC Beach, FL
    Here’s the rough numbers:

    Good old 40 gal --works every time—tank with energy smart (from Lowes):
    Purchase: $319
    Install: $350
    Total: $669
    Yearly cost to run: $508

    GE 50 gal hybrid:
    Purchase: $1600
    Install: $350
    Tax Rebate: $480
    Total: $1470
    Yearly cost to run: $198

    On day 1 the hybrid costs $800 more than the tank. Each year the hybrid will save $310. So 32 months (2 ½ years) is the breakeven point.

    If it lasts for 10 years then the total savings is $2635. This is a general number and makes gaping assumptions, like the numbers on the energy guilds are consistent with usage and Obama is not able to pass the Cap and Trade which would increases the savings by at least another 30% more to around $3200 (give or take a few hundred).

    This added by Terry
    The hybrid electric needs a drain, so figure a bit more on installation time and material.
    [​IMG]
    Last edited by a moderator: May 18, 2011
  11. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    One reason for this post was your risk aversion, so to be consistent you should attach a negative dollar value to catastrophic failures or other failures. If it's -$1000 and the likelihood is 0.1 [10%], then it's -$100 in the equations.

    These kind of eventualities can swamp out the gains. That's why getting reliability data and likely failure modes from manufacturers is like pulling teeth.
    Last edited: Oct 29, 2010
  12. Dana

    Dana In the trades

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    3,028
    Location:
    01609
    Did you use the EnergGuide dollar numbers, or did you calculate them based on your actual utility costs?

    In FL, if the hybrid is inside the house as opposed to an un-conditioned garage or outdoors, for every ~4kwh difference in water heating power you'll also get another kwh in reduced cooling cost during the cooling season. Those "extra" savings might be completely eliminated by the in increase in space heating costs if you heat with resistance heaters like electric baseboards, but not if you heat with a heat-pump.
  13. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    In your area and application I would consider installing the Stiebel Eltron Accelera 300 instead of the GE. It has a more purist operation of the heat pump and offers the highest EF...

    Better yet why not consider solar?
  14. bmcgin

    bmcgin New Member

    Messages:
    30
    Location:
    PC Beach, FL
    I just used the Energy Guide numbers to estimate. These are accurate enough to get a rough idea the hybrid is worth the extra upfront costs.

    Since all the plumbing is already run, I would put the heater in a utility room on the second floor. I could close the a/c supply to the room during the summer. It would be nice if these water heaters had a air hose connection so I could run it up to the attic and let it draw the hot air. I guess this is overkill....

    The Stiebel 300 is 80 gal. which is too much. Is there another brand which is comparable?
  15. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    No! The Rheem/Ruud, GE and AO Smith models all use higher wattage elements to make the Heat Pump Water heaters more palatable for use in markets where they are less suited...

    Only the Steibel Eltron uses a smaller resistance heating element for highest efficiency...
    It is the only one that can be installed with a 15 amp circuit the others need a 30 amp circuit....
  16. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,319
    Location:
    New England
    The heatpump versions typically have slow recovery rates, so having more hot water stored may be a big advantage. In order of typical response (faster first), you'd have: gas, electric, heatpump. So, especially if the 80-gallon job was well insulated, it may not be too large (from a use point, maybe not from a physical size issue). If a heatpump version has resistance backup, on some uses, it may not be any more efficient than a typical electric WH.
  17. bmcgin

    bmcgin New Member

    Messages:
    30
    Location:
    PC Beach, FL
    GE: 30 amp, Smith: 25 amp, Rheem: 22 amp, Steibel: 15 amp

    Energy Factor:
    GE: 2.35, Smith: 2.4, Rheem: 2.0, Steibel: 2.5

    So the Steibel will draw less amps and makes the best use of energy. Looks like a very good product.

    Only problem is the size, it’s 26” round. I have space for 24”. So unless I want to start revamping ductborad, it’s not going to fit.

    My current water heater is actually a 40 gal and we’ve never run out of HW, so a 50 gal should be sufficient. 99.9% of the time this water heater supplies 1 full bath (for a 4 yr old), kitchen sink and dishwasher.
    Last edited: Oct 30, 2010
  18. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Actually the Stiebel Eltron Accelera 300 draws a maximum of 9.16 amps.

    What you should also look at is the 1st hour delivery...
    Your present unit is probably in the mid 50 gallon range....
    Stiebel Eltron Accelera 300: 78 gallons
    GE GeoSpring Hybrid: 63 gallons
    Rheem/Ruud Hybrid: 67 gallons
    AO Smith Voltex: 70 gallons

    But the AO Smith Voltex is also an 80 gallon tank like the Stiebel Eltron Accelera 300 so there might be dimensional issues with that as well.

    The Stiebel Eltron Accelera 300 has a single 1750 watt element.

    The AO Smith Voltex upper element is a 4,500-watt element and the lower element is a 2,000-watt element.

    The others all use 2-4500 watt elements...
    Last edited: Oct 31, 2010
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