Another water heater query - hybrid water heaters

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wageoghe
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Another water heater query - hybrid water heaters

Post by wageoghe » Sun Jun 08, 2014 2:37 pm

Recently there was a post on the forum about getting a new water heater:

http://www.bogleheads.org/forum/viewtop ... st=2083380

A while back there was another post on the same topic, in which I suggested that the OP might want to consider a hybrid water heater. I mentioned that I might consider one the next time we have to replace our water heater.

http://www.bogleheads.org/forum/viewtop ... g#p1614373

One example of a hybrid water heater (GE GeoSpring):

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

A hybrid water heater, for those not in the know, uses heat pump technology to heat the water (with electrical resistance heat as backup). A hybrid water heater uses much less electricity to heat water than a conventional electric water heater.

In reading the reviews for the GeoSpring (for example, here: http://goo.gl/RG48uY ) one can see that it generally receives very high marks (4.5/5 and 90% would recommend), but there are also quite a few negative reviews due to reliability issues. From what I gather early models were more problematic than the current generation.

Does anyone have firsthand experience with this, or similar, water heater? We might be in the market for a water heater and I am still considering a hybrid. We live in northern AL and our water heater is in the garage.

I am not necessarily looking for a payback calculation. Just any first hand experience, especially as regards reliability (and/or GE's response to lack of same).

JeffAL
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Re: Another water heater query - hybrid water heaters

Post by JeffAL » Sun Jun 08, 2014 6:35 pm

I have a GE Geosprings purchased about two years ago. Not a 1st gen model. The compressor failed after 9 months. Apparently a not uncommon occurrence. I regret the purchase considering the price premium.

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Re: Another water heater query - hybrid water heaters

Post by LongerPrimer » Sun Jun 08, 2014 10:32 pm

Have you thought about gas instant water heater?

Goblue97
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Re: Another water heater query - hybrid water heaters

Post by Goblue97 » Mon Jun 09, 2014 1:33 am

Perhaps you already looked at this but have you calculated the energy savings and when your more efficient heater will break even as compared to the standard heater?

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wageoghe
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Re: Another water heater query - hybrid water heaters

Post by wageoghe » Mon Jun 09, 2014 8:45 am

Thanks for the feedback so far.

JeffAL - So, did you have the unit repaired and are you still using it? Do you still have it but are now only using resistance heat? Did you have it replaced?

LongerPrimer - Our current water heater is electric and we are looking to replace with electric. We don't have gas. Gas is available on our street, but we don't have a line from the street to our house.

GoBlue97 - I haven't done the calculation. For me, this is not strictly a payoff decision. I am confident that the payoff is there. The real question for me is the reliability of the unit.

saladdin
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Re: Another water heater query - hybrid water heaters

Post by saladdin » Mon Jun 09, 2014 10:32 am

I looked into it but the requirements of where you could/couldn't place the unit and the amount of room needed was too much. In my neck of the woods water heaters are usually in the main house in the utility room with washer/dryer with very little wiggle room. My area has very little houses with water heater in garage and having a basement in general is rare. Also, if you have a large family the electric resistance will cut on to provide the extra hot water so less efficiency there.

I just couldn't get the breakeven close enough for the extra cost plumbing, electrical etc... including my cheap rate of $0.0875 per kwh.

http://www.greenbuildingadvisor.com/blo ... s-come-age

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Re: Another water heater query - hybrid water heaters

Post by saladdin » Mon Jun 09, 2014 10:37 am

wageoghe wrote:Thanks for the feedback so far.

JeffAL - So, did you have the unit repaired and are you still using it? Do you still have it but are now only using resistance heat? Did you have it replaced?

LongerPrimer - Our current water heater is electric and we are looking to replace with electric. We don't have gas. Gas is available on our street, but we don't have a line from the street to our house.

GoBlue97 - I haven't done the calculation. For me, this is not strictly a payoff decision. I am confident that the payoff is there. The real question for me is the reliability of the unit.
You really should do a BE. These aren't placed just anywhere and my research showed potential plumbing and electrical changes which can run up cost. Even if you have semi expensive electricity BE could be 10 years any way.

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deanbrew
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Re: Another water heater query - hybrid water heaters

Post by deanbrew » Mon Jun 09, 2014 12:35 pm

I bought a GE Hybrid water heater in 2009. It had a coolant or condenser failure at the two year mark and another at the four year mark. Fortunately, and uncharacteristically for me, I had purchased Lowe's extended warranty when I bought it. The warranty covered the repair at the two year mark (which would have cost over $700), but when it failed again earlier this year, the extended warranty company decided to pay me the full price I paid for the water heater rather than repair it, because they couldn't find anyone to repair it in a timely manner.

I took the money and bought a new one in March of this year, again at Lowes, and again with the 10-year extended warranty. I decided to do so because I like how it works and it is now made in Kentucky. The first one was made in China, and the new ones are supposedly better made. I bought the new one on sale at Lowes for $1,000, which is about $600 less than the one I bought four years ago. Since the warranty company paid me my $1,600 back, I was able to buy the new heater, have it installed and keep a couple hundred bucks. I also got a $300 energy efficiency rebate from the government.

So, I certainly can't vouch for reliability, as my prior unit went bad twice. I'm hoping the new USA-made unit is more reliable, but I spent $100 on a 10-year warranty as an insurance policy. As I mentioned, I very seldom buy such warranties, but the warranty price seems reasonable given the time frame and relative complexity of the appliance.

In addition to energy costs, the main reason I decided on a hybrid WH is because my basement used to get very humid and warm during the warm months of the year (due to the NG furnace firing up to heat our water). Now, the hybrid WH acts as a defacto air conditioner, as it pulls heat and moisture out of the air as it operates. My furnace rarely kicks on to heat water, so I have a nice dry, cool basement in addition to hot water. You need to install it in an area with sufficient volume of air for it to work properly, and the warmer the room the better in terms of the heat pump's operation. My sizeable, warm basement seems ideal. I don't have a typical installation, as I still have my furnace hot water system and use it as a secondary hot water source.
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Re: Another water heater query - hybrid water heaters

Post by kcb203 » Mon Jun 09, 2014 1:34 pm

Does anyone make a water heater that uses waste heat thrown off by the A/C during the summer? It's a shame that all that energy is wasted while at the same time we're paying to heat something else, often in the same room.

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Re: Another water heater query - hybrid water heaters

Post by Spirit Rider » Mon Jun 09, 2014 5:49 pm

kcb203 wrote:Does anyone make a water heater that uses waste heat thrown off by the A/C during the summer? It's a shame that all that energy is wasted while at the same time we're paying to heat something else, often in the same room.
The engineering mechanics of this would be very involved. You would have to couple the low/high pressure refrigerant lines in a sophisticated manner and have to deal time differences in their relative loads.

My guess is that the engineering/manufacture costs would also far out weigh any potential energy cost savings. Also, what is the demand that will cause people to replace both systems at the same time. I doubt there is any market.

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wageoghe
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Re: Another water heater query - hybrid water heaters

Post by wageoghe » Mon Jun 09, 2014 7:28 pm

They did something like this to heat a pool on Ask This Old House a couple of seasons ago.

Here is the product they used.

http://www.hotspotenergy.com/pool-heater/

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Re: Another water heater query - hybrid water heaters

Post by meebers » Mon Jun 09, 2014 8:31 pm

I cannot justify anything but a standard natural gas water heater. I have a 50 gal unit in the garage. With the exception of the gas fireplace that is used in the winter, my gas bill is about $30 a month for hot water. The actual gas that is used is about $12-15 while the remaining part of the charge is utility charges and tax etc. Payback for an instant water is too far off in the future, I cannot see that it would save me any money at all and if it did, maybe the NGas itself would drop to $10 or so.
There was another question of using the AC/Heatpump to heat the water. I had a system installed at my last house that used it. A box about 10x10x4 was mounted on the wall next to the unit, the AC line went into that box thru a small heat exchanger (about 3 wraps of copper pipe) then continued on to the compressor. The hot gas heated the water that was returned to the Water heater thru the normal drane valve via a small recirculater pump. The only problem at the time was if the kids all took showers at the same time while the wife was washing clothes etc, this exchange could not keep up, but that was rare. Flip the breaker on for a short period and then back off. You can see the box I used here: http://techcrunch.com/2011/06/12/air-co ... er-heater/

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wageoghe
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Re: Another water heater query - hybrid water heaters

Post by wageoghe » Wed Jun 11, 2014 8:22 am

Thanks again for everyone's responses.

deanbrew - Thanks for the detailed recounting of your experience. I too rarely buy extended warranties, but I have sometimes bought them when I have purchased something that uses new (or newish) technology or something that I find desirable, but that might have unknown reliability.

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Re: Another water heater query - hybrid water heaters

Post by Scotttheking » Wed Jun 11, 2014 12:45 pm

kcb203 wrote:Does anyone make a water heater that uses waste heat thrown off by the A/C during the summer? It's a shame that all that energy is wasted while at the same time we're paying to heat something else, often in the same room.
If you get a geothermal heat pump, you can get a desuperheater: http://www.geojerry.com/desuperheater.html

Google found this product for air source: http://www.turbotecproducts.com/EPhome.html

Quick reading suggests the added complexity outweighs the cost savings in most instances.

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Re: Another water heater query - hybrid water heaters

Post by Mike83 » Thu Jun 12, 2014 9:10 pm

There are two questions raised in this thread that I can respond to.

First, I have a US-made GE Geospring water heater, now 18 months old. I chose it because it provides the same savings as a rooftop solar unit at about one-fifth the installed price, and it does not require roof penetration, extended plumbing lines, or hurricane engineering in my south florida location. Also, it is exceptionally efficient in a garage in a warm climate like mine. It had an immediate and lasting effect on my electric usage, reducing my bill $35 a month, so it will have a three year payoff. Would be even better if my kids still lived with us. I have had a house full of guests for a week and hot water supply never came up short. These are very good solutions for those in the sunbelt. If you live up north, I can't be sure what the payoff would be, but you would likely put it in a basement, where it would dehumidify and add cooling that you likely don't need. Given the newness of the product, I also opted for the Lowe's 10year extended warranty of about $100. Other than electric, my only option was propane by tank. Although I have such a tank, propane usage would be expensive. If you have access to piped natural gas, that is still likely your most cost efficient option, plus, up north you get a bit of free heat if it's in the basement.

Second, someone asked about recovering air conditioning created heat to heat hot water. Yes, such devices exist. Google them as 'desuperheaters'. These recovery units attach to the outside unit of central ac system. They are essentially a pipe that passes water from your hot water heater past the desuperheater to capture waste heat. I have two outside ac units and a desuperheater on each, thus two loops back to my hot water heater. I have had these for 25 years (with on replacement). My prior owner was an ac contractor, and I inherited them. Again, in Florida, they are very effective since we run ac all the time. I have found that most ac companies do not bother with them, as they are a bit out of scope for them since plumbing is required. But they deliver very hot water to the tank. I have been told that super efficient ac units now on the market produce less waste heat, and therefore the desuperheater has less to capture. My current EER is about 13, which will go to 16 upon replacement. These numbers do not account for the fact that the desuperheaters, in and of themselves, increase the effective EER since they remove heat from the ac and help 'cool' the unit.

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sclaus
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Re: Another water heater query - hybrid water heaters

Post by sclaus » Fri Jun 13, 2014 9:36 am

I'm also interested in getting a hybrid water heater.

Anyone own a Voltex water heater by AO Smith?
http://www.hotwater.com/water-heaters/r ... al/hybrid/

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Re: Another water heater query - hybrid water heaters

Post by shaboob » Fri Jun 13, 2014 10:22 am

Spirit Rider wrote:
kcb203 wrote:Does anyone make a water heater that uses waste heat thrown off by the A/C during the summer? It's a shame that all that energy is wasted while at the same time we're paying to heat something else, often in the same room.
The engineering mechanics of this would be very involved. You would have to couple the low/high pressure refrigerant lines in a sophisticated manner and have to deal time differences in their relative loads.

My guess is that the engineering/manufacture costs would also far out weigh any potential energy cost savings. Also, what is the demand that will cause people to replace both systems at the same time. I doubt there is any market.
These exist. I read about them a while ago and coincidently, just had a conversation with my AC guy about them. They work pretty well normally, but may not be compatible with the new, higher efficiency AC units.
Hope is not a strategy. That's why we have contingency plans.

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Re: Another water heater query - hybrid water heaters

Post by shaboob » Fri Jun 13, 2014 10:39 am

Mike83 wrote:There are two questions raised in this thread that I can respond to.

It had an immediate and lasting effect on my electric usage, reducing my bill $35 a month, so it will have a three year payoff. .

.
Good to have a real data point. I'm in S. FL too and am considering this as a preemptive replacement for my 15 year old electric heater. No gas available in the boonies where I live.
Hope is not a strategy. That's why we have contingency plans.

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wageoghe
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Re: Another water heater query - hybrid water heaters

Post by wageoghe » Sat Jun 14, 2014 1:11 pm

Thanks for everyone's replies so far, especially those with real world experience with hybrid water heaters.

Any more information or experience anyone would like to share?

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Re: Another water heater query - hybrid water heaters

Post by ddj » Thu Jun 19, 2014 12:13 am

I've recently wondered if I'm irrational to not purchase a hybrid water heater: 50 gal electric costs $520/year, 50 gal hybrid ~$250. Payoff (incl install) in much less time (5 years) than expected life (10-15). Coolant/compressor breakdown, however, sounds miserable. I've heard these units are quite sensitive to being shipped improperly (not upright). Looks like reliability is a question, though, as some of you have noted, it's getting better.

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Re: Another water heater query - hybrid water heaters

Post by Valuethinker » Thu Jun 19, 2014 3:53 am

ddj wrote:I've recently wondered if I'm irrational to not purchase a hybrid water heater: 50 gal electric costs $520/year, 50 gal hybrid ~$250. Payoff (incl install) in much less time (5 years) than expected life (10-15). Coolant/compressor breakdown, however, sounds miserable. I've heard these units are quite sensitive to being shipped improperly (not upright). Looks like reliability is a question, though, as some of you have noted, it's getting better.
If you need to replace then yes it is worth looking at -- but make sure you buy an extended warranty.

If you don't need to replace it probably is not worth replacing immediately. Wait until you need to OR electricity rates get jacked up (sometimes the utility will offer a 'time of day' rate which means you can reduce your bill on the heater). Or wait until the utility gives you an incentive to install it.

(I am assuming there are no tax credits on replacing water heaters?).

There are few exceptions to the 'only replace when you have to' with major appliances/ home improvements:

- fridges if pre 1992 (1985 fridge 2000 kwhr pa, 2014 fridge 500-600)
- HVAC if very old/ inefficient (SEER 7-8, and it will decline from what it is rated-- you can get to SEER 15 now and with dual/ variable speed systems, greater comfort)
- switch to gas (from oil) for heating - oil is a global market affected by political disruption (Iraq this week), natural gas is a North American market with structural oversupply due to new technology
- a top loading washer with a front loading washer *if* you have high electricity rates and/or water restrictions (again, my mother got a credit for so replacing). Make sure you are comfortable with the issues with FL re detergents etc. Your energy and water consumption can drop by something like 70%
- incandescent or halogen lightbulbs with LEDs (had to run the numbers on this one, but for me at 22c/ kwhr it made perfect sense to dispose of a perfectly good halogen and replace w an LED bulb costing 6x as much-- the payback was 2-6 years depending on which light)

Getting a home energy audit and identifying where you could put more insulation and/or leakproofing is also worth it. Insulation is cheap relative to the gains it brings.

When you do replace, it's worth it to 'stretch' for higher efficiency. A hedge against higher future energy prices.

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Re: Another water heater query - hybrid water heaters

Post by Carl53 » Thu Jun 19, 2014 5:00 am

Ground loop heat pumps have a range of hot water supply options. They all use desuperheaters but one that we had also would heat water as a primary load even during winter when the unit was otherwise heating the house. Many supply supplemental heat to the hot water tank but the one we had had its own 75 gal tank. The water was extremely hot and had to have a mixing valve to drop it to 140 or less. The unit (back in the 80s) also had another heat exchanger that could heat the pool. Sadly it died as it was no longer cost effective to get special made parts from overseas and we went to gas fired replacement units.

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wageoghe
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Re: Another water heater query - hybrid water heaters

Post by wageoghe » Thu Jun 19, 2014 10:52 am

Thanks for the continued interest in this thread! Anyone that has something to share who has not shared yet, please jump in.

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Re: Another water heater query - hybrid water heaters

Post by WhyNotUs » Thu Jun 19, 2014 11:38 am

I looked it hybrids when I replaced my water heater but I live in a cool, dry environment and they are less effective here.
If I buy one with my credit card that offers extended warranty and saved all of the paperwork, I would have added a year of warranty without buying an additional product.
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Re: Another water heater query - hybrid water heaters

Post by 4nursebee » Thu Jun 19, 2014 12:52 pm

Instantaneous water heaters are likely much more efficient than anything mentioned here, I recall >85% effiecient either gas or electric. My Rinnai has needed no upkeep, > 10 years.

Keeping "X" gallons of water hot all the time is inherently less efficient.
4nursebee

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SteveNet
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Re: Another water heater query - hybrid water heaters

Post by SteveNet » Thu Jun 19, 2014 1:11 pm

I have a Geyser water heater heat pump for the past 4 years hooked up to my regular traditional electric water heater.
Sold by Nyle systems.

It is hooked up independent of the water heater , not a hybrid.
I chose this because if anything happened to either the hot water heater or the heat pump you only have to fix/replace the one that is broken.
It plugs into a regular 110v outlet so you do not need an electrician for power.
It dehumidifies and cools my basement while heating my hot water in a 50 gal tank.
I have the circuit breaker turned OFF to the water heater, it's never on, the heatpump cooks all my hot water alone.
If anything happened to the heat pump, I would just turn on the circuit breaker and still have hot water via the Elec elements in the water heater.
It will heat the hot water to 140 deg... plenty hot. Edit, the temp is adjustable.

I have hooked up a killowatt meter to the heat pump and in a yr the heat pump cost me about $145 per year to cook my hot water vs around 500 for a traditional elec hot water heater.
So $350 per year savings times my 4 yrs or ownership $1400 saved so far. Not to mention I don't need my dehumidifier any more so add that as savings as well.

I also have a desuperheater connected via my geothermal ac/heating unit... it is useless. It only cooks hot water when the geothermal unit is running, not on demand for hot water.
The geothermal unit is so efficient that the head pressure heat never gets above 115, so the hot water in the hot water tank never gets above about 105 IF the geothermal is running.
I have since disconnected it. It was free with my geothermal unit as the one with the desuperheater was the only on in stock at the time so no loss.

I highly recommend the Geyser for hot water heating, if you have the room for it and in a unconditioned space, so it doesn't rob you of your heat or ac.
Being frugal is hard to learn, but once learned is hard to stop.

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Re: Another water heater query - hybrid water heaters

Post by Valuethinker » Thu Jun 19, 2014 1:36 pm

4nursebee wrote:Instantaneous water heaters are likely much more efficient than anything mentioned here, I recall >85% effiecient either gas or electric. My Rinnai has needed no upkeep, > 10 years.

Keeping "X" gallons of water hot all the time is inherently less efficient.
Any idea how an electric one works? Because to heat water 'on demand' you need a lot of heat. My neighbour (4-5 bedroom house, 2 kids) has a on demand system that puts out 30KW (1kwhr = 3666 BTU) from gas.

Now UK systems are 'indirect' the boiler heats both the hot water *and* the rads. My boiler (also 30KW at peak output) fills a tank (with 6" of plastic foam on it and insulated feet) that holds the heat for days. Now from what I understand from here (Epsilon Delta's posts) the US system you get more heat going straight up the flu, so the insulated tank just doesn't work as well-- at least that's what I understood the issue is in most US systems.

But to heat a significant amount of water electrically on demand (and your household voltage is 110 V?) you are going to have a really serious KWs. Is there a problem with the house wiring?

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Re: Another water heater query - hybrid water heaters

Post by BrandonBogle » Thu Jun 19, 2014 1:41 pm

I like this thread and always willing to consider non-traditional solutions. My mother's house in Miami may benefit from this discussion around desuperheaters. Her a/c is always running and she would love to stop using propane gas at the house. However, there would be no room for any additional equipment in the utilities room (with the washer/dryer) if the unti has parts there.

At my own house, my electric water heater was installed in 2006 (before I bought the house). I feel it is quite effective, but most of this is in the house design and insulation. The basement is has a heat pump system for cooling/heating the house, with no venting in the basement. The basement is at comfortable temperatures with 50% humidity roughly 85%-90% of the year. The dead of winter and summer provide some extremes, but nothing you cannot easily handle.

I would imagine that having a heat pump a/c would negate having a hybrid water heater since it is "using up" the higher heat and humidity of the basement during the whole house cooling/heating?

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Re: Another water heater query - hybrid water heaters

Post by wageoghe » Thu Jun 19, 2014 1:53 pm

SteveNet wrote:I have a Geyser water heater heat pump for the past 4 years hooked up to my regular traditional electric water heater.
Sold by Nyle systems.
I saw this on Ask This Old House recently. It looks very cool. It does require an ambient temp of 50 degrees (manufacturer recommends turning off otherwise). In our case, our water heater is in the garage. In our area the average low temp is 50 or lower from mid-October to mid-April, while the average high is 50 or higher almost the entire year. That would mean going with the water heater's resistance heat during that time (Since the manufacturer recommends turning the Nyle unit off in those conditions. Too bad the Nyle doesn't have more sophisticated control circuitry to allow it to turn itself off during suboptimal temps. With a hybrid I think that it will automatically switch from heat pump to resistance heat automatically, as needed. So, during that time period, a good amount of hot water could still be generated via the heat pump.

Anyway, thanks for posting about the Nyle. It looks like a great solution in the right application.

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SteveNet
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Re: Another water heater query - hybrid water heaters

Post by SteveNet » Thu Jun 19, 2014 3:06 pm

BrandonBogle wrote:I like this thread and always willing to consider non-traditional solutions. My mother's house in Miami may benefit from this discussion around desuperheaters. Her a/c is always running and she would love to stop using propane gas at the house. However, there would be no room for any additional equipment in the utilities room (with the washer/dryer) if the unti has parts there.

At my own house, my electric water heater was installed in 2006 (before I bought the house). I feel it is quite effective, but most of this is in the house design and insulation. The basement is has a heat pump system for cooling/heating the house, with no venting in the basement. The basement is at comfortable temperatures with 50% humidity roughly 85%-90% of the year. The dead of winter and summer provide some extremes, but nothing you cannot easily handle.

I would imagine that having a heat pump a/c would negate having a hybrid water heater since it is "using up" the higher heat and humidity of the basement during the whole house cooling/heating?
I am confused on your house setup.
You have a basement... Your Hot water heater is in the basement. Your Basement has no "conditioned" air such as heating or cooling?
You have a heatpump a/c in the basement? Do you mean you have a split unit? one unit outside the house with the 'air handler' inside the basement?
If that is the case that is how mine is set up, except with geothermal the inground wells are the outside unit so to speak. And the basement has no vents for heating or cooling.

"I would imagine that having a heat pump a/c would negate having a hybrid water heater since it is "using up" the higher heat and humidity of the basement during the whole house cooling/heating?"

You state you have no venting in the basement, do you mean no a/c or heat venting? Or outside moisture control venting?

If your basement is Heated or Air conditioned by a heatpump then having a heatpump for hot water inside the basement would be no good.
If your basement is NOT heated or Air conditioned by your house heatpump, then the water heater heat pump would use the heat in the air in the basement to heat the hot water.
De-humidification is a free benefit.
Being frugal is hard to learn, but once learned is hard to stop.

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SteveNet
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Re: Another water heater query - hybrid water heaters

Post by SteveNet » Thu Jun 19, 2014 3:13 pm

wageoghe wrote:
SteveNet wrote:I have a Geyser water heater heat pump for the past 4 years hooked up to my regular traditional electric water heater.
Sold by Nyle systems.
I saw this on Ask This Old House recently. It looks very cool. It does require an ambient temp of 50 degrees (manufacturer recommends turning off otherwise). In our case, our water heater is in the garage. In our area the average low temp is 50 or lower from mid-October to mid-April, while the average high is 50 or higher almost the entire year. That would mean going with the water heater's resistance heat during that time (Since the manufacturer recommends turning the Nyle unit off in those conditions. Too bad the Nyle doesn't have more sophisticated control circuitry to allow it to turn itself off during suboptimal temps. With a hybrid I think that it will automatically switch from heat pump to resistance heat automatically, as needed. So, during that time period, a good amount of hot water could still be generated via the heat pump.

Anyway, thanks for posting about the Nyle. It looks like a great solution in the right application.
Your welcome wageoghe, as for not using the Geyser during below 50 deg but above freezing during certain parts of the year, there is a on\off switch on the unit. when mid Oct comes just turn it off and rely on the electric water heater to heat the hw, then turn it back on again in mid April.
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BrandonBogle
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Re: Another water heater query - hybrid water heaters

Post by BrandonBogle » Thu Jun 19, 2014 3:52 pm

SteveNet,

Sorry for the confusion. This is not my fortay, so I will try to explain to the best of my ability. I have an air-sourced heat pump for cooling/heating of a two-story with a walk-out basement (essentially a 3-story). There is an inside unit in the center of a basement and an outside unit just outside its door. The inside unit's ducting runs upstairs with no duct exit points in the basement. I do have returns on the main and top level levels.

So even with the heat pump on, I have no active circulation in the basement from this unit. However, being an air-source HP, it does remove humidity from the basement and either the HP action or the general construction of the house (and my area) keep the basement comfortable enough to use as a play-room.

There are windows in the basement that typically remain closed (I haven't opened them once in 4 years yet). There is no outside ventilation in the basement unless a window (or the exterior door) is open. It does sound like we have the similar systems except mine is air rather than ground-sourced. Am I perhaps mistaken in the role of the inside unit? I thought it not only provided air-handling, but also dehumidified and affected the air inside the basement since it provides the differential compared to the air at the outside unit?

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SteveNet
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Re: Another water heater query - hybrid water heaters

Post by SteveNet » Thu Jun 19, 2014 4:22 pm

BrandonBogle wrote:SteveNet,

Sorry for the confusion. This is not my fortay, so I will try to explain to the best of my ability. I have an air-sourced heat pump for cooling/heating of a two-story with a walk-out basement (essentially a 3-story). There is an inside unit in the center of a basement and an outside unit just outside its door. The inside unit's ducting runs upstairs with no duct exit points in the basement. I do have returns on the main and top level levels.

So even with the heat pump on, I have no active circulation in the basement from this unit. However, being an air-source HP, it does remove humidity from the basement and either the HP action or the general construction of the house (and my area) keep the basement comfortable enough to use as a play-room.

There are windows in the basement that typically remain closed (I haven't opened them once in 4 years yet). There is no outside ventilation in the basement unless a window (or the exterior door) is open. It does sound like we have the similar systems except mine is air rather than ground-sourced. Am I perhaps mistaken in the role of the inside unit? I thought it not only provided air-handling, but also dehumidified and affected the air inside the basement since it provides the differential compared to the air at the outside unit?
Ok I have a good understanding of your layout now, short answer is 'Yes' you can have a Heatpump in your basement just for the Hot water heater.
As you do not condition the living space in the basement with a/c or heat, you will not 'rob' the house of heat.
Your in the basement unit is a air handler and it also has the cooling and heating coils in it as well but it is a closed system with the floors above the basement as there are no ducts providing conditioned air to the basement.
The unit in the basement 'does' provide de-humidification but only to the air going to the floors above the basement. The fact that is an air source HP does not mean it De-humidifies differently inside the home. vs an in the ground source.

So yes, it seems we have the same layout, and you would do well with a hot water heat pump in the basement. Just remember, as you use it as a play room the sound of the Geyser will be much like the sound of a window air conditioner but inside. Edit..when it's running that is.
Edit again... as the unit does remove humidity you have to have a way to dispose of the water, you already have the houses heatpump in the basement that discharges it's water to either a drain or a condensate pump, you can have the hw heat pump drain to either of those as well.
Being frugal is hard to learn, but once learned is hard to stop.

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BrandonBogle
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Re: Another water heater query - hybrid water heaters

Post by BrandonBogle » Thu Jun 19, 2014 6:09 pm

Yes, we have a drain pipe for the house's heat pump and an automatic dehumidifier that that kicks in whenever the humidity level gets about 65% (when the dryer is running basically). The house is all electric and only an average of $120/mo (summer) - $160/mo (winter). But Mom's house is where I can see this really paying off, though some of that would simply be around getting her off a propane water heater to a hybrid or electric one. After that, we can replace her stovetop and close out her propane service altogether. For my house, I will keep that a hybrid in mind whenever it comes times to replace the current unit (no time soon I hope).

Thanks Steve for teaching me a bit! :)

Valuethinker
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Re: Another water heater query - hybrid water heaters

Post by Valuethinker » Fri Jun 20, 2014 5:18 am

BrandonBogle wrote:Yes, we have a drain pipe for the house's heat pump and an automatic dehumidifier that that kicks in whenever the humidity level gets about 65% (when the dryer is running basically). The house is all electric and only an average of $120/mo (summer) - $160/mo (winter). But Mom's house is where I can see this really paying off, though some of that would simply be around getting her off a propane water heater to a hybrid or electric one. After that, we can replace her stovetop and close out her propane service altogether. For my house, I will keep that a hybrid in mind whenever it comes times to replace the current unit (no time soon I hope).

Thanks Steve for teaching me a bit! :)
One issue in Florida is very high electricity prices? I think?

However if there is a time of day tariff then if you have hot water tank (ie not tankless) you can work around that.

Any possibility of venting the dryer outside? (I wonder if the dryer would then have to work harder, due to nearly 100% relative humidity in summer months?)

Propane seems to be priced off the oil price not the natural gas price (my vague understanding is that it is partly a byproduct of oil refining OR because it competes with oil as a home heating fuel) and so is quite expensive per unit of energy (plus all the other issues re refill and safety).

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deanbrew
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Re: Another water heater query - hybrid water heaters

Post by deanbrew » Fri Jun 20, 2014 5:36 am

Valuethinker wrote:Propane seems to be priced off the oil price not the natural gas price (my vague understanding is that it is partly a byproduct of oil refining OR because it competes with oil as a home heating fuel) and so is quite expensive per unit of energy (plus all the other issues re refill and safety).
Propane is a petroleum product, and does not come from natural gas, so the price is in line with heating oil, or about two to three times as expensive as natural gas in most areas. If you heat your water with electricity, then a heat pump water heater can definitely make sense. Make sure to check with your utility company - mine sent me a $300 check when I bought my hybrid water heater earlier this year.
"The course of history shows that as the government grows, liberty decreases." Thomas Jefferson

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BrandonBogle
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Re: Another water heater query - hybrid water heaters

Post by BrandonBogle » Fri Jun 20, 2014 8:44 am

At mom's house in Florida, the utility room is actually outside. You walk out the back door and go around a corner into the utility room. The washer, dryer, and water heater are in there. The outside end of her a/c is right outside this door too. The dryer does vent to the outside.

Because mom lives alone in a small house, her gas bill is rounded up to the "minimum charge" almost every month. With the service fees, that puts her around $45/month for very little usage. In her scenario, the electric hit (even with Florida's higher rate) is worthwhile to make the switch at next failure. The big thing is getting an electrician out. I don't know about her gas water heater, but her gas dryer is using 110. Note, the dryer no longer heats properly. She uses it on air only to spin dry her clothes. She is waiting to make the "big switch" to 220 for other reasons and we would change the dryer out too then. I didn't include that since she seems perfectly fine with using the equivalent of a line dry for two years now, so I doubt it would be a problem (for her) to continue that.

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