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simmtalker

Heat Pump Water heater for Central PA

simmtalker
5 years ago
Does anyone have experience/opinions about using a hybrid heat pump water heater in central PA or similar area?? I realize it might not work well, as a heat pump, in the cold months, but if it would do its thing in the warm months, I think it could easily pay for itself. Also, I'll be using more hot water in the summer than winter, which would be even better. It would be in a basement, slightly smaller than 36'x28'. Basement has a drain, and a Bilco door (thinking of allow more warm air into the basement in warm months).

I was looking at the AO Smith 66 gallon version. Is this brand reliable?? Doing the math, I am planning on a 10 year life, but the company says 12-15 years, so I think I am figuring conservatively.

One more question.... Is there such a thing as a desuperheater for an air source split heat pump system? (hope I am using the right terms). They are used often with the ground source systems, but I can't find much info about air.

Comments (45)

  • _sophiewheeler
    5 years ago

    With the availability and low cost of NG there, I’d do a NG tankless and not look back. NG furnace, cooking, dryer, fireplace and whatever else you need heated.

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  • simmtalker
    Original Author
    5 years ago

    Springtime, thank you very much for the post and information!!

    Sophie - I live out in the country, no NG.....heck, we don't even have cable TV, yet!! Very primitive living :)

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    "Natural gas? Burning fuels inside is unsafe, threatens health and is usually not cost-effective if building new."

    More baloney, as in the other thread.

    Natural gas is the cheapest way to heat water, just for starters. In many areas, it's the cheapest way to heat a structure. And it's as safe as could be.

    In much of the US, electricity is produced by burning coal It's 30% of the total. Electrical HVAC units are a worse choice, not a better choice, if using coal-produced electricity. Natural gas, whether used in a power plant or in the home, is a much safer and less risky fuel from a human health standpoint.

  • geoffrey_b
    5 years ago

    @Springtime Builders : Burning fuels inside is unsafe, threatens health and is usually not cost-effective if building new.

    This is rubbish. I grew up in the NE - most everyone heats with gas. I'm here in Minneapolis - everyone uses gas. Natural gas is abundant - and it doesn't fail when the electricity goes out.

    Maybe you don't know how to build houses.

  • oneandonlybobjones
    5 years ago

    The AO Smith manual says it operates in heat pump mode down to 45 degrees F. The Rheem hybrid heat pump water heater that Home Depot sells says the heat pump operates down to 37 degrees. If they both are the same price then I'd go with the Rheem since it operates in heat pump mode down to a lower temperature. The other thing you should check is how long the anode rods are projected to last in both units since those need to be replaced at some point.

  • PRO
    Springtime Builders
    5 years ago
    last modified: 5 years ago

    There can't be many utility markets where a gas water heater costs less to operate than a 3.39 EF Steibel Eltron or 3.7 UEF 80g Rheem Prestige. High efficiency air source heat pumps combined with international code building envelopes are also cost competitive with gas even in cold climates. In new construction, all-electric is arguably more affordable than gas anything.

    Lack of distinction between atmospherically vented combustion appliances and direct vent should give caution to those following safety advice from above combustion appliance opinions.

    If you don't notice the transition away from combustion appliances you're not paying attention or doing enough research. It reminds me of Martin Holladay's recent article Where to Find Good Advice, unfortunately behind paywall. I agree with his recommended resources like Building Science Corporation. For trustworthy magazines: Fine Homebuilding, Journal of Light Construction and Home Energy Performance. I read most cover to cover and full disclosure; some of my articles and homes have been featured there.

    We have built some of the tightest homes in the Southeast and understand the physics of air movement in homes. I've seen plenty of "leaky" existing homes with gas appliances showing evidence of backdrafting, exposing occupants to low level CO. It's an important life-safety issue and why code departments are finally beginning to enforce make-up air requirements. Now that all-electric is cost competitive, there is little reason to introduce combustion exhaust as a source of pollution inside a home.

    I agree with bobjones about longevity which is why I bought the only tank water heater with no need for anode rod, ten years ago. I would still choose the electric tank Rheem Marathon over any gas model as it sets me up for utility incentives or excess storage arrangements paring well with exploding renewable electricity market. The Steibel Eltron's HPWH rod has above average engineering and Rheem advertises the Prestige's as "premium".

  • sis33
    5 years ago

    Not wishing to hijack this thread but trying to understand the subject of efficient water heating along with water conservation (we are in Florida). In our case the hot water would have to travel approximately 100 feet from the heat pump water heater in the garage to the master bath. Would there be a significant waste of water (and time) due to us having to wait for the hot water to travel to the master bath? I see that Steibel advises against a recirculating loop.

    Count us among those new home builders who wish to eliminate combustion exhaust from our homes. We are hoping that we don't have to resort to a propane gas tankless water heater for our master bath.

  • PRO
    Charles Ross Homes
    5 years ago

    To be sure, proper indoor air quality/ventilation are important considerations in today's "tight" houses. The high-efficiency gas furnaces and tankless hot water heaters that I'm familiar with are sealed combustion units; they use outdoor air for combustion. I don't see how they would cause or contribute to a backdraft condition.

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    Springtime Builders, did you decide to sidestep the coal-produced electricity issue? That's usually the source of power in areas where it's cheap.

    Your building engineering citation, regarding combustion equipment within the building envelope, is specious, because that's rarely where they are. I have two furnaces, two water heaters, in a 30 year old house, none are within the envelope nor in an attic, crawl space or basement. Properly installed in a proper location, there are no backdrafting or CO issues (except for a cracked heat exchanger). Why continue with stretching the truth to falsely scare monger?

    I looked up the 80 gal rheem model you cited. My plumber has recommended a couple of different brands for an upcoming replacement of a gas heater and rheem isn't one of them but that aside, the company spec sheet says it uses around 1350 kwh per year of electricity. I found it odd because it didn't say how much water that would be heating. But just taking that number for a moment and using my own electricity rate of nearly 30 cents per kwh, that would represent a cost almost double what I pay with gas heaters. Gas is high where I am along with electricity and in a lower cost area, it might be an even greater multiple than 2 x.

  • jrb451
    5 years ago

    FWIW, We have a GeoSpring heat pump water heater. The manual states that it will work in the heat pump mode down to 45 degrees but it doesn’t. I have to switch over to “hybrid” (heat pump & electric elements) around 50 degrees. Still, not bad. I’d buy it again.

  • David Cary
    5 years ago
    last modified: 5 years ago

    How many basements get to 45 degrees? On new construction? That I would consider a bigger issue.

    I have a heat pump hot water heater. We bought current house as a resale and haven't been here long enough to comment on longevity. It works great. No issues - in the garage. Doesn't run that often.

    Elmer - the vast majority of the country does not pay $.30 and so that isn't a great comparison. Look at the trajectory for coal use in the US and the longevity of a new house. In Texas where some plans have free electricity at night - excess wind. Look at areas where hydropower is big - Washington state for one.

    The economics of electricity are interesting. Wholesale is about 4 cents. Coal, NG, solar, wind all play in the 3-6 cent range. So while what you are saying is generally true - that coal plays a role in cheaper markets - it really isn't because of costs. NG has been cheaper than coal in most markets for many years now. Coal is just so nasty that it wasn't used as often near dense populations and dense populations have greater distribution costs and regulations. Coal will not survive very long despite the current administration.

    OP is in central PA. Presumably a relatively cheap electric market. Their alternative is Propane. It would be very wise to use a heat pump hot water heater. In fact, it would be rather unwise to use anything else - except perhaps solar.

    Springtime isn't necessarily talking about exploding houses or CO poisoning by NG - although those things do happen - but more the health effects of the products of consumption. The risks are higher with modern tight houses.

  • Elmer J Fudd
    5 years ago

    Wholesale prices for electricity are currently low and vary daily but that has little effect on a household's bills because the power companies enter into long term purchase contracts at fixed prices. In my particular case, the actual electricity cost is less than half of the retail cost per kwh. But prices are rising because California has mandated ever increasing percentage targets from "renewable" sources and the new projects being built produce more costly power than existing ones. I think the mandated source switch-over is a good thing but it comes with a cost. Wind blowing at night in Texas is great but did you know that the Texas grid - ERCOT- is mostly not connected externally to others?


    There are many areas, not just mine, where electricity is expensive and not the better choice for heating anything when natural gas is available The Northeast is another such area.


    All of that is neither here nor there and ultimately off-topic. My comments had to do with the broad generalizations that had been made that I thought were incorrect and I said why.

  • PRO
    Springtime Builders
    5 years ago
    last modified: 5 years ago

    Electricity at 30 cents kwh is Hawaii pricing and I don't think NG is available there. New England doesn't get much higher than 20 cents. The high EF heat pump water heaters I referenced, should be cheaper to operate.

    Funny to be questioned on coal sourced electricity as experiencing it's effects on an Appalachian Trail thru hike out of high school is what inspired me to choose a career in energy efficiency. When I was in college majoring in appropriate technology and construction technology, affordable Photovoltaics was a pipe dream. Now, smarter analysts than me point out PV and wind are the most affordable sources of electricity.

    PV and wind are coming on so strong that storage has become one of the biggest concerns. Electric vehicles and electric tank water heaters are two solutions to this problem. Electric utilities are increasingly offering incentives to store excess power generation in water heaters. This is a great way to lower costs and play an integral part of the increasingly renewable electric grid without investing in PV panels.

    There is no form or percentage of renewable gas. While it burns cleaner than coal, it requires fracking to extract. Gas extraction is increasingly recognized as a polluter of surface and ground water. By choosing or recommending gas, you could be contributing to contamination of another person's drinking water.

    At least with NG electricity generation, the combustion is not inside of the home. The high efficiency gas appliances that Charles Ross is familiar with (and we sometimes install) are pretty safe. However, I do not believe they are completely airtight or immune from backdrafting. Our energy rater, who is also a mechanical engineer, tells me that power or direct vent combustion appliances can backdraft at ~50 pascals of pressure.

    I can think of several scenarios where this much negative pressure is possible. The most likely is from an oversized cooktop venthood. A recent home of ours with a "sealed" tankless gas water heater will not operate when the venthood is on, even though it has a code-approved make-up air unit. The shut-off is a safety feature built into the appliance. This is annoying as it hampers the home's basic functionality but also highlights a health and safety concern. What happens when this safety feature fails? For that matter, all appliances eventually fail and combustion appliances carry the added health risks of CO poisoning.

    I agree with David but challenge idea of higher risk with modern, tight homes. Leaky houses backdraft too. I'm not aware of any research suggesting tight homes are more at risk than leaky ones. If a study did try to look at this, the current international code requirement of outdoor air ventilation might prove the modern tight houses have less CO, combustion appliances being equal.

    sis33, seems like a good place to ask though by starting a new thread with your plan would probably result in a more diverse response. A heat pump water heater in Florida is an easy choice as long as you can make space for it. Florida garages are a fine spot. Your main problem is lag time and while it's probably too late, try to do better next time by designing a compact plumbing footprint. I have an old blog on cost-effective water conservation though it needs updating. I haven't read Steibel Eltrons language on avoiding recirculation but it's probably mainly addressing continuous recirculation, and agree to not do that, no matter what kind of water heater. As some of the illustrations in that blog point out, configuring a recirculation loop that is controlled by a button or occupancy sensor would be my first suggestion. If that is not possible, a separate water heater might be the best choice.

    We have installed a few of the Geosprings and so far so good, but one homeowner doesn't like how loud it is. As David points out, 45 degree basement suggests a pretty major air-leakage problem. You might want to have a home performance contractor check things out or do some DIY air-sealing in the attic and basement.

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    Our weather is pretty darn nice here year round but it's not Hawaii. I said North East, not just New England, and I think your numbers are off.

    We have a great overhead cooktop vent and we know to crack a window in another room when using it. That's common sense.

    My combustion units are in air-tight closets isolated from the rest of the house and with floor and ceiling vents. Also some in a well ventilated (floor and rooftop vents) garage. These approaches are code compliant and typical in my area. Tell me what exposure I have and to what.

  • PRO
    Springtime Builders
    5 years ago
    last modified: 5 years ago

    You can find electricity rates by state here. That's great you seem to be aware of the dangers introduced by your combustion appliances and adjust your habits to better manage the risk. I find some homeowners are good at this while others are not. There is no guarantee the next owners will crack windows or keep certain doors shut to ensure a safe home.

  • mike_home
    5 years ago

    A new construction all electric home in the Northeast is not going to be popular with buyers. This is because electric rates are high and natural gas prices are low. Then you have some who want a commercial stove in their kitchen. If there are health issues burning gas then builders will have to figure out how to solve it.

    I would hate to have to pay the electric bill for an 80 gallon hot water heater. I personally don't see the need for all that hot water even if the electricity was cheap.

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    Springtime, If I didn't crack a window, the cooktop hood would all the same not cause a backdraft of a furnace or water heater. They're isolated from the house, as I described.

    You won't get off your phony "danger" horse and so be it. Is scaring potential customers with this and that your normal approach?

  • PRO
    Springtime Builders
    5 years ago
    last modified: 5 years ago

    I disagree about demand for all-electric homes. Smart buyers recognize all-electric homes are safer and can be cheaper to operate than gas when done well, even in high priced electric markets. All-electric homes are often featured in JLC and FHB as they focus on that region. Architects and builders versed in high efficiency building seem to have plenty of work in the current market.

    The building industry response to commercial gas stoves is make-up air and it's a less than perfect solution. I think people are beginning to recognize induction is better than gas in almost every metric and it's still a relatively new technology so hopefully the gas stove's days are numbered.

    Heat pump water heaters sip electricity at suprisingly low rates. Big storage tanks make sense for most families because they add heat slowly over time. If you don't need 80g, choose a smaller unit.

    Elmer, I'm not the only builder promoting all-electric homes. If backdrafting is not real or risky, why does code now require make-up air?

    Here's an article that outlines dangerous levels of measured pollutants from gas stoves, even with proper venthoods.

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    Housing is very expensive where I live and as everywhere, buyers and new site builders are picky. You think you know what's happening in my market and yet most of what you say hasn't been very insightful. All electric houses, heat pumps, etc., are dead on arrival in this area. Whether true or not, they're viewed as a sign of cheap construction. Gas appliances - the Gold Standard in this market where natural gas is available and in rural areas, often propane in its place.

    Tell me, where are you and why do you think you know so much about California housing?

    Also, how does a busy builder have time for a forum like this during weekday work hours? I'm retired, that's my excuse, are you too?

  • mike_home
    5 years ago

    If you know of any all electric new home developments in the northeast or mid-Atlantic states where natural gas is readily available then please post the information. If any are in driving distance of central NJ I would interested in visiting them.

    I am not familiar with heat pump hot water heaters because they don't seem to exist where I live. I would be interested in the the math in comparing the energy cost versus a gas fired tank model.

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    PS - I just looked at the article you linked. The findings were based on a model, not measurements. I hope you know the difference. A model is theoretical, the other is reality. Included was this sentence "A vent is a solution .."

    The "problem" isn't really a problem then, per your own source, if the equipment is used correctly. Isn't that the case with most anything?

  • jln333
    5 years ago

    Mike - I have a 80 gallon heat pump hot water heater. It is cheap to operate. The size of the storage tank is a tiny factor in the energy use. Typical modern electric 80 gallon standby is one the order of 20 kwh a month. Storage doesn't cost jack.

    All electric is the goal. Just because average consumer hasn't figured that out near central NJ doesn't mean it isn't right. You need to study green building a bit more.

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    As mentioned above, Rheem promotes its 80 gal unit as using 1350 kwh/year, which would be a bit over 110 kwh /month. I questioned that number because it doesn't speak to how much water is being heated but I'm willing to assume it's an average.

    Your 20 kwh/month figure isn't reasonable in light of that.

  • David Cary
    5 years ago

    Elmer - that number is presumably based on DOE usage - sort of like EPA gas mileage. I was talking about the storage number - or standby losses. Mike seemed to feel that an electric 80 gal hot water tank would be an energy hog. It isn't the size of the tank, it is the usage. Yes - size matters some - but usage is the real driver.

    People have an inflated idea how much storing hot water in a tank costs. This is driven somewhat by tankless manufacturers. But the difference is that a NG tank unit has significantly more standby losses than an electric tank.

    Modern code requires an EF of .95 for electric tank units. This means with average consumption (DOE), that 95% of the energy goes to usage since resistance elements are 100% efficient. This means 5% of energy use goes to standby losses.

    Using 5000 kwh as an average number for annual consumption, 5% of that is 250 kwh per year for standby losses. Really close to 20 per month. Note - last I checked, when you get a bigger tank they assume more usage. But that doesn't mean standby losses are significantly different.

    The only numbers I could find was a 50 gallon tank which listed an EF of .95 and 3419 annual usage (DOE) so the standby losses are closer to 15 kwh a month.

    I realize this has gone way OT. Hard to have threads out there were misconceptions are not cleared up.

    Modern house should have either NG tankless or Heat pump hot water heater. Propane anything is rarely a good idea. Solar hot water is hard to justify given that solar PV has gotten so much cheaper.

  • mike_home
    5 years ago

    I don't know what the standby loss is for an 80 gallon electric hot water heater, but I think it is approximately twice that of a 40 gallon model. You may argue the cost of the standby loss is small, but that is highly dependent on how much hot water you on a daily basis.

    The recovery rate of an electric hot water heater is about half of that of the same size gas hot water heater. That's why you see 60 and 80 electric models, and 40 and 50 gallon gas models. I have a 38 gallon Rheem fury with a 40,000 BTU gas input. That combined with low flow shower heads has worked well so far. I love the fact it can produce hot water during a power outage.

    Consumers can only buy houses that meet local zoning and codes, and generate a profit for builders. So I am not sure it is all in the consumers hands to figure out.

    If a builder could construct two identical houses for about the same price and show the all an electric house costs less to operate than the gas and electric combination, then I think consumers would buy them. It sounds like it has happened in other parts of the US, but so far not in central NJ.

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    "This means with average consumption (DOE), that 95% of the energy goes to usage since resistance elements are 100% efficient. This means 5% of energy use goes to standby losses"

    Source ?

    "Modern house should have either NG tankless or Heat pump hot water heater. "

    You too are looking at the universe as if it were the same as where you are. Neither of these approaches are good choices where I live - the water is very hard and tankless devices get clogged prematurely and need frequent cleanouts. I'm sure that's true in other areas too. My plumber recommends against them and said he's stopped installing them. Do you have better knowledge about my area than he does?

    As for electric heat pumps - much more expensive to operate than a standard gas heater with a tank.

  • just_janni
    5 years ago

    When you know better, you do better.

    -Maya Angelou

  • mtvhike
    5 years ago

    I'm a little confused about this discussion of heat pump domestic hot water heaters. Are these installed in the basement, extracting heat from the basement air, or from the outside? If from the outside, then they need to be rated for cold climates. I know there are cold climate mini-splits, but don't know of any such water heater. If they are extracting heat from basement air, then that air has to be heated some how (in the winter).

  • Elmer J Fudd
    5 years ago

    Not all knowledge is useful or always relevant. Sometimes, ideas that are thought by some to be knowledge, aren't knowledge at all.

    -Elmer Fudd

  • Elmer J Fudd
    5 years ago
    last modified: 5 years ago

    mtvhike, I think your question was covered by heat pump heater owners, oneandonly and others, higher up in the thread.

  • Jake The Wonderdog
    5 years ago
    last modified: 5 years ago

    So here's the deal: Springtime is constructing super-tight new construction houses and using all electric to avoid another utility as well as any issues with indoor air quality / venting. There's some merit in that -- but it also all goes together as a package deal. I don't agree with much of what he has to say outside of that model.

    For many existing construction situations where natural gas is an option, a sealed combustion condensing natural gas appliance is a great choice - based on operating costs, environmental and even equipment costs. Electric resistance heat/hot water is still the most expensive (perhaps other than propane) and the dirtiest for the environment as long as coal is a significant source of electrical power.

    I do like the heat-pump water heaters where there is a basement, garage or in the south. Based on their DOE tags, they have some of the lowest operating costs (YMMV).

    Renewables are about 17% of the electrical energy pie with Solar being just 1%. We have quite a ways to go before renewables are a significantly larger portion of the total energy picture. There has been a lot of backwards movement on that recently with tariffs on PV panels, coordinated legislative attacks on net metering at the state level and changes to tax code. Calling preserving coal burning power plants a national security issue is so bass-ackwards it's shocking. Not to mention the attacks on science in general and the denial of global climate change.

    Storage continues to be a problem and "domestic hot water storage" has a ton of holes in it at this time.

    As a transitional energy source, natural gas has a lot of promise for the next 30 or so years... which is within the lifespan of most of the gas appliances such as water heaters and furnaces that are being installed in existing construction. In other words, by the time it really does make sense to go all-electric because of coal being mostly out of the picture, it will be time to replace those appliances again anyway.

  • ionized_gw
    5 years ago

    I am curious about the OP's high hot water usage in the summer. Is there a hobby involved? I got interested in desuperheaters for residential HVAC systems about the time that Nyle Systems introduced what was, to me, the first residential HPWH. Nyletherm were add-on systems to existing freestanding tanks or, perhaps, an indirect tank. Too bad that option is not available anymore. Residential desuperheaters might be an option if you could find someone to design them into the system and maintain them. I suspect that a decade or two ago it might have been more possible than today. Modern residential systems, unless you get the most stupid, old fashioned types may be difficult to add modifications to. Newer systems monitor performance at multiple levels and adjust operation accordingly. Adding a desuperheater might be difficult from both a physical and programming standpoint. (How are you going to splice a desuperheater into an existing vapor or flash injection design and then manage it?) I expect it is somewhat like hot rodding a modern vehicle, but with fewer economies of scale. I might be all wrong about this so you should check around about the desuperheater idea. If I am right you'd need more than one thing to make it economic, a big home, unusually large hot water demands, and a refrigeration expert with an imagination and eager to try new things with little monetary reward.

    The OP has an average size basement in an area where the soil temperature is what in the 50s F? This is not Florida or the SE. Some calculations should reveal if a HPWH will work there. If the basement is not insulated from the rest of the living space, rather coupled to it, the HPWH will be sucking heat from the rest of the house in the heating season so you might as well heat the water directly with the same power source. Making the heat elsewhere and then moving it into the water tank is inefficient. In the summer, it can potentially add some needed cooling and dehumidification, but not so much if the basement is isolated from the living space. If it is not humid there is no point and it might get too cool to work well.

    There is a lot in the is thread that bothers me. I can sum up most of my objections by expressing that anecdotes revealing the weaknesses of gas combustion appliances that are poorly installed, poorly chosen, or installed in otherwise poorly-built homes are not a valid argument against gas combustion appliances. They are only an argument against gas combustion appliances poorly installed, poorly chosen, or installed otherwise poorly-built homes.

    My feeling is that tankless water heaters are a fad. They may go forward in a niche market and they may return when conditions change. They are too complex and too service intense especially in hard water situations. They have lots of moving parts. In the not their fault column, natural gas is so inexpensive right now that investment in any super efficient hot water heater is hard to make pay off. If you want a backdraft with a fireplace or more open combustion furnace or boiler, they are a good way to cause one since compared to a conventional natural draft or unsealed domestic water heater, they need a huge amount of air in a relatively short period. If fuel gets expensive, they may get a boost.

    What are the potential savings switching from a old-fashioned dumb tank, natural draft water heater to another type? Please correct my figures if they are significantly off. A dumb, but good quality gas water heater might cost 500 bucks. A gas instant water heater twice that at 1000 in approximate numbers. An Energy.gov calculator indicates a difference in lifetime energy usage that just about covers the appliance cost difference. Then there is the repair and maintenance costs since I seriously doubt the ability of the average homeowner to clear the calcium carbonate scale.

  • David Cary
    5 years ago
    last modified: 5 years ago

    Tankless water heaters a fad? They were common 10 years ago in my area. Transitional fuel source - that makes sense. Fad - probably not.

    Hard water concerns - overblown? Don't know. I don't live in an area with water softeners.

    Energy.gov - says $100 a year (saved on tankless vs tanked NG). Ionized - are you going with a 5 year life? Then I would agree with you. Energy.gov lists it as 20 years - and storage tanks at 10-15.

    Elmer - The primary market where NG beats HPWH is CA. Rooftop solar for the most part makes that go away. You pay the prices you do as a conservation method - it has little to do with costs. Once the regulators figure out their mistake in over encouraging NG, your NG prices may change.

    From yesterday:

    https://arstechnica.com/science/2018/06/study-us-oil-and-gas-methane-emissions-have-been-dramatically-underestimated/

  • simmtalker
    Original Author
    5 years ago

    bob jones - thank you for the post!! I took a long look at the Rheem, and they have great specs and an even better price. I almost went with them, because they are the better deal, but after great deliberation, I think I will try to decide between the Steibel Eltron and AO Smith.

    Glad you brought up the anode rods! In reading reviews, those seem to be the most complained about thing to do with AO Smith HPWHs. I'm guessing that has to do greatly with the type of water a person has, how quickly those anodes give out, but at least I know that going into it. Although I have never changed anodes, according the internet, it looks as though I could handle it, if these tanks aren't terrifically difficult to work on. The HVAC company does an equipment operations review with customers after installation, and, if I go with the AO Smith, I will be asking him about how I can check/replace the anodes.

    jrb451 -- Actual user feedback is great, thank you so much for posting!!

    OP is in central PA. Presumably a relatively cheap electric market.
    Their alternative is Propane. It would be very wise to use a heat pump
    hot water heater. In fact, it would be rather unwise to use anything
    else - except perhaps solar.

    I'm working than I should to be wise, but at least I am trying LOL!!! Thank you for this, makes me feel better going with a HPWH!!

    mtvhike -- The type of HPWH I would be getting, and most people talk about, are all-in-one units. In my case, I would be placing it in a basement. That being said, there are such things as a split heat pump water heater, but I know very little about them -- I think they are used far more in other countries, but that may be said about most HP technology. The HVAC company salesman said there are units that have desuperheater type use built into them, but it is not anything that can be added aftermarket.

    I am curious about the OP's high hot water usage in the summer. Is there a hobby involved?

    Yes! I have two large, four-legged children (some people call them "horses" **insert eye rolling here**). Most of my quality is spent with my four-legged kids is in the summer, and they do tend to create more cleaning needs than average children. So, that, in addition to more cooking/get togethers and other warm weather outdoor activities, I use more hot water in the summer.

    Everyone -- thank you for the posts and excellent information!! I cannot comment much on some of the topics in this thread, as I do not have enough knowledge to have an informed opinion, but from a homeowner's point of view, who was unexpectedly forced to make a lot of big decisions in a short amount of time, the newer electric options look great on paper! Whether or not they function as well in the real world, I'll have to let you know in a few years. But, at this point, it seems like a good decision (those words will be on my tomb stone LOL!!!).

  • PRO
    Springtime Builders
    5 years ago
    last modified: 5 years ago

    Assuming California ballpark utility rates of $1.25 per therm and 15.34 cents per kwh, a 3.7 UEF Heat Pump Water Heater is cheaper to operate, than any available gas model.

    I agree there are many situations that call for tankless gas but for most new construction, HPWH is now best choice. New designs can account for space requirements. Cold climates are the toughest fit, but think a good case can be made for them when incorporated into design.

    For existing replacements in temperate garages, large utility rooms and basements, HPWH should be the first choice. Just make sure the space matches the headroom and volume requirements.

    Some don't seem to make a distinction between high efficiency gas models that have fairly safe combustion venting and cheap gas models that are atmospherically or naturally vented. The only safe place for atmospherically vented models is strictly outside of the building envelope. Backdrafting so regularly, they should be illegal inside a home and someday will be.

    We do combustion appliances for clients that want them but will not do natural vented gas models inside the building envelope. They are a serious liability whether the home is tight or leaky.

    30 years NG transition seems about right but that's for utility scale generation. Burning it inside residential homes adds too much unnecessary risk. The backdrafting issues are not compatible with efficient construction. Especially now that heat pumps are cheaper to heat with than NG in most utility markets.

    ETA: I appear to be way off with current ballpark CA utility pricing. At 19 cents per kwh and $1 per therm, NG is cheaper to operate assuming high efficiency units. Sorry CA! That's ignoring monthly utility fees and reduced cooling loads which if included, could make HPWH the better investment. Agree with David that NG is artificially low there compared to electric and is likely to change soon.

    ETA 2: Digging deeper into average CA prices, 1.25 per therm may not be too far off. Lots of regional and yearly variances in that state. In San Fran's current market, the Prestige beats NG but in San Diego it does not. Let's just say it's competitive there, for now.. :)

  • jrb451
    5 years ago

    simmtalker - a little more info on my experience: my GeoSprings unit was installed in 2014. My electric company gave me a $350 check for my energy efficent purchase. I took $350 off my Federal taxes that year. According to the Energy Star ratings I’m saving $300+ yearly on my electric bill over standard electric HW heaters. I bought the HW heater on sale at Lowe’s for $1150. Do the math, it’s a $150 HW heater that saves me $300 + annually. Also, the Energy Star test was done with the heater in hybrid mode. You’re savings in heat pump mode will be greater.

  • SaltiDawg
    5 years ago

    " If they both are the same price then I'd go with the Rheem since it operates in heat pump mode down to a lower temperature."

    It's in the basement. Who cares about that spec? lol

    I have a 50 Gal GE Heat Pump in my basement here in MD. Basement is below ground, about 1000 Sq ft. The heat pump at best removes a few pints of water per day from the air in the summer. It has NEVER had a measurable or noticeable effect on basement temperature. Six years old, saved me a fortune compared to resistive heater... no NG, no Propane.

    For the guy that installs it on his carport in FL, he have real concerns about efficiency with high outside temps - I've not bothered to do the math.


  • PRO
    Springtime Builders
    5 years ago
    last modified: 5 years ago

    HPWH do better with higher surrounding air temperature. The bigger concern is small, cold spaces. Cold air reduces efficiency while higher temps increase it.

  • Jake The Wonderdog
    5 years ago
    last modified: 5 years ago

    ionized_gw:

    You raise some issues... but I disagree.

    You are right that gas tank heaters are cheap to buy and that the payback is not all that great with a gas tankless.

    What I see is that a condensing gas tankless heater using PVC to vent solves a lot of problems, including the cost of venting the standard tank. It also solves the issue of the significant amount of air infiltration/exfiltration that comes from a standard gas tank water heater. (You have a 4" hole to the sky open in your house all the time acting as a chimney).

    I can't tell you how many gas tank water heaters I've seen with serious venting issues (back drafting, perforated vent pipe, venting into an unlined chimney, etc).

    The tankless heaters I've had have been very reliable. I also see them outlasting a tank heater.

    That said, with hard water a tankless heater is going to need cleaning. You can do it yourself or you can get a water softener. The good news is that you can effectively clean it, unlike a tank heater. A water softener would be cheaper than paying someone to clean your tankless yearly. The other benefits of soft water make it a no-brainer in my mind.

    A heat pump water heater is also a good choice if you have a basement, the water heater located in a warm garage, or live in the south or if you don't have natural gas. The payback on those compared to a electric resistance tank heater (or propane anything) is big... esp if there are tax incentives and utility rebates.

    I hate to say it, but the 65% efficient cheap gas tank water heater needs to go away - just like the 65% furnace did. As long as there is this super-cheap-to-buy option it will always be a struggle to get people to do something better.

  • SaltiDawg
    5 years ago

    "HPWH do better with higher surrounding air temperature. The bigger
    concern is small, cold spaces. Cold air reduces efficiency while higher
    temps increase it."

    Doh. For the range of temperatures found in a conditioned basement, the COP is just fine over the entire range.

    Your comment is similar to pointing out that a home Heat Pump Heating System will "do better" if the outside temperatures are in the eighties. So what?

    Read Jake The Wonderdog's post.

  • PRO
    Springtime Builders
    5 years ago
    last modified: 5 years ago

    "..he have real concerns about efficiency with high outside temps"

    Salti, I took your comment as doubting the performance of HPWH in warm outside temperatures, like those of a FL carport. Was hoping to make clear that's a good spot, if safe from sub freezing winter temps, doh.

  • simmtalker
    Original Author
    5 years ago

    jrb451 and SaltiDawg -- I hope my experiences are as good as yours -- if so, I will be a very happy camper!! I decided to go ahead with the 66 gallon AO Smith HPWH. The HVAC company from whom I am buying the Mitsubishi HP carries the AO Smith units, but charged a good bit more than Lowe's. Lowe's only carries the 50 and 80 gallon sizes, so I talked with the HVAC salesman about the price difference, and he offered to take $200 off the 66 gallon unit, which I am very happy with that price.

    Everyone -- Thank you so much for all the posts and information helping me to make this decision. I appreciate your time and efforts!!!!!

  • ionized_gw
    5 years ago

    Please let us know how it works out.

  • simmtalker
    Original Author
    5 years ago

    Will do!!!