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still thinking about new water heater - gas or hybrid??

KoanKoan Posts: 413Member
Tying to compare a hybrid heat-pump type water heater to a condensing gas tank type water heater, particularly with respect to efficiency. the Heat-pump type has a $500 BGE rebate, and installation would be far easier.

Looking at a Rheem XE80T10HD50U1 (EF 3.7) or 80 Gallon Accelera 300 E Residential Heat Pump Water Heater
from Stiebel Eltron (EF 3.39 Vs a gas unit (condensing?)

i do not know which if the heat -pump type is more efficient than condensing gas, and which is less expensive to operate. The benefit of the heat pump hybrid is that I can place the HWH next to the behemoth furnace in the basement drawing some heat from the metal run of the furnace flue. Condensing gas I would have to relocate and have to run a new vent and breather.

Have an undersized 40 gal normal gas tank heater installed in 2008. Even with water saving shower heads we cannot get two consecutive showers. At some point I will have to replace, but may wait until failure,

I asked here on the forum before about condensing gas tank type vs tank-less. Naturally the puppet movie was shared - It is funny I have to admit.

https://forum.heatinghelp.com/discussion/157853/age-old-question-tank-vs-tankless#latest

Here is the rub - a tank-less heater will require me to change my gas meter thanks to my IMMENSELY over sized 1969 American Standard boiler rated for 750 EDR with 400 EDR of radiator surface area. We have a gas dryer (22 k BTU), gas water heater (40 k BTU), and a gas cook top (50 k BTU) in addition to the gas boiler (300k BTU). This totals 412 k BTU on a 415 CCF gas meter. I have thoroughly cleaned the boiler and I am working on a solenoid on the vent to create natural vacuum and process controller to increase efficiency and prevent cycling on pressure (usually only happens when trying to raise temp too much). I see no reason to replace the boiler unless it shows some sign of failure.

Putting in a tank-less therefore means a new bigger meter. I would prefer not to have to pay BGE to do that, so I would not consider a tank-less unless the furnace has already been replaced.

thanks to the group for sharing your knowledge

Comments

  • Larry WeingartenLarry Weingarten Posts: 1,326Member
    Hello, This advice from 2016 is still good. "Take your shower heads and change them to 1.5 GPM shower head. There are many good shower heads that work great. You can put a tempering valve looks a cash Acme tank booster mixing valve on the water heater. Turn the water temp up as high as it goes to 150 deg or higher and mix cold water with the hot water and you will get more hot water out of your tank type water heater. "

    You can go with even lower flow shower heads. If you take tub baths, the dump load is big, so more storage makes sense. I'd lean towards a heat pump, but with an 80 gallon rather than smaller tank as it will operate in heat pump mode most if not all of the time. Research has shown that the bigger HP tanks are more energy efficient.

    Use energy cost as a surrogate for efficiency. Which fuel will cost you less? Also, I don't know just how long HP water heaters will last compared to condensing gas. Both are complex. In either, make sure to check the anode in the tank if it's a glass lined unit. That's a start ;)

    Yours, Larry
  • jacobsondjacobsond Posts: 19Member
    Why do you want to complicate water heating.Heat pump may be a new "great" thing, but $$$$$ with possible maintenance issues. Same with tankless $$$$$ with maintenance issues. Neither will likely last any longer than a basic tank heater. A well insulated tank and a coil or burner is simpler and trouble free. Myself I would get a bigger tank type.
    coming to you from warm and sunny ND
  • KoanKoan Posts: 413Member
    Thanks for the input gentlemen
    I was leaning toward an HTP Phoenix light duty Light, but saw the failure rate being way too high - in this case @jacobsond you seem to be right that sometimes simpler is better.

    @Larry Weingarten - we are already on-board with the shower heads. "Even with water saving shower heads we cannot get two consecutive showers."

    I agree with the 80- gal HP option if we go in that direction. I am one of the few that actually changes anode rods.

    I'll try to see what gas costs vs electricity.

    @jacobsond The simple answer to your question of why not a new tank is efficiency, ease of installation, and total value. The original post did not mention a height issue that exists for the flue. I can't use a unit any taller that the 40 gal one I have. Using a condensing gas solves that problem with a new "flue", but using a HP solves that problem and my behemoth furnace issue by moving to all electric.

    As far as lasting longer, I have already replaced the burner assembly as it failed. I think the HP units have a 10 year warranty. The existing unit seems to be too small and runs often.
  • Larry WeingartenLarry Weingarten Posts: 1,326Member
    Hello, Something seems out of whack with the "can't get two showers" bit. If your shower is a mix of 2/3 hot and 1/3 cold, that's one gpm of hot using a 1.5 gpm showerhead. The average length of a shower is eight minutes in the US. That would be 16 gallons for two showers. Your tank should deliver 75% of it's volume, or 30 gallons without cooling down. You should get nearly four showers from it! Either long showers are being taken or there is a problem, like a cross connection in the plumbing or damaged dip tube in the heater.

    Yours, Larry
  • ZmanZman Posts: 4,212Member
    @rick36
    rick36 said:

    Hi! Hybrid is definitely better

    Do you care to elaborate as to why you feel hybrid is better for this individual?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • JackJack Posts: 1,021Member
    The gas company charges for a gas meter change-out?
  • KoanKoan Posts: 413Member
    @rick36 and @Zman Yes, please do, if you don't mind, share your rationale for why the hybrid is better. I would appreciate learning from your experiences
  • KoanKoan Posts: 413Member
    @Jack I was told anything inside the house is my responsibility
  • jumperjumper Posts: 1,210Member
    Just buy a bigger conventional gas water heater. Nuts to energy savings. DHW is cheap so simplest is most practical.
  • Jamie HallJamie Hall Posts: 8,381Member
    Since we haven't heard back from @rick36 , I'll say a word or two... there are situations where hybrid is definitely superior: if you have limited electrical power and limited fuel (gas or oil), the efficiency with which they use electricity to produce hot water is a real plus. I know of one situation - a hotel on an island which has to generate all their own power and bring fuel in by boat -- which installed hybrids and made a real difference to the community.

    They're also useful in a situation where you need to cool the space in which the unit is located.

    That said... they're not cheap. The maintenance needs to be faithfully attended to. And they need to either have large tanks or have restricted water use, as recovery is slow -- unless they have auxiliary fuel or electric resistance elements. And in that case, why?
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • ZmanZman Posts: 4,212Member
    edited June 28
    If this was mine, I would not be considering tankless. The install cost is obviously higher as is the maintenance.

    That leaves you with hybrid or traditional gas heater. The traditional heater will produce more hot water. They usually produce around 32,000 Btu vs Hybrid at around 16,000 Btu. With 80 gallons of storage this may not be an issue.
    You have already figured out that there is no free heat with a hybrid but it sounds like your space has some heat to give up. Depending on your usage habits, you may never see the advertised 3.7 COP. With back to back showers, it will go into pure electric mode and give you a 1.0 COP for that period.

    At the end of the day, it will probably cost you the same to run a conventional tank heater as the hybrid. The tank model will require less maintenance and cost less up front. I would probably get one of those fancy new ones with the electronic ignition and damper to reduce heat loss. http://www.whirlpoolwaterheaters.com/learn-more/gas-water-heaters/6th-sense™/energy-efficient-gas-water-heaters/

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • GBartGBart Posts: 473Member
    If you're not getting enough hot water with 40gal gas fired WH YOU CAN FORGET A HEATPUMP OR HYBRID

    Check for first hour ratings and constant ratings, water heaters are rated by how many gallons per hour they can put out, a heat pump WH is only a more efficient electric unit, IT HAS NO REAL IMPROVEMENT ON SUPPLY OR RECOVERY or gallons per hour.
  • GBartGBart Posts: 473Member
    For example, average 40 gal gas WH, first hour rating 75g, recovery after 51GPH

    average 50 gal Hydrid, first hour rating 66 gallons, recover suspiciously NOT GIVEN but they tend to be as low as a standard electric which is below 10GPH
  • GBartGBart Posts: 473Member
    INDIRECT
  • GBartGBart Posts: 473Member
    edited July 10
    Go with an indirect, honestly you need an onsite evaluation, all you know at this point is that you don't have enough hot water, simply switching to a "more efficient" one means nothing other than you'll use less energy to still get not enough, yippee.

    Tankless is a viable option.

    You need to know your usage per hour and minute, the only way you're going to get what you need is with an indirect piped to your present boiler, then down the road get a new high efficiency boiler properly sized.

    For some comparison here are the ratings for Superstor Indirect water heaters.

    SSU-20 first hour-121 GPH SSU-30 first hour 154 GPH
    SSU-45 first hour 212 GPH


    http://www.htproducts.com/superstor-ultra-waterheater.html
  • GBartGBart Posts: 473Member
    edited July 10
    Take a 5 gallon bucket, measure the half way point and mark it, that's 2.5 gallons, run it in your shower and collect the water for 1 minute as you normally would have it set. That's your GPM, x 60 = GPH, do the other shower and see how they compare, if you shower at the same time you need that total.

    Now that you now your GPH and GPM, you can compare units for supply capability, if it's hard to find on a website they are hiding it because it isn't good, they will focus you on efficiency and savings, you need to have your GPH and GPM then pick out the most efficient unit that will supply that.
  • ChrisJChrisJ Posts: 8,969Member
    @Koan
    Was the 40 gallon heater always a problem?

    I ask, because a bad dip tube can make a good water heater seem like it always runs out of hot water.

    Our 50 gallon power vent can do two showers no problem. Of course there's a lot of variables. Length of shower, type of shower head, incoming water temp and the temp you run the heater at. My heater runs around 140-145, and plenty on here bash me for it.

    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • GBartGBart Posts: 473Member
    edited July 11
    Every water heater should run at 140 WITH A TEMPERING VALVE, 120F is the perfect breeding ground for bacteria and many respiratory issues, this video I made years ago explains it.

    Good point about the dip tube. An average gas fired WH puts out about 70GPH, but two showers running 2.5GPM each can out run it in 12-15 minutes.

  • JohnNYJohnNY Posts: 1,988Member

    hybrid heaters are more efficient than gas heaters.

    Boy, we throw that word "efficient" around very freely, don't we?
    For private consulting services, find John "JohnNY" Cataneo here at :
    "Heat Advisory, LLC"
    Or email John at [email protected]
    John is a professional Master Plumber by trade, licensed by The Department of Buildings of The City of New York, but travels regularly to out-of-state clients for consulting work.
  • KoanKoan Posts: 413Member
    @Gbart I think all the salient site info is here.
    @JohnNY I think this is what I was getting at. Which is more thermally efficient and which is more efficient from an amount of fuel used and cost of fuel needed

    the 40 gal heater has always been an issue. I know it was not maintained. I have flushed it and replaced the anode rod, and replaced the burner that died. I thought I checked the dip tube and it was fine. I suspect there is some sludge on the bottom I can't get out.

    Recently I changed the shower heads and that helped significantly. It is 10 years old though and within a few years I assume I will have to replace it. Even when turned to very hot it is not very hot. Maybe a dirty thermostat sensor?

    The hybrid solves my gas meter problem over a tankless
    I also have to be careful on height for a gas unit to to the flue, and the hybrid fixes that issue. the gas piping is a mess, street elbows and galvanized pipe to the HWH.

    The hybrid has the luxury of being next to a huge boiler in the winter.

    What i'd love to see is a hybrid with a gas backup - but I have not seen one.

  • GBartGBart Posts: 473Member
    You are going to get less hot water than you do now.

    Do the bucket test.
  • hot rodhot rod Posts: 8,419Member
    There were some HP type that were sold as separate components, the HP module could be added to any tank.

    The control logic to kick on the gas burner might be a challenge in a dual fuel HP tank.

    There were a few manufacturers that built solar (indirect) tanks with gas backup, but the market never really took off. Maybe a dual fuel HP with a gas burner would? Or build your own.

    Know that adding a burner, and a hole up through the center of the tank will cost some additional standby losses :) A power vent style might have more applications?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Jamie HallJamie Hall Posts: 8,381Member
    On thermal efficiency. If, and only if, the heat pump as a COP greater than 2.5, and if, and only if, you never ever run the electric resistance backup elements on it, it has a better thermal efficiency overall than a gas fired water heater. Otherwise, the gas heater is better in terms of fuel used per gallon of hot water produced and, if you are worried about carbon dioxide emissions, lower emissions.

    Unless, that is, your electric power is coming solely from a nuclear power plant or solar or wind power. (I am a little weird in that I don't count hydro -- the environmental damage from the dams is too great).
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • GBartGBart Posts: 473Member
    edited July 11
    You're all missing the main point, they are not going to have anywhere near the GPM or GPH of hot water unless they test.

    The unit they are looking at above is rated at Recovery Rate at 90F Rise (gallons/hour) - 98.

    But will it do the job?
  • ZmanZman Posts: 4,212Member
    What type of boiler do you have? I originally thought it was a furnace. I generally like indirects, if it is requiring you to fire a behemoth all summer, maybe not the best option.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,001Member
    Can we just get some numbers here? With all this "efficiency" jargon it's getting ridiculous.

    What is the cost of gas per therm, and the cost of electricity per kwh?
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • SteamheadSteamhead Posts: 12,220Member
    Zman said:

    What type of boiler do you have? I originally thought it was a furnace. I generally like indirects, if it is requiring you to fire a behemoth all summer, maybe not the best option.

    It's a huge, oversized American-Standard atmospheric feeding a Hoffman Vapor system. @Koan is one of our heating customers.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
  • ZmanZman Posts: 4,212Member

    Can we just get some numbers here? With all this "efficiency" jargon it's getting ridiculous.



    What is the cost of gas per therm, and the cost of electricity per kwh?

    Agreed, To really have this conversation, you need to know the actual DHW requirements and the local energy costs. I like @GBart idea for measuring. Once you have all the info it just comes down to what is costs to generate the energy needed.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • KoanKoan Posts: 413Member
    @Zman and @Solid_Fuel_Man

    In June we used 961kwh for a total cost of $124.15. The actual electricity only cost $74.76, the rest is taxes and BGE delivery charges but they are based on how many kWh used except for $8.26 in fixed customer charges. So the variable cost was $115.89 for 961kWh. Current electric cost is 7.642 cents per kWh and will increase to 7.810 cents per kWh in October.

    During the same period we used 28 therms of gas for a total of $40.84. The actual gas use charge was only $12.08. The rest is usage based delivery fees and taxes except for $15.00 fixed customer charges. So the variable cost was $25.84 for 28 therms. In January we used 516 therms most of which is for heat. An indirect would not make sense with the size of the boiler.

    We use gas for cooking and a gas dryer as well as DHW.
    The behemoth boiler is gas, but I shut off the pilot in the off season.

    I may just need to crank up the tstat a bit and insulate the pipes.

    @Steamhead

    Frank, you and Gordo are the best. You are true craftsmen and I suggest anyone with an old system like mine in the Maryland region should seek your counsel ether or not they think it necessary. Do you know how BGE addresses the potential need for a larger meter?
  • jumperjumper Posts: 1,210Member
    For anyone who really wants to drive themselves nuts here is something to think about. In the future electricity delivery charges may largely be flat rate as opposed to per kwhr. Energy part of electric bill may become less expensive. Smart meters are already installed so a large programmed tank water heater...
  • SteamheadSteamhead Posts: 12,220Member
    Koan said:

    @Steamhead

    Frank, you and Gordo are the best. You are true craftsmen and I suggest anyone with an old system like mine in the Maryland region should seek your counsel ether or not they think it necessary. Do you know how BGE addresses the potential need for a larger meter?

    With a lot of hassle and delay. I would avoid this if at all possible.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
  • KoanKoan Posts: 413Member
    @Steamhead

    Understood. Thanks
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