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MOD-CON... 18 Months Gas Usage Compared to Neighbors

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NY_Rob
NY_Rob Member Posts: 1,370
edited February 2018 in THE MAIN WALL
Have had the HTP UFT-80W in service for 18 months now, have some nice usage comparison graphs based on 100 similar size homes in my neighborhood over the last 1.5yrs.
Charts courtesy of National Grid based on actual (not estimated) meter readings...







BoonDZorokcoppnjtommyhydro_newbie

Comments

  • Zman
    Zman Member Posts: 7,573
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    Good stuff!
    What type of emitters do you have?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,541
    edited February 2018
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    So does the guy using 4 less therms have a better system? Or just freezing? :)
    To learn more about this professional, click here to visit their ad in Find A Contractor.
    Rich_49BoonnjtommyJohnNY
  • flat_twin
    flat_twin Member Posts: 350
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    That's great Rob. Usage after 6-26-16 looks quite different.
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    Zman said:

    Good stuff!
    What type of emitters do you have?

    The 1964 house was originally all std fin-tube, but due to low output at condensing temps I've add more where needed if possible. Where I couldn't add more I replaced the std fin-tube with Heating Edge 2, in one isolated zone I replaced the fin-tube with cast iron baseboard.

    Currently I'm using 135F SWT at 15F (Design Day Temp here).



    kcopp
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    So does the guy using 4 less therms have a better system? Or just freezing? :)

    I don't quite understand the "Efficient Neighbors" line, but I'm pretty darn close, so it's all good :)

    Robert O'Brien
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    flat_twin said:

    That's great Rob. Usage after 6-26-16 looks quite different.

    Yeah, I'm on the right side of the curve now!

    18 months later and I'm still amazed at the efficiency of the HTP Mod-Con. It can be 32F outside and my house is comfortable with 124F SWT. When it's running at it's 8K BTU minimum you have to look at the display for the flame symbol to see if it's actually firing.

    DZoro
  • Gordy
    Gordy Member Posts: 9,546
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    That’s a broad umbrella. Since you don’t know the usage patterns, appliances on grid, dwelling size, envelope construction, type of heat, number of occupants, or setpoint, setbacks of your neighbors.

  • NY_Rob
    NY_Rob Member Posts: 1,370
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    Thanks Gordy, I clicked on the "who are my neighbors link" and I got the popup below. In our area most of the 4-bedroom houses are similar size and construction and they are all nat. gas users.


  • ScottSecor
    ScottSecor Member Posts: 863
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    i got one for you guys. We also got those usage charts from out local gas company for the first time ever a few weeks ago. I think I tossed it, but my usage was higher than most of my neighbors for the last twelve months.

    I think I can explain, we've expanded the house three times over the years (was roughly 1400 sqft cape, now roughly double that. Our family of four grows to six or seven when the boyfriends/girlfriends and mother come every weekend and/or holidays. The house was under construction (no insulation in addition for approximately three months of the heating season).

    What I'm getting at is i suspect NY Rob's information and data are real world. His neighbors maybe or maybe not. Mine should get better starting next weekend when I finally finish the new heating and dhw system. Someday when it's just my wife and I, all of the utility cost will likely drop significantly.
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    Here's the 12 months from Feb 2015 to Jan 2016 with my old cast iron boiler where I was about even with the "All Neighbors" usage compared to the last 12 months with the Mod-Con where I pretty much match the "Efficient" neighbors usage.

    Before Mod-Con



    After Mod-Con






    danFromNJ
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    There are so many variable involved in this, that it is impossible to come to a definitive conclusion. The only thing is a comparison of the Therms uses monthly with the old system as compared to the new system. But...be aware last winter isn't the same as this winter so your need for nat gas can be different.
    Gordy
  • nicholas bonham-carter
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    At least the gas company is putting out some figures which anyone interested can study, and apparently compare useage with the neighbors.
    I wonder if some of the apartment buildings with badly maintained systems (7 psi!) will look at those graphs.—NBC
    NY_Rob
  • JUGHNE
    JUGHNE Member Posts: 11,075
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    So does the term "all neighbors" include the "efficient neighbors"
    in that average or just the neighbors with "non-efficient" systems for that typical house.
    What size of house are we looking at and what is your average total HDD?

    It seems the proper way to compare is to use HDD numbers and square feet/therm.
    My state has a web site with HDD and CDD updated by the middle of each month.

    I have a mod con doing 2300 sq feet on the first floor with 1700 basement. This is an average of 72 degrees. There is 1000 feet of attached unheated garage that might drop to 40-50.

    We have average of 7151 HDD.
    Dec 2017 was 1241 HDD......used 93 therms.
    Jan 2018 used 135 therms for a 33 day cycle. (No HDD yet).
    Highest most recent was Dec 2013 using 152 therms for 1451 HDD. That 2013-2014 season was 7611 total HDD.
    We use an average of 25 monthly for DHW and NG cooktop.
    IIRC the max SWT is 125 degrees.
    Built in 1995 with time consuming painstaking air infiltration prevention measures. More so than R-values.
    Passive solar that looks like a normal house.
    To complicated to figure out ROI. But very comfortable.
    It turned into a crusade/hobby of sorts.
    When we moved here from a house 1/3 this size our utility bills stayed the same.
    We go to our kids houses that have heat pumps and find it uncomfortable and noisy.

    I am curious to hear from someone with a new house to compare therms/square footage/HDD.
    Do you count a heated basement in with the total area?
  • NY_Rob
    NY_Rob Member Posts: 1,370
    edited February 2018
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    FWIW.... stats from the last couple of months with the Mod-Con.

    1964 2x4 construction, 1760 sq/ft, uninsulated/unheated quarter basement.

    107 therms used between Nov 30 - Dec 28 2017
    830 HHD between Nov 30 - Dec 28 2017

    165 therms between from Dec 29 - Jan 29 2018
    1132 HDD between from Dec 29 - Jan 29 2018
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,884
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    NY_Rob, nice work! I think the way I interpret this data is that you reduced your usage by what appears to be a solid 25%, assuming the average neighbors didn't change their habits too much. Moving from average to just outside the top 20% with an older house is impressive. That's the difference between making the playoffs and watching the playoffs from home.

    This is an interesting data point on real world vs. AFUE ratings and whether a cast iron boiler's AFUE should be compared directly to a mod-con's AFUE. I assume your old cast iron boiler had an AFUE of ~80%. Since your savings are ~25% when a 95% AFUE rated boiler replaces the old one, this data suggests that the 80% AFUE rating was unrealistically high and this measure doesn't seem to reflect as-installed reality consistently for cast-iron boilers, due to some combination of oversizing, performance degradation, etc.
    NY_RobSolid_Fuel_Man
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,616
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    @NY_Rob , nice job. I guess you could analyze the #s for ever. Looks like your saving a solid 20-25%.
  • NY_Rob
    NY_Rob Member Posts: 1,370
    edited February 2018
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    ^ Thanks @Hot_water_fan ..

    I was planning to replace the original 1964 boiler with another cast iron atmospheric. But, after considering the fact that in addition to all the other costs- I would need a $1K chimney liner to use another atmospheric boiler it tilted the scale towards a Mod-Con. I also liked the safety features the Mod-Con offered over atmospheric boilers.
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    @NY_Rob , nice job. I guess you could analyze the #s for ever. Looks like your saving a solid 20-25%.

    With the help of one of the contractors here, we came up with a 22% savings (for a high usage month) overall on gas when accounting for HDD, etc..

    Full disclosure- I did have to add radiation in some rooms and replace std fin-tube with low temp baseboard and cast iron radiators in other areas to bring the house up to comfortable levels using 115-130F CH water.

    I don't think someone going straight from a cast iron atmospheric with 180F SWT to a Mod-Con with 130F SWT would see the same savings without sacrificing comfort or adding/upgrading radiation.


  • Sal Santamaura
    Sal Santamaura Member Posts: 529
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    That comparison software has recently been put into use (and mailings sent out) by utilities across the country. Having installed 'smart meters,' they decided to show off their data. :)

    The only thing these graphs really convey is how much energy (gas, electric) one consumes compared to others nearby. There's no way for the utility to determine real efficiency. 'Single family homes' can cover a wide range of sizes, construction/insulation details, even types of heating systems, irrespective of how many people occupy them.

    The lines on those graphs ought be labeled "you," "average consumption" and "low consumption."
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,616
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    @NY_Rob agree. We just did a commercial job and are stuck using the existing emitters. Were running the boiler at about 134 return and 160 supply. (can't get enough heat if we lower the temp).

    134 return is making condensate but not a ton of it. So I think your absolutely correct to get the maximum efficiency the return water temp must be as low as possible
    NY_Rob
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    The only thing these graphs really convey is how much energy (gas, electric) one consumes compared to others nearby.

    Agreed, and they are actually useful in our area because we live in a typical 1960's era "Development" where there were only three basic "styles" of homes to choose from, they are all 4-bedroom design and all are approximately the same square footage.
    So in our case, there are literally 100's of "similar" homes within a couple of square miles of us.

    What's more important for the pro's here to note...
    Over the last year or so- I've seen four boilers replaced (that I know of) between the street behind us, our street and the street to the east of us. Two homeowners replaced cast iron boilers with cast iron boilers, two replaced cast iron boilers with Mod-Cons.

    Is the tide starting to turn?

    Robert O'Brien
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    EBEBRATT-Ed, This is something I have thought about for a long time. As experts, you guys may be able to help me understand it.
    As my high school science teacher said about experts, "X in mathematics is 'unknown' and a spurt is a drip under pressure."

    Mod/Con theory is that the cold return water lowers the dew point and the water vapour liquefies as a condensate. Thereby extracting heat energy out of the exhaust gases leading to 'improved efficiency'.

    Mod/Cons are a catagory IV appliance getting its combustion air from outside and sending the exhaust outside. This is what bothers me. If the outside temperature is 10 deg, you are sucking 10 deg air into the combustion chamber. That's going to lower the dew point. The colder the combustion air the more condensate is going to form and the stack temperature is going to drop. You get a lot more condensate in the winter than in the spring or fall when the combustion air is warmer.

    My thinking is that the real economic advantage to a Mod/Con is the turn down ratio and outdoor reset and that's where the real fuel saving happens. Help me out here.
  • Gordy
    Gordy Member Posts: 9,546
    edited February 2018
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    I don’t disagree more benefit comes from the TDR, ODR, and a control strategy some mod/cons offer to make it play nice with the system, than the condensing. However condensing adds some more efficiency. Depending on “return water temperature” not combustion air temp. I can not comment on combustion air temperature. What happens when it’s -30?










    NY_Robkalex1114
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    What is amazing to me is the fact that 8K BTU's can heat your house, even at freezing outdoor temps. 8K BTU's is the output of one of our stove top burners we use to make a pot of tea!
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
    edited February 2018
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    WOW! Super job, Gordy. I'm going to save all those graphs.

    I'm still wondering about the temperature of the combustion air. It surely must impact condensation and efficiency. Some those BTU's are going to raise the temperature of the combustion air. Also, I am wondering what was the temperature of the combustion air for those graphs.

    "What happens when it’s -30?" Ya! That what I want to know.

    Thanks for all the work.
    NY_Rob
  • Rich_49
    Rich_49 Member Posts: 2,766
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    They were all performed in indoor labs Homer . This I can guarantee
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC
    732-751-1560
    Serving most of New Jersey, Eastern Pa .
    Consultation, Design & Installation anywhere
    Rich McGrath 732-581-3833
    Gordy
  • lchmb
    lchmb Member Posts: 2,997
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    so I'm curious... Does the price of NG change with usage or does everyone in the area pay the same price? In the case of LP most pricing is based on usage... use more-pay less...
  • HomerJSmith
    HomerJSmith Member Posts: 2,468
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    Rich, of course that's how it's done with a lot of P.E.'s in a lab where all the variables can be controlled.

    I am aware that, when you're testing, you are looking at a specific objective, you control all variables except the one you're testing for. Combustion air is a variable.
  • flat_twin
    flat_twin Member Posts: 350
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    lchmb said:

    so I'm curious... Does the price of NG change with usage or does everyone in the area pay the same price? In the case of LP most pricing is based on usage... use more-pay less...

    Our NG is provided by a cooperative. Price per ccf can vary month to month depending on the market. All residential customers pay the same rate regardless of usage. Not sure about businesses. Because it's a cooperative we don't have the option to shop around for competitive rates.
    Prices have varied between 1.11 and 1.20 per ccf in the last two years.

  • NY_Rob
    NY_Rob Member Posts: 1,370
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    lchmb said:

    so I'm curious... Does the price of NG change with usage or does everyone in the area pay the same price? In the case of LP most pricing is based on usage... use more-pay less...

    In NY you can purchase your NG through a 3rd party provider, but you must still pay National Grid for "delivery and infrastructure" to get the gas to your house.
    The "delivery and infrastructure" charge from Ntl Grid is the same no matter if you purchase the gas from them or a 3rd party provider.
    The difference in the actual "gas used" price between Ntl Grid and the 3rd party sellers can be quite can be quite dramatic during peak seasons. I have a 3-yr fixed price contract with my gas seller at 61 cents/therm. Over the past several years in cold months I've seen National Grid go as high as $1.22/therm.

  • Brewbeer
    Brewbeer Member Posts: 616
    edited February 2018
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    NY_Rob said:

    What is amazing to me is the fact that 8K BTU's can heat your house, even at freezing outdoor temps. 8K BTU's is the output of one of our stove top burners we use to make a pot of tea!

    Non-heating system inputs are important considerations when temps are mild and houses are well insulated. Just about all electrical usage inside the house turns into heat energy, and people put out about 300-400 BTUs/hr. If a family of 4 is home and they are using 2 kW/hr in electricity, that's a net heat input of at least 5,000 BTUs per hour into the house.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
    NY_RobGordyCanucker
  • Gordy
    Gordy Member Posts: 9,546
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    Not counting solar gain.
    BrewbeerCanucker