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Getting the most bang for my buck

firsthome
firsthome Member Posts: 3
Hello,





I purchased a home two years ago with a 1950’s Kohler 22

boiler with a carlin burner and taco recirculation pump. The Kohler also has a

domestic hot water supply attached to it that is tank less. There is one zone

in the system. At the recent cleaning the technician measured 78% efficiency at

the chimney. I have no problems with the system currently so I am not going to

replace it yet to gain another 10-15% of efficiency. I have two questions

though.





1 We burn approximately 1 tank 275 gals of oil for dhw from

May to September. Given the current oil price.





Should I consider shutting off the boiler for those months

and replacing with a traditional or hybrid electric hot water heater?





We have a well, temp is too low for on demand, and gas is

not available here.





In your experience would this effect the boiler that is past

its prime?





2 The basement is finished with approx 10’ of baseboard heat

to heat the room 21Lx14Wx7h I know that it is undersized and at the end of the

heating run.





Should I add another zone to this old system?





Or leave it alone and deal with the cool basement that we

don’t use often in the winter? I will upgrade when we replace the boiler

eventually.





In your experience would this effect the boiler that is past

its prime?

Comments

  • John Mills_5
    John Mills_5 Member Posts: 950
    Efficiency

    Remember, there are 2 efficiency numbers thrown around out there. Combustion efficiency is what your tech is measuring. That means once warmed up fully, the combustion process is 78% efficient in keeping the heat in the boiler. Don't confuse that  number with annual efficiency which is what you see on new boilers. Annual efficiency or AFUE tells what % of the heat produced heats the house over the entire season. So going to a new 85% AFUE boiler over your existing may not seem like much of an improvement, in reality it is. Your oldie could be as low as 55% efficient wasting a lot of fuel warming up, cooling down and during the off cycle.



    What is your cost per gallon of oil? What is cost per kwh of juice? That will tell if abandoning the tankless makes sense.
  • firsthome
    firsthome Member Posts: 3
    reply thank you john

    John,

    Thank you for the reply is there any way to determine the current efficiency of my system?



    I have heard from several contractors that it is probably only 50%

    efficient. How do they determine that?



    One contractor that was giving me

    the hard sell said it might be 30%.



    I know those are just estimates but

    I would like to compare apples to apples the cost of a new system

    versus my current system.



    I would like this to determine a cost benefit analysis for a new system.



    Kohler "22" fc-6



    110,000 BTU 1.45 gal hr



    175 degree h2o



    400 sqft steam/hot water





    I know we should not discuss installation prices but here are my numbers for a 1700sf raised ranch with a walkout basement and 2 bedrooms 1 bath over a crawlspace.













     

    oil used

    avg price

     

    total cost

    total degree

    days





    Total

    2009-2010

    1081.6

    2.7775

     

    $3,007.67

    3930





    Total

    2010-2011

    948.7

    3.308143

     

    3086.732

    4064





     

     

     

     

     

     





    CLP

    $0.11723 per KWh

     

     

     

     



    My 2011 is not over yet so hdd will increase through the end of the month.



    Kohler "22" fc-6

    110,000 BTU 1.45 gal hr

    175 degree h2o

    400 sqft steam/hot water
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,540
    A proper setup

    will knock 300,maybe 400 gallons off that 1100 gals/year. Call it $3.50/gallon = $1050-1300/ year,even assuming no inflation or rise in heating oil costs,that's $10,500-13,000 over 10 years
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  • firsthome
    firsthome Member Posts: 3
    Thank you Rob

    A proper setup

    will knock 300,maybe 400 gallons off that 1100 gals/year. Call it

    $3.50/gallon = $1050-1300/ year,even assuming no inflation or rise in

    heating oil costs,that's $10,500-13,000 over 10 years



    By shutting off the boiler during the summer I will save approximately 300 gallons per year. Buying an electric water heater, install and power for the first summer will be $1000-1300. After the first year $300 each subsequent year for power only. Using your estimation I would save $6200-8700 over 10 years



    Am I missing something or is this the better way to go?
  • Techman
    Techman Member Posts: 2,144
    edited March 2011
    What?

    What is the 110,000 btu and 1.45 gph, for?
  • Robert O'Brien
    Robert O'Brien Member Posts: 3,540
    1Kwh= 3413 BTU

    Or at 11.2 cents/kwh, $4.59 for the same 140K BTU in a gallon of oil. You're underestimating the cost of the electricity. The oil unit has eff losses which are substantial but still only bring it down to the $3/gallon equivalent range
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  • BobC
    BobC Member Posts: 5,476
    GE Hybird

    A friend of mine installed a GE Hybird (heat pump) hot water heater last spring and was very happy with the drop in his electric bill (vacation home in NH, elec costs about 0.18 per KWH). He calculated that hot water heater would pay for itself in 5 years (it costs about 3-4X what a regular HWH costs) and it's warrantied for 10years so it really was a no brainier for him.



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Ironman
    Ironman Member Posts: 7,367
    You May Want To Re-Consider

    If your numbers of 1.45 gph and 110,000 btu are from the boiler tag, then your boiler was 54% efficient when it was brand new and clean. You're probably under 50% now. That means for every $1.00 you spend on fuel oil, 50 cents is being wasted up your chimney!



    A new boiler would save you 40% or more on fuel if properly installed and set up with outdoor reset.



    The Buderus GB125E is over 90% efficient before outdoor reset is factored in. Couple it with a hot water indirect tank and you'll have a very efficient system that should last 40+ years and cut your consumption way down.



    With a 1700sq. ft. home, you should be able to use a boiler that's well under 100k btu's. Your current one is 203kbtu, if firing @ 1.45 gph.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
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