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25% less fuel usage?!?!

elamcup Member Posts: 8
We have a Weil-McLain Ultra 155 boiler and hot water baseboard heat in our home. I read some posts on this forum where I could save fuel by lowering my water temperature, so last month I lowered my water temp from 180 to 150 degrees. Today I got the gas bill and I was shocked. The daily temp was 5 degrees higher this year but my daily usage dropped by 25%!! WOW!!


  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    Lower temp = more condensation = less fuel

    Hate to say, but it sounds like the installer left 100% guaranteed no callback settings in your boiler. Good for him, but bad for your fuel bill!
  • Weezbo
    Weezbo Member Posts: 6,232
    wow *~/:)

    i wonder what 89 F water might net you ...i was under the impression it was a condensing boiler....
  • Bob Sweet
    Bob Sweet Member Posts: 540

    to the believers soceity.
  • Tony_23
    Tony_23 Member Posts: 1,033

    You need to connect and program the ODR function. If you're afraid it may not keep up under certain conditions, set the boost at 30 minutes. If you have a tight house set the boost at 0 minutes.

    We've seen 40% reductions in usage on bbd with Ultra installs (not ALL, but most).

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  • Why use boost if you use ODR? If you can program the ODR and it doesn't keep up, fix the ODR settings.
  • Plumb Bob
    Plumb Bob Member Posts: 97

    Well, you say your daily temperature was 5F higher this year. That's the primary explanation for the savings. Suppose the average temperature went from 45F to 50F, there's your 25% savings (ddays went from 20 to 15).

    Lowering the water temperature saves money, but not anything like 25%. Not gonna happen. Comparing an old boiler to a new boiler, sure, but not with the same boiler and only water temperature is lowered. 10% max if it goes from zero condensation to full condensation.

    It's amazing that no one else here pointed that out. I guess some people have a financial interest in having customers become "believers".
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    Guess I was being overly optimistic and thinking that compensation had been made for the difference in outdoor temperature.

    Also simplistic in suggesting that condensation was the only source of efficiency increase.

    Granted outdoor temp difference alone can account for all, some, or little of the change depending on the temps involved. Doubtful however that such was the only factor as you implied. We're both guilty of simplicity in that regard.

    The one TRUE SIMPLICITY that I find however is that the lower the temp used with a modulating/condensing boiler to accomplish the goal, the greater the efficiency. Efficiencies pile on top of efficiencies...

  • Tony_23
    Tony_23 Member Posts: 1,033

    an older, looser house loses more heat when the wind blows harder. The boost makes up for the added infiltration, in that instance. Ideally, boost wouldn't be necessary. When was the last time you saw an old house that was ideal ?

    Besides, at 18* every 30 minutes, the system "usually" hits the right temp before it hits limit.

    About 90% of my work is retrofit in homes built before 1970. I've tracked about a 40% reduction in fuel on bbd w/ Ultras set up this way. With a heat loss done w/o the benefit of x-ray glasses, and a curve set to such, the boost is insurance.

    Don't forget, some people WANT to have their unit shut off once in a while :)

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