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  1. #27
    Join Date
    Aug 2002
    Location
    Westlake, Ohio
    Posts
    2,538
    Originally posted by fat bob
    Originally posted by Jim Davis
    Running the blower too fast would also make the furnace less efficient because the air doesn't make enough contact with the heat exchanger to absorb any heat.
    I don't see how this can be true. With any hot object sitting in front of a fan, increasing the fan speed will increase the transfer of heat from the object to the surrounding air. It's just basic thermodynamics that heat transfer increases with the temperature difference between the air and the object. When air moves more slowly across the object, the air heats up more and the heat transfer slows down. But maybe I'm missing something.

    [Edited by fat bob on 02-10-2006 at 04:10 PM] [/B]
    If that is true how come I can pass my hand right through the flame of a candle and not get burnt?
    TIME-TEMPERATURE-TURBULANCE

    Why does an A/C freeze up if you run the fan too fast?
    captain CO

  2. #28
    Join Date
    Aug 2002
    Location
    Westlake, Ohio
    Posts
    2,538
    Originally posted by nord 64

    "Low fire is always less efficient than High fire when it comes to BTUs delivered to the air stream versus gas input."

    If that is true, how come that the manufacturers state the opposite?

    For example, on my 2 stage Lennox the %age of input BTU's versus output BTU's (delivered to the air stream) is higher in low fire.

    Why would Lennox state wrong information in the manual and on the furnace with regards to input/output BTUs, and therefore efficiency?

    I'm not convinced that low fire is less efficient just because a "pro" is writing it.

    What am I missing?



    Don't want you to believe it, I want you to go out and measure it. I have for 28 years, initially with commercial and industrial and then residential but nothing changed. Low fire uses considerable more fuel than high fire. They are designed for comfort not efficiency.
    captain CO

  3. #29
    Join Date
    Dec 2005
    Location
    Canada
    Posts
    61
    Jim Davis,
    When that is true, how come the numbers given by the manufacturers (in my case Lennox) are different?

    How can Lennox post false numbers?
    Afterall, if you know that the numbers are not right they will know too.
    What is their motive of given false data?


  4. #30
    Join Date
    Nov 2004
    Posts
    2,927
    Originally posted by whitedog
    An installation done to the manufacturer's spec would increase my confidence that the furnace is most likely functioning at its best.


    It's more than just a nice thing to do ... it's the Law.

  5. #31
    Join Date
    Aug 2002
    Location
    Westlake, Ohio
    Posts
    2,538
    Originally posted by nord 64
    Jim Davis,
    When that is true, how come the numbers given by the manufacturers (in my case Lennox) are different?

    How can Lennox post false numbers?
    Afterall, if you know that the numbers are not right they will know too.
    What is their motive of given false data?

    Manufacturers do not set the efficiency standards. They follow a set of guidelines that are based on theory not actual measurement. I have never tested a furnace that has out performed the Lennox pulse and yet I see lots of furnaces with higher efficiency ratings. How many posts are there a week on this site where homeowners have purchased new high efficiency equipment and their bills have gone up? If efficiencies were correct people should be saving money. Sure fuel has gone up but until now this has been a mild winter and is a wash, so people should still be seeing 20-30% savings.
    captain CO

  6. #32
    Join Date
    Dec 2005
    Posts
    42
    Hey Nord64.....wow this is all pretty confusing. Have you gotten any further information about the 1st stage, 2nd stage efficiency? I know our gas prices have gone up quite a bit, but our gas bill was 2.5 times as much as last year. We did use fewer therms for the month, but so far I have not gotten the feeling that I am saving much with the new high efficiency lennox. I guess it will take a year or so of comparison to really tell what is going on. I am not sure why the dealer/installer, did not go in to more detail about the 1st , 2nd stage issues. They pretty much just said my old furnace was about 60% efficient and that i would see substantial savings with the new high efficiency furnace. Its all so confusing.


  7. #33
    Join Date
    Dec 2005
    Location
    Canada
    Posts
    61
    Hi arlene,

    I'm sure I get the efficiency although I do not have more than 2 bills so far. I used 57 therm up until the 10th of february.
    That compares to 149 Therms last year. It has been warmer, I'm not sure how much yet waiting for the utility to tell me. My guess is 20-30 percent.
    I'm still making improvements to my house's efficiency like caulking and I insulated my heating ducts. Also, like I said before I get away with a lower t-stat setting. I used to have my setting at 67-69F and now I have it at 64-66F and I feel just as comfortable. I need more data to realy tell but I do not buy that 1 stage is way less efficient, it just does not make sense. Given the US environment where everybody sues everybody.....how can Lennox state that 1st stage is more efficient than 2nd stage? I trust that way more than anything. Even if it would be true, I use set backs and therefore my furnace runs a litte more on 2nd stage anyway, I'm in the middle of two extremes.
    Furnace is runnig smooth,quite and more efficient than my 73% AUFE AKA 1981 Lennox-by far.




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