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  1. #40
    Join Date
    Mar 2002
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    Concord, CA
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    2,635
    Originally posted by davidr
    Don't you think that makes the rating game just a little deceptive?
    For the purposes of comparing one machine to another, no.

  2. #41
    Join Date
    Sep 2002
    Posts
    186
    Here is my 15 cents worth of nothing. In my house I removed an 1987 carrier 80% and replaced it with a carrier 90%. It on LP last year we have saved about $45 I expected more. The duct work is the same,no changes made to the house.
    Because chicks dig it.

  3. #42
    Join Date
    Aug 2003
    Location
    Central Kentucky
    Posts
    6,247
    Originally posted by Irascible
    Originally posted by davidr
    Don't you think that makes the rating game just a little deceptive?
    For the purposes of comparing one machine to another, no.
    This is rarely how it's made known to the public though.

    The majority of homeowners are being told a 90% furnace & high SEER A/C will automatically produce this same level of efficiency once installed in their homes.

    That is what I consider deceptive,so I should have rephrased the comment.
    Have you set up a Google alert for Carbon Monoxide yet?
    Click here to find out how.

  4. #43
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    Originally posted by davidr
    The majority of homeowners are being told a 90% furnace & high SEER A/C will automatically produce this same level of efficiency once installed in their homes.

    That is what I consider deceptive,so I should have rephrased the comment.
    Are they actually told that? Or is it that salesmen simply avoid the subject of nominal vs. delivered ratings and let the customer believe whatever they believe? It seems to me that most salesmen avoid anything too terribly technical. In either case, I understand what your saying. Most customers are indeed ignorant on the topic and most likely do believe that an 80+ furnace delivers 80% of its heat to the house.

  5. #44
    Join Date
    Mar 2004
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    Here is some information from “the CO God” to feed your minds:

    Jim Davis:
    Burner efficiency or real efficiency? When it comes to the amount of fuel that a burner burns, most burners are 99.99 percent efficient assuming a maximum of 100ppm of CO. The incorrect information is what percent of the actual BTU value of the fuel is created. At perfect or stoichiometric combustion this would be 1000 BTU(approx)per cubic foot of gas. In the real world fuel is converted to about 90% of the BTU's it is rated. This is because the air we use contains nitrogen(79%) which robs the flame of heat value. A perfect gas flame would burn at 3600 degrees but the normal temperature we create at 6% O2 is 2800 degrees. If your O2 is 10% then your flame temperature is even cooler-2200 degrees and now you are only creating about 80% of the available BTU's. Combustion efficiencies and AFUE assume a 3600 degree flame. Out of the BTU's actually created we must now transfer this to the air, water or steam. The only way to evaluate true efficiency is to measure the actual BTU's delivered to the air, water or steam (Thermal Efficiency). Maximum Thermal efficiencies on old furnaces is about 69%, 80% furnaces is 72% and 90% furnaces is 88%. Overall efficiencies of 2-stage is much lower. One additional note is that AFUE rating do not include electric usage and variable speed furnaces use $200-$300 less than conventional and are the better value, minus the 2-stage operation which probably offsets this savings, but that can be corrected.


  6. #45
    Originally posted by madeinusa
    Maximum Thermal efficiencies on old furnaces is about 69%, 80% furnaces is 72% and 90% furnaces is 88%.
    Which makes the actual difference 88-72 = 16% instead of the 10% calculations that I provided you.

    Do you really want the new improved numbers to make your "Efficiency" argument look even worse?

    School is coming up, I gotta go to get my lesson prepared for tonight’s class.

    Be studying so you can keep up....

  7. #46
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    You missed the sentence at the bottom where he said, “Overall efficiencies of 2-stage is much lower.”

  8. #47
    Originally posted by madeinusa
    You missed the sentence at the bottom where he said, “Overall efficiencies of 2-stage is much lower.”
    Hey DIP****, don't change the material.

    The discussion is on the Efficiency differences between 80 & 90 percent units. Nothing has been said about "two-stage" units up till now.

    You are trying to change the subject cause you know you are ALREADY Losing!

    But while we are on this subject change, a two stage could operate at 82%. While, the other units are operating at 88 & 72 percent.

    So take the regular 80% unit (at 72%) and the 90% two-stage unit at (82%). That 82 is "much lower" than the normal single stage 90% unit (at 88%), but stills saves you TREMENDOUS (10 percent) amounts of money over the normal 80% (at 72%)!

    BTW, people buy two-stage units for COMFORT!

    What else do you want to throw out WonderBoy?

  9. #48
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    Originally posted by jultzya
    You are trying to change the subject cause you know you are ALREADY Losing!
    Actually, I have already won because you have had to reconfigure your math to reality.

    This wonderboy doesn't want to overwork you in one day.

  10. #49
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    Mar 2004
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    Originally posted by davidr
    I believe the issue made is making with 90% vs 80% has to do with 2 stage 90% equipment in low fire,am I correct in my assumption made?
    I didn't want to send them to the mental ward all in one day just yet.

  11. #50
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579


    The quality of the installation is paramont as to which will last longer.

  12. #51
    Originally posted by madeinusa
    Originally posted by jultzya
    You are trying to change the subject cause you know you are ALREADY Losing!
    Actually, I have already won because you have had to reconfigure your math to reality.
    I guess you forgot what you said last night?

    You said,

    You do not get actual 95% or 80% output at the ducts into the home or business, and that is actual true BTU's into the envelope.
    The heat gain with-in the envelope is increased proportional to the efficiency of the equipment installed, PERIOD!

    Whether it is 80 vs. 90 or 70 vs. 80 you are gaining EFFICIENCY!

    You contradicted yourself last night. What's the problem, where you intoxicated last night and don't remember the conversation at hand?

    Would seem to be this way... since you have already taking a high road and started changing the original topic of discussion.

  13. #52
    Join Date
    Apr 2004
    Posts
    7,680
    Well that and how well it's maintained and treated. A great installation can not help much if the filter is never changed, dampers are shut, and maintanence is never performed.

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