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  1. #1
    Greetings,

    I've been running my furnace blower continuously since it was installed in 1992, because I like to run the Honeywell electrostatic air cleaner all the time (dust/mold allergies have pretty much disappeared since I started doing this). It also reduces some of the temperature differential between upper and lower floors of the house (single zone).

    Now that these fancy variable-speed air-handlers are available, with the new efficient ECM motors, I'm feeling efficiency-envy, yet replacing the furnace is not in the cards just yet. I'd like to replace the blower in my furnace in order to reduce electricity usage. I've read a study or two that indicates a 2-year payback, possibly less if you run the fan all the time like I do. Here are a couple references:

    http://repositories.cdlib.org/lbnl/LBNL-54760/
    http://www.aceee.org/pubs/a033full.pdf

    In particular, I'd like for the blower to run at a reduced speed when not heating; This would reduce noise level a bit, perhaps improve the wind-chill factor, but especially it will save electricity (some are saying 70-90% less, if you go with lower fan speeds). Guess I'm wondering if the furnace blower controls will support this mode of operation.

    Any advice on this little project? If you were a contractor in my area (Portland, OR), would you be willing to do it?

    The first paper listed above indicates the importance of matching the motor to the blower wheel and its housing. Where would one go to find such a thing?

    Thanks for any info/advice you can provide.


  2. #2
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Definitely need to call a contractor to do this for ya. Just remember, it will be fairly costly(might want to go ahead and replace the whole unit anyways). I know some very reputable companies in Portland who can take care of this for ya. Email me at joshy_22_2000@yahoo.com for more info.

  3. #3
    Join Date
    Sep 2002
    Location
    I don't know
    Posts
    2,903
    An upgrade may void the warranty and present issues with an insurance claim if something related to the furnace were to happen. Each unit is given a UL/CSA/whatever certification based on the original OEM design.

    You might want to call a tech and ask about running the blower at a lower speed when there is no call for heat. There are fan manager/control boards designed to do that; in fact many recent (standard motor) furnaces run in low for continuous air circulation and kick into medium/high speed when heating or cooling is taking place.

    I'm no technician, but posting the model number might be of benefit for others when they respond.

  4. #4
    Join Date
    Sep 2001
    Location
    Vancouver Canada
    Posts
    996
    Bad news for you, replace your unit if you are looking for variable speed. It is really not feasable to put a DC variable speed motor into a furnace that is 13 plus years old. You would need not only the motor but also the control board to operate it.
    "Go big or Go Home"

  5. #5
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Take a look at this. It isn't an ECM blower, but I find it interesting.

    http://www.fanhandler.com/
    If more government is the answer, then it's a really stupid question.

  6. #6
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    what is the voltage used by the present blower?

    what is the amperage drawn by the present blower, just before you clean the filter? [your motor may not be needing full amperage, or may need more than --]

    what is your kwh rate?

    kwh~volts * amps *hours.

    so, 1/3hp motor= 1/3*745w ~250w/h; at $0.1/kwh = $0.1 ea 4hr or $0.6/d or $18/mo [at full load, rated speed, etc]
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  7. #7
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,739
    Originally posted by amd
    An upgrade may void the warranty and present issues with an insurance claim if something related to the furnace were to happen. Each unit is given a UL/CSA/whatever certification based on the original OEM design.

    You might want to call a tech and ask about running the blower at a lower speed when there is no call for heat. There are fan manager/control boards designed to do that; in fact many recent (standard motor) furnaces run in low for continuous air circulation and kick into medium/high speed when heating or cooling is taking place.

    I'm no technician, but posting the model number might be of benefit for others when they respond.

    this is the right thing to do if you are not ready for new heater. unit was approved with setup you have. major changes would void approvals.

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