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  1. #1
    I am considering replacing an old 80 percent efficient, single stage furnace with a high efficiency, two-stage unit. I am also considering moving up to a two-stage furnace with a VSD. My question is two fold: (1) Is the VSD unit worth the investment in terms of potential electricity saved? I do have central air that does not run all summer, since I live in Buffalo, NY. (2) What is the anticipated life-span of a VSD blower motor and what is a rough cost of replacement should a motor fail? Thank you.

  2. #2
    vs units will raise your air conditioners seer by 1 to 2 ratings, remove more moistue, use less amps operating and with the right system you can do many things.
    carrier has the best technology i have seen with these high seer systems. some people will argue and say someone else systems are as good or better but ive worked on a lot and its always the same carrier is the technology leader and every one else follows. trane has a really good vs system but they donot have the super-dehumidification mode. trane loweras the temp setpoint when hum. goes up carrier slows the fan and drops the coil temp which removes more moisture to get the humidity down. but both are great.

  3. #3
    Join Date
    Jul 2002
    Logan Twp, NJ

    as a educated (But not DIY) homeowner, you will see extremely happy with a VS 2 stage.

    guess why. The house will be more comfortable all year. It's only adding puffs of warm air in the winter to maintain the temps, and runs longer at low speed in the summer to really pull out the moisture.

    If you have the ability and money for a VS, I'd see about zoning too.

    I have a 2611sqft home, 2 zones with the Bryant (carrier) 2 stage VS (90+%) with a stage stage compressor.

    The house is never cold or hot and is ALWAYS comfortable.

    PLUS, my bills are very very low.

    I had a combustion blower fail, but since I bought the 10 year full warranty, it was FREE! and I change the filter when my Therm. tell me. (30 day timer)

    don't think about saving electricity only, you are going to reduce NG gas prices too.

    have you checked your attic for proper insulation, I believe r-49 is what I had installed with r-19 in the walls. Helps a bunch too!!

    [Edited by AlexHatcher on 02-09-2006 at 01:23 PM]

  4. #4
    I agree VSM technology is the way to go but keep in mind Lennox invented the variable speed furnace/AHU. You would be remiss not to check them out.



  5. #5
    Thanks guys. I am wondering if anyone has a ball park estimate for the percentage of electricty savings going to a VSD blower motor? Also, do the VSD blowers run 24/7?

  6. #6
    Join Date
    Nov 2001
    Savings are based on your rates, and your useage.

    Not everyones are the same.
    The blower can run 24/7 but doesn't have to.

    The savings will be there when comparing the conventional motor, But more important will be the comfort and moisture

    Spend alittle more upfront to save everyday on total comfort.

    If you have the extra money now, then do it. You'll be glad you did.

    If you try to fail, and succeed.
    Which have you done ?

  7. #7
    Join Date
    Jul 2004
    You can download a energy savings calculator here. Lets you put in your electric and gas rates, pick your region, VS fan or standard fan, 24/7 run time or only as needed.
    It will give you a estimate of your savings

  8. #8
    Join Date
    Jan 2005
    Just another homeowners opinion.

    December 2004 we replaced our 46 year old furnace with a high efficient 2 stage non- VS model. Due to gross incompetence of the (now bankrupt) original contractor we were forced to replace the furnace again. We decided to upgrade to the VS motor model this time and we are more than happy with it.The house is more comfortable, excessive humidity problems have all but disappeared, and operation is considerably quieter. We have the fan running all the time and on low speed you can't even hear it run unless you are very close to the furnace. Its only been in 2 weeks now so its too early to calculate any energy costs but the manufacturer claims the DC motor uses 1/5 or less electricity than a standard motor. They claim that it uses about the same electricity as a 100 watt light bulb when operating.

    My contractor says the motor is about 2 x the cost of a standard motor but also claims that they seem to be very reliable.

    In my opinion I would spend the extra money for the VS motor.

  9. #9
    Join Date
    Nov 2000
    Waco, Texas, USA
    If you ran the blower 24/7 in the summer when the outdoor unit cycled off the duct system and supply grilles will still be cold. If the moisture on the coil re-evaporates it can condense on these cold duct surfaces.

    Am I right or wrong? Can you prove it?
    "And remember my sentimental friend......that a heart is not judged by how much you love, but by how much you are loved by others" - Wizard of Oz.

  10. #10
    Variable speed is quieter, delivers airflow at several different settings within a preselected range and is more efficient than a normally used PSC motor.

  11. #11
    Join Date
    Nov 2001
    Originally posted by Steve Wiggins
    Am I right or wrong? Can you prove it?
    You could be right or wrong,
    All I know is that I never see moisture on my floor grills
    during the summer.

    My ducts don't have mositure Ever. They are above my drywalled ceiling in the basement, that I can see from the unfinished side (storage area).

    I would think even if it did as you say re-evaporate, with the amount of moisture left on the coil, and the over aboundance of air flowing.
    I would think the air would evaporate the moisture before it had time to collect on the ducts or the grilles.

    Due to the fact that the air would now be more room air temp and not cooled air.
    Which in turn warms the duct surface temp.
    If you try to fail, and succeed.
    Which have you done ?

  12. #12
    Thanks pros for the insight, and thanks to the homeowners who shared their experiences. I am leaning heavily to a Heil VSII (or Tempstar..same unit) seems to be a solid mid-range unit...however, there seems to be some disagreement whether the blower unit should run constantly or shut off after the heat-cool cyclke has ended. Any thoughts on that. We use our AC sparingly in the summer, since we get a nice breeze off Lake Erie. But would running the fan constantly in thw winter months make any difference in comfort? I thought the two-stage feature helped end the heat-cool cycle and make the home more consistently warmer. In that context, does the VSD blower simply work to save money or does it supplement the two stage heating feature?

  13. #13
    Join Date
    Dec 2002
    Rochester, MN
    You will have to be the judge of yourself in your own home if you want to run the fan all the time.

    This what I do on mine since the Vison Pro allows me to program the blower.


    Day time/and when we are home, fan "ON"

    Night in Circ

    System turned off.


    Summer. fan in Auto, and night on Circ.

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