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  1. #1

    Furnace replacement - variable speed versus single stage

    We are currently in process of replacing furnace and ac and are looking for an independent view on pros and cons of variable speed and single stage units. We are in the Midwest and have a 2 story colonial that is not dual zoned. The second story seems to stay cool with our existing single stage 90% American standard which needs replacing. What are pros and cons of single and variable units? Would a variable speed blower help or hurt the situation on the second story? I acknowledge that This could easily be an insullation issue too hat will not be solved with a furnace.

    We have gotten bids for York goodman, Westinghouse and bryantt. Any views on equipment would be appreciated too.

    Thanks.

  2. #2
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Don't focus on the brand, focus on a good contractor.

    One who will design your system properly, address any existing issues and be there on that cold night/hot day when you need them.

  3. #3
    Join Date
    Oct 2010
    Posts
    10
    Varible speed is best used with 2 stage cooling. Some single stage cooling systems will require the VS furnace to qualify for the Fed tax credit. VS is slow ramp up and slow ramp down, a more efficient motor, and many fan speed settings. In a reg. furnace, blowers have 3-4 speeds......but 90% time its high cool, low heat..

  4. #4
    Join Date
    Oct 2010
    Location
    SW Michigan, near Battle Creek
    Posts
    921
    the biggest thing I have against multiple input furnaces is repair parts
    sticker shock and availibility.
    the variable blower motor is nice. replacement is pricy but reliability seems real good.
    and a standard motor can be scabbed in to get heat for the night of a failure.
    and the variable will move the right amount of air for less electicity

    I like a heat pump with a single input furnace with a variable fan drive
    a two stage heat pump is nice
    a two stage furnace is nice (but see above)
    a modulating furnace is premo (but see above)

    oversize is not better!!!!!

  5. #5
    Join Date
    Oct 2010
    Location
    Overland Park, KS
    Posts
    166
    I always presented variable speed in a couple of ways from the sales side of things. With the federal tax credit, in some cases you have to go variable speed if you are trying to achieve the tax credit on the AC side.

    However, it's up to you on which direction to go to achieve the tax credit, because a standard 95% furnace qualifies also. Depending on where you live in the midwest, it may be more beneficial to go for the tax credit on the furnace portion than the AC side. Because in reality, the difference in savings on the AC side from a 13 seer to a 14 seer to a 16 seer isn't a huge jump. You CAN though, gain comfort when you get into the 2-stage AC's. And on those you need the variable speed.

    I always gave my customers several options, and treated my presentation as a true ROI. It only makes sense to be energy efficient if, over the life of the equipment, you get some return on that money in terms of energy savings.

    So depending on the numbers, variable speed may make sense. Do you HAVE to have it? No, unless you go with a 2-stage AC. Is it nice to have? Yes, because you can get a more even air-flow in the house which will translate into more comfort.

  6. #6
    Join Date
    Oct 2010
    Location
    SW Michigan, near Battle Creek
    Posts
    921
    high efficiency heat pump!!
    save on cooling save on heating. some redundancy in heating.

  7. #7
    Join Date
    Jun 2009
    Location
    Albuquerque NM
    Posts
    2,484
    Quote Originally Posted by Gerfen View Post
    We are currently in process of replacing furnace and ac and are looking for an independent view on pros and cons of variable speed and single stage units. We are in the Midwest and have a 2 story colonial that is not dual zoned. The second story seems to stay cool with our existing single stage 90% American standard which needs replacing. What are pros and cons of single and variable units? Would a variable speed blower help or hurt the situation on the second story? I acknowledge that This could easily be an insullation issue too hat will not be solved with a furnace.

    We have gotten bids for York goodman, Westinghouse and bryantt. Any views on equipment would be appreciated too.

    Thanks.
    Your contractor needs to address your uneven temperatures.

    If your current equipment is oversized, it is contributing to your uneven temperatures. Make sure your hardware is properly sized.

    2-stage heating and cooling will usually provide better comfort.

    If had a two story house, I would have it zoned or have two systems.

  8. #8
    Join Date
    Feb 2010
    Location
    The midwest.
    Posts
    663
    Quote Originally Posted by Gerfen View Post
    We are currently in process of replacing furnace and ac and are looking for an independent view on pros and cons of variable speed and single stage units. We are in the Midwest and have a 2 story colonial that is not dual zoned. The second story seems to stay cool with our existing single stage 90% American standard which needs replacing. What are pros and cons of single and variable units? Would a variable speed blower help or hurt the situation on the second story? I acknowledge that This could easily be an insullation issue too hat will not be solved with a furnace.

    We have gotten bids for York goodman, Westinghouse and bryantt. Any views on equipment would be appreciated too.

    Thanks.
    IMHO the "variable-speed" blower is the ONLY way to go.

    It's 25%-75% more efficient, quieter, increases the A/C SEER, better dehumidification and better comfort.

    Plus, it's a must if you are thinking of adding zoning later.

    It's more than worth the (little extra) money.

  9. #9
    Join Date
    Oct 2010
    Location
    SW Michigan, near Battle Creek
    Posts
    921
    variable motor-controllers are pricy to replace
    probably will not have to but....

    makes a long parts warranty worh thinking about

  10. #10
    Go with a reputable contractor and i would use the Bryant or York my opinion stay away from Goodman it is builders model to me i dont care what anybody else says. i have been on to many calls for goodman install was good but equipment poorly built thats just my opinion.

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