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  1. #1
    Join Date
    Mar 2008
    Posts
    4

    Question Blower motor AMP draw

    Hi All,

    This winter I decided to leave my blower on all the time. It really helped regulate the temp in the house. I was shocked when I got my electric bill today. I went out and bought an amp clamp from Menards and started taking readings. I pulled the furnace fan switch electrical cover off and took a reading on the switch wire there with the clamp. 9.1 Amps just running the motor?? I have a 2500SQFT home. The sticker on the inside of the HEIL unit says 12amps MAX Model: NTG3125KJA5 125,000 BTU

    Does 9.1 amps sound right just running the blower? I did the math and that costs me aronud 66 bucks per month! My friends have told me they run their fan and didn't notice much of a spike.

    I am also wondering if I can buy a different motor that doesnt use so much juice. The measurement was taken with this tool:

    http://www.hardwareandtools.com/invt/2873412


    Any help would be appreciated!

  2. #2
    Join Date
    Sep 2002
    Location
    I don't know
    Posts
    2,903
    1. Stop running the blower continuously, or...

    2. Have the blower motor wirewired so that continuous fan operates on low speed. Depending on the furnace, electrical components (can't get specific here) may need to be added. This will reduce energy consumption, but don't expect more than a 50% reduction.

    3. Replace the furnace with one that is equipped with an electronically commutated blower motor. (ECM/Variable speed) ECMs are much more efficient than conventional blower motors on low speed. (They often draw <100W on low) If the existing furnace is not anywhere near the end of its lifespan, this option is not preferable for obvious reasons.

  3. #3
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,051
    You did this with the blower door off, didn't you.

    If so, its not a correct reading.
    And I'm not allowed to tell you how to do it right.

    Also, many times, when you turn the stat fan switch to on.
    The blower runs at high speed, when it may normally run at med.
    Your not going to find anothe motor that uses less electric and still move enough air in both heat and cool mode, to the point that it would save you enough to pay for itself in the next 5 years.

    Your friends may have units with VS blowers, they don't use as much electric when in fan on mode. Because they run at half speed.
    Your friends may also have smaller furnaces.
    They may not pay much attention to their electric bills.

    In my area, a standard blower such as your, is usually about a 50 dollar jump in the electric bill. So your isn't out of line.

    Some of the higher end stats, have fan recirc ability. That may save you more. If the system hasn't run in an hour, it brings the fan on for 20 minutes. Should only cost you a third in electric of what the fan running 24/7 is.
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  4. #4
    Join Date
    Jul 2001
    Location
    Gold Coast of Connecticut
    Posts
    4,582
    Quote Originally Posted by beenthere View Post
    You did this with the blower door off, didn't you.

    If so, its not a correct reading.
    And I'm not allowed to tell you how to do it right.

    Also, many times, when you turn the stat fan switch to on.
    The blower runs at high speed, when it may normally run at med.
    Your not going to find anothe motor that uses less electric and still move enough air in both heat and cool mode, to the point that it would save you enough to pay for itself in the next 5 years.

    Your friends may have units with VS blowers, they don't use as much electric when in fan on mode. Because they run at half speed.
    Your friends may also have smaller furnaces.
    They may not pay much attention to their electric bills.

    In my area, a standard blower such as your, is usually about a 50 dollar jump in the electric bill. So your isn't out of line.

    Some of the higher end stats, have fan recirc ability. That may save you more. If the system hasn't run in an hour, it brings the fan on for 20 minutes. Should only cost you a third in electric of what the fan running 24/7 is.

    Change the stat, ot maybe look at a new furnace. Think of what you would save with a ECM blower over 10-20 years.
    Aire Serv of SW Connecticut- Gas heat, dual fuel and central a/c systems installed and serviced

  5. #5
    Join Date
    Mar 2008
    Posts
    4

    Thanks

    Thank you for the responses. Sounds like this kind of extra engergy use is not uncommon and the best solution for me would be not to run it all the time.

  6. #6
    Join Date
    Apr 2007
    Location
    Dallas TX
    Posts
    192
    Do you have annual maintance on your system? There are some companies begining to offer ECM motors as replacement for the more power hungry PSC blower motors. When your maintenance tech says your blower motor will need to be replace soon, then it can be more cost effective to replace just the motor and there will not be a rush to get the house back to normal comfort.
    Just make sure your local company is willing to support it!!!

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