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How Efficient is Your Fan Motor?


Understanding Different Types of Fan Motors

I last talked about high efficiency furnaces that are 95-98% efficient. Another feature that has occurred in the last 5-10 years is efficiency of fan motors.

Standard Fan Motors
Standard fan motors have three set speeds. Low, for air circulation, middle, to move heated air and high, to move cold air (from your air conditioner) thru your duct work. If these fans are being run for 24 hours continuously, they will use approximately 750 watts of energy.

High Efficiency Fan Motors
High efficiency fan motors are quieter and do not have set speeds. These fan motors ramp up and down depending on what speed is needed. They also do a better job of balancing the temperature and controlling airflow throughout the house. These fan motors will use about 200 watts of energy in a 24 hour period.

Variable Speed Fan Motors
Now there are variable speed fan motors, which were introduced approximately 5-7 years ago. This type also ramps from low to high, and are even quieter than high efficiency fan motors. Variable speed fan motors, when coupled with a 95% or higher furnace, qualifies for a $350 State of Oregon Tax Credit. The amazing part of this fan motor is the low electrical usage. Running it for a 24 hour period will use about 75 watts of energy. So you could run this fan constantly for 24 hours over a 10 day period for the same cost of running a standard fan motor for one 24 hour period. Plus it will do a far better job of conditioned air distribution.

Stay tuned for my next blog post on the benefits of multi-stage furnaces.

[ Photo by: carlpenergy, via CC License ]