A variable speed furnace blower provides a higher level of performance than a standard blower in that it features a high efficiency Electronically Commutated Motor (ECM) by General Electric.
This feature is important because full air delivery is only needed a small portion of the time. During lower demand times this motor reduces its speed, providing up to 4 times better humidity control in the cooling mode (when installed as part of an air conditioning system), better air distribution throughout your home, and greatly reduced operating costs.
Another important feature of a variable speed furnace is the reduction of what is referred to as "cold blow," or the cold blast of air upon heating startup. "Cold blow" results from cold air that develops in the duct system while the heat is in an off-cycle. When the furnace heater fan cycles on, this cold air is moved very quickly into your home resulting in an uncomfortable draft.
Variable speed furnaces virtually eliminate cold blow with a "soft start," or a gradual increase in fan speed over the initial 3 to 4 minutes of the on-cycle. This cold air is combined with preheated air from the furnace blower and is delivered at a slower velocity until it reaches full operating temperature. The result? Improved heating comfort and a dramatic reduction of the uncomfortable drafts associated with standard furnaces.
Better air distribution will provide a marked improvement in those areas of your home where air delivery has been a problem, such as the rooms farthest from the furnace.
In fact, a variable speed blower is so efficient that the low constant fan setting costs about the same to operate as an ordinary 75-watt household light bulb.
You and your family will appreciate the whisper-quiet operation of a variable speed furnace. The motor is among the quietest ever made and in fact, when combined with the generously applied foil-faced insulation, these are among the quietest furnaces available at any price.
The lower constant fan speed setting allows for greater removal of impurities by your furnaces' air filter. Click here to learn more about air filtration options.