Wednesday, July 10, 2013

Whole House Fans 101

Whole-House Fans.
Whole-house fans are installed in a central hallway inside the house and pull fresh outdoor air through open windows. They are often used to augment air conditioning or instead of air conditioning in mild summertime climates.



Benefits of Whole-House Fans:


  • Efficient cost-effective cooling
  • Can cut summer air conditioning costs and create a more comfortable living environment
  • Exhange air much more rapidly than air conditioning units, allowing faster cooling of the interior
  • Draw cooler air indoors, especially when used at night and early morning hours
  • Extract heat from objects within a house, such as appliances, furniture and walls

Design Considerations


  • For maximum effectiveness, a whole-house fan must be sized correctly for the structure it is required to ventilate.
  • The formula to follow for determining capacity is: square feet of living area x 3 = CFM (cubic feet of air moved per minute) required.
  • Because whole-house fans exhaust hot air into an attic, a properly sized attic ventilation system is required to exhaust heated air from the attic to outdoors.
  • To determine the net free area of attic ventilation required, use the following formula: CFM rating of fan divided by 750 = square feet of net free exhaust area.
  • Failure to provide this venting will reduce the fan's airflow capacity. In addition, it will lead to noisy operation and ultimately failure of the fan motor.




                                                                                  Belt-Drive Whole-House Fans



Whole-house fans are installed in a central hallway inside the house and pull fresh outdoor air through open windows. They are often used to augment air conditioning or instead of air conditioning in mild summertime climates.

  • Fan motor is attached to blade with a pulley for quieter operation than direct-drive models
  • Made with a rubber-mounted, self-aligning, precision ball bearing drive assembly to reduce friction
  • Feature two-speed operation, with a convenient wall-mounted switch
  • An enamel steel housing with a powder-coated finish makes them extremely durable
  • Sizes: 30" and 36"
  • Shipped in an assembled wood frame to simplify installation




Direct-Drive Whole-House Fans


Whole-house fans are installed in a central hallway inside the house and pull fresh outdoor air through open windows. They are often used to augment air conditioning or instead of air conditioning in mild summertime climates.

  • Feature two-speed operation, with a convenient pull-chain switch
  • A heavy steel housing with a powder-coated finish makes them extremely durable
  • Can be mounted without cutting an attic joist
  • Sizes: 24" and 30"
  • Shipped in an assembled wood frame to simplify installation