Whole house fans are rated by CFM (cubic feet per minute of air moved), and choosing the right size depends on your home's total square footage and ceiling height. An undersized fan won't cool effectively, while an oversized fan can create excessive noise or require more attic ventilation than is practical to add.

  • CFM sizing based on home square footage and ceiling height
  • Balances cooling effectiveness against fan noise level
  • Confirms attic ventilation can support the recommended size