A whole-house fan pulls cool outdoor air in through open windows and pushes hot, stale air out through the attic. It can reduce or eliminate the need for air conditioning during mild summer evenings. Installation costs $1,000 to $3,000 depending on the fan size and installation complexity.
Whole-house fans work best in dry climates where nighttime temperatures drop significantly. In San Antonio and the Texas Hill Country, they are effective from spring through early summer and again in fall.
How a Whole-House Fan Works
A whole-house fan is mounted in the ceiling of a central hallway, usually in a vertical chase or between attic trusses. When turned on, it pulls air from the entire house through open windows and exhausts it into the attic. The fan creates a strong breeze effect throughout the home, making it feel 5 to 10 degrees cooler without running the AC.
Energy Savings and Cost
Running a whole-house fan uses 50 to 150 watts, compared to 3,000 to 5,000 watts for a central AC unit. On mild evenings, using the fan instead of AC can reduce your electric bill by 30 to 50 percent for those hours. Installation costs range from $1,000 for a basic 36 inch fan to $3,000 for a larger fan with custom ducting and automatic shutters.
Texas Suitability and Climate
Whole-house fans are most effective in dry climates where nighttime temperatures drop below 70 degrees. San Antonio's humid July and August nights can limit their usefulness because the cool air carries high humidity. However, they work well from April through June and again from September through October. Homes in the Texas Hill Country with lower humidity benefit more.
