Ceiling fans cost pennies per hour to run and can significantly reduce AC costs when used correctly. Here is how to get the most from them.
How Fans Help
Fans do not cool air - they cool people. Moving air accelerates evaporation from skin, making you feel 4-6 degrees cooler. This allows higher thermostat settings while maintaining comfort.
Summer Settings
Direction: Counterclockwise (looking up at the fan). This pushes air down, creating the cooling breeze.
Speed: Higher speeds create more airflow and greater cooling effect.
Thermostat adjustment: For every degree you raise your thermostat, you save about 3% on cooling costs. Fans allow 4+ degree increases.
Turn off when leaving. Fans cool people, not rooms. Running fans in empty rooms wastes energy.
Winter Settings
Direction: Clockwise (looking up at the fan). This pulls air up and pushes warm air at the ceiling down along the walls without creating a draft.
Speed: Low speed prevents wind chill while circulating warm air.
Benefit: Destratifies air, bringing warm air from the ceiling down to living level. Most helpful with high ceilings.
Fan Selection
Size: Match fan size to room size. Larger rooms need larger fans or multiple fans.
Quality: Better fans move more air more quietly. Look for CFM (cubic feet per minute) ratings.
Location: Center of room or over seating areas for maximum benefit.
Combining with AC
The optimal strategy: 1. Run fans in occupied rooms 2. Raise thermostat 4-6 degrees 3. Turn off fans when leaving
This typically saves 10-15% on cooling costs while maintaining comfort.
Common Mistakes
Running fans in empty rooms. This wastes electricity without benefit.
Wrong direction. Clockwise in summer creates updraft, not cooling breeze.
Forgetting fans when adjusting thermostat. If you raise the thermostat, make sure fans are running.
Overly relying on fans in extreme heat. When temperatures exceed body temperature, moving air does not help much. AC becomes necessary.
Bay Area Applications
Fog belt: Ceiling fans may provide all the cooling needed most days. Use AC only during heat waves.
Inland: Combine fans with AC strategy. Pre-cool home in morning, then use fans to stretch the cooling during peak afternoon.
Evenings: Bay Area temperatures usually drop at night. Fans plus open windows can eliminate AC need in evenings.
Cost Comparison
Ceiling fan: ~$0.01-0.02 per hour AC: ~$0.10-0.25 per hour
Every hour you can use fans instead of AC, or reduce AC runtime with fans, saves money.
Ceiling fans are one of the simplest, most cost-effective ways to improve comfort and reduce energy costs.