Building Green Homes
Fans
Allowing natural air to flow in and out of the home on days with a comfortable air temperature or cool nights following a warm day is one of the most efficient ways to reduce energy costs. Natural air ventilation can provide a comfortable and fresh air within the home. Fans can help circulate air through the home and ventilate a space.
When considering to use fans to cools a home, a homeowner must take into account several other factors besides outdoor air temperatures. Humidity, pollen levels, and dust should be taken into account before deciding whether to use a fan for cooling.
Ceiling fans do not cool or dehumidify the air, but rather they deliver a wind chill effect against the skin, cooling the body. Using a ceiling fan as opposed to air conditioning is a great way to reduce energy use, but make sure to turn the fan off when you leave the room to conserve energy.
Window fans are another alternative that can be used if homes do not have ceiling fans. Window fans can be set to blow cooler air from the outside into a room or be set to draw warmer air from the inside to the outside of the home.
A whole house fan is another way to go, but usually these fans are installed by a professional in the attic. Whole house fans are used when outdoor temperatures are cooler than indoor temperatures, and they help circulate the cooler air indoors. Whole house fans can save homeowners 50 - 90% on A/C bills, and have a return on investment within 1 year. They also help to ventilate indoor air pollutants and odors.
The size of a room determines which size fan would be most appropriate. The following is an ENERGY STAR chart that reccommends what blade size is appropriate for specific square footage of rooms.
A fan size of 52" is the most common
This graphs compares the daily cost of a ceiling fan vs. air conditioning.
Spotlighting, "Ceiling Fans Vs. Air Conditioning: A Story of Energy-efficiency, Cost Savings and Style", 17 Sept. 2013
Quiet Cool is a company that sells whole house fans. This is a video created by Quiet Cool that describes how whole house fans work and how they can save homeowners a lot of money!