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Aug 09: Be a Fan of Fans

Currents Summer 2009 Newsletter

Compared to parts of the country that have much greater summer cooling needs, we have more options to keep ourselves comfortable affordably and sustainably. Unless you have someone in your home who needs central air conditioning for health reasons, we challenge you to look to room air
conditioners and fans, particularly ceiling fans. Here are some tips, offered by the American Council for an Energy Efficiency Economy.

  • Window fans. Fans uses less energy than air conditioningand can meet desired comfort levels in our climate. Window fan units can be very effective.
  • Ceiling fans. Ceiling fans cool by creating a low-level “wind chill” effect throughout a room. As long as indoor humidity isn’t stifling, they can be quite effective. Just remember that a fan cools people — it doesn’t actually reduce room temperature — so turn it off when you leave the room. Look for ENERGY STAR rated ceiling fans. If you buy a fan with lighting included, ENERGY STAR rated units are about 50% more efficient than conventional units.
  • House fans. Installing a large fan in your top-floor ceiling is a very effective way of cooling your entire house without central AC. These fans draw air through the house, inducing a strong draft in rooms where windows are open as it pulls cooler, outdoor air inside. In some cases, you can run them for a short time in the early morning, when the air is coolest and humidity is lowest, close the windows, and your home will stay cool for quite a while. Check with your local home improvement retailer about available products and installation.
  • Room air conditioners. These types of units are rated by EER, which is cooling output divided by power consumption. The higher the EER, the more efficient the air conditioner. When choosing a room air conditioner, resist the temptation to buy the cheapest unit—it may be the most expensive in the long run when you add in the cost to run it. ENERGY STAR requirements exceed the federal standards by 10% or more. Room air conditioners are sized to cool just one room, so several may be required for a whole house. Individual units will cost less to buy than central systems. ACEEE recommends an EER of at least 10.8. Buy ACs that have earned the ENERGY STAR logo and buy the highest EER you can.
  • It is critical that your window unit is properly sized. Too much capacity and the unit will cycle on and off too often, wasting energy. Too little and the unit will not cool well and will overdry the air. Note that square footage is not the only factor governing cooling capacity. As an example, if your room has a lot of windows exposed to summer sun, ceilings higher than 8 feet, or might be higher than average. If you are going to install central air conditioning, we strongly encourage you to purchase the most efficient system you can afford. Look for EnergyStar units.


One final point: At the wholesale level, electricity prices are highest during peak periods – a few very hot days in the summer or really cold days in the winter. To meet peak demand, the electric grid needs more fossil fuels in the mix. Even though these periods occur just a few days per year, they drive up the average price we pay for electricity all year round. Anything that we can do to reduce peak energy use saves money for everybody and reduces our collective environmental impact.
That is another reason we are fans of fans.