Air conditioning units, even the newest, most efficient models, occupy the top spot of the American energy consumption pyramid. On a normal summer day, no other household appliance consumes as much energy as the much-loved air conditioner — or even comes close. Roughly 25% of an average monthly electrical bill is consumed by a running air conditioning unit.
Now, consider the humble ceiling fan. A mid-size ceiling fan set on high for 12 hours per day costs just over a penny per hour in electricity or just about $3.50 per month. Even your curling iron uses more energy.
Three numbers to consider when shopping for a ceiling fan
Now that you are considering a ceiling fan to save money, you may as well consider an energy efficient one to further lower your household consumption. There are three numbers on the side of the box to look at:
- Airflow or CFM (Cubic Feet per Minute): Air flow, whether you’re talking about duct systems, bath fans, or ceiling fans, is measured in cubic feet per minute, usually called simply cfm. The higher the number, the more air is moving.
- Electricity Use (watts): Energy usage can be a bit confusing, but it’s important to remember that a watt is the unit of measurement for the rate of energy consumption. If the ceiling fan you are looking at includes a light, that will not be included in the electricity use rating to better allow an accurate comparison of the fan mechanism.
- Airflow Efficiency (or CFM/Watt): Efficiency is generally measured as output divided by input. In this case the output is airflow or CFM, divided by electricity use or watts
So what can we gather from these three numbers? You want high airflow or CFM with low electricity use or watts. Therefore, the higher the airflow efficiency number, the more efficient the fan. Other factors to consider are the size and height of the room. Energy Star provides an installation guide to help you choose the best size and mount for your ceiling fan. General rule of thumb is, get the biggest fan you can.
You have successfully installed your new ceiling fan. Now what?
As with any appliance, you have to know how and when to use it to get the best bang for your buck. In most homes in the U.S. ceiling fans don’t actually save much energy at all, but that’s not to say that they can’t. For all of the reasons that this article has laid out, ceiling fans can be a great money and energy saving tool, but you have to understand how and when to use them. Here are the rules of the road:
- Fans cool people, not rooms. The most important rule of using a ceiling fan to save energy is to turn it off when no one is there. The goal is to make your room feel cooler, allowing you to skip the AC. Ceiling fans don’t actually change the temperature of the room that much, but the circulating air does make the person inside the room feel cooler.
- Use the fan year-round. A ceiling fan set to run counterclockwise in the summer provides a cooling breeze. In the winter, reverse the motor to clockwise (most ceiling fans have this feature) for a gentle updraft, forcing warm air hiding out near the ceiling down. And don’t forget to adjust your thermostat to really realize these savings.
- Apply for a rebate. Energy Star often partners with appliance manufacturers to further incentivize use of energy efficient products. These savings can come in the form of federal tax credits or product rebates. As you continue to make improvements to your home, this website is a helpful tool to discover savings.