Staying cool is important but so is keeping your energy bill affordable. Is there a difference in how much electricity ceiling fans use and what is the most efficient? Here’s what you want to know.
There are large differences in energy efficiency of ceiling fans with some being up to 70% more efficient than others. A ceiling fan with DC motor provides a big efficiency improvement over one with AC motor. Other factors that improve efficiency are size (bigger is better) and amount of blades.
What amount of blades is better and what makes a ceiling fan more efficient? Find out below.
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Are Some Ceiling Fans More Efficient Than Others?
Ceiling fans are all built in roughly the same way. There is a motor which spins the fan assembly. How much difference can there be? Actually, there is quite a bit of difference not only in design and quality but also the energy consumption of ceiling fans.
Some ceiling fans can be as much as 70% more energy efficient than others. So paying attention to a few factors we’ll go into below can make an impact on your energy bill. Usually more efficient ceiling fans are also a little higher quality so that’s a nice added bonus. Of course those fans do cost a bit more as well.
The most efficient ceiling fan is not necessarily one type of fan. Two fans that look very different can both be more efficient than average while two fans that look the same can have very different efficiencies. There are some things you can look for while shopping that can help you pick an energy efficient fan that fits your needs.
Also check out this article: How much power does a ceiling fan use?
How To Measure Ceiling Fan Efficiency
So how can you measure or know the energy efficiency of a ceiling fan? Buying them all and measuring how much energy they use isn’t a great use of time or money.
Luckily most manufacturers will list how many Watts it consumes. However, that’s not a great way of measuring efficiency. One fan can produce much more airflow with the same power consumption than another one.
Luckily there is a better measurement that’s also often available and that’s CFM/W or cubic feet a minute per Watt. So how much airflow every Watt produces. That’s a much better measurement of energy efficiency than total energy consumption. A ceiling fan is about producing airflow to begin with so measuring efficiency by airflow makes sense.
You can often find the CFM/W rating and max airflow ratings of ceiling fans by looking at the listing on Amazon. You can find more information about this in this post:
How much power does a ceiling fan use?
What Makes A Ceiling Fan Efficient?
Besides the CFM/W rating, what are some other indicators that a ceiling fan just sips electricity? There are some things you can see by just looking at a ceiling fan and listing that can make as much as a 70% difference in energy consumption. Here’s what you can look for:
- DC motor
- Size
- Number of blades
Let’s look at these things and how they impact energy efficiency.
DC motor
Many newer and/or higher quality ceiling fans have a different type of motor. There are AC and DC type electric motors. Those types exist across all types of electric motors and ceiling fans are no different. If you want to know the exact differences are click here.
DC motors and specifically brushless DC motors are built in a way that uses up to 65% less electricity than a comparable AC motor. This is obviously a huge savings and will be noticeable. It’s the first and most important thing you should look for when buying a ceiling fan.
And energy efficiency isn’t the only reason why DC motors are better. They are also less noisy than AC motors. Less noise while staying cool and having a lower electric bill sound like a pretty good things.
It’s usually not very difficult to spot a ceiling fan with DC type motor. It’s usually advertised openly and clearly. Manufacturers surely want you to know that their fan uses less energy so it won’t be difficult to find. Of course the manufacturers will also charge you a little extra money for the better components. The price difference isn’t huge and most higher quality fans will have the DC motor nowadays but it’s still worth checking.
Will you make back the difference in price because of the higher efficiency? Not very quickly. Ceiling fans don’t use that much electricity to begin with so even while saving 65%, it’ll take a while to make the money back. However, more efficient appliances are always good. And a good ceiling fan can last 10+ years and in that amount of time, it’ll be worth it.
Size
Fans with a larger diameter tend to be more energy efficient. A larger diameter fan means a bigger blade. Bigger blades can scoop more air in one rotation than a smaller blade. While it does cost more electricity to spin a bigger fan, the increase in airflow is larger than the increase in energy consumption so the efficiency is higher, especially at lower speeds.
Suggested: Are short blade ceiling fans any good?
In most cases, the max airflow of a larger ceiling fan is higher than the max airflow of a smaller fan. However, you only need a certain amount of airflow. That means you can run the bigger fan at a lower speed and still have enough airflow.
Of course, you can’t freely choose the size of fan you put in your room. A fan that’s too big won’t fit and/or have enough clearance. A fan that’s too small might not be able to produce enough airflow. Choosing the right size fan for your room and application is important. However, by going one size bigger than necessary (if it fits) is going to increase your efficiency a little.
Number of blades
The number of blades on a fan does have an impact on the efficiency of a fan. And it might be a bit different than you expect it to work. Fewer blades actually makes a fan more efficient.
Fewer blades means the blade assembly is lighter and has less aerodynamic resistance. Yes, more blades will move more air if they would be spinning at the same speed as a fan with fewer blades however, the amount of extra electricity this requires means the fan has a lower CFM/W rating.
Suggested: Is a fan with 3 or 4 blades better?
However, there are also some good reasons to go for a fan with more blades even if it costs a bit of efficiency. A fan with fewer blades will spin faster with the same amount of power put in and move more air. Because it spins faster, it also creates more airspeed. It will feel more like the direct airstream of a pedestal fan. If that’s a good thing is personal preference. However, this also creates more noise.
In many cases, a ceiling fan is used in combination with A/C to help circulate the cool air through the room. This means you don’t need a very strong direct stream of air to cool down. A fan with more blades can spin slower and just create air circulation with much less noise which is more important than a tiny bit of efficiency for most people.
