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Trying to decide which ceiling fan to buy but aren’t sure which number of blades is best? Does the number of blades on a ceiling fans matter or is it just a matter of aesthetics? Here’s what you want to know.
The number of blades on a ceiling fan matters as they can affect the sound, amount of airflow, energy consumption and price. In general, fewer (3) blades are better for cheap, energy efficient cooling at the expense of more noise. Fans with more blades (4,5) work well in combination with A/C.
Let’s get into the differences between noise, efficiency, style and airflow to see why the number of ceiling fan blades matters.
Which Number Of Blades Is Best For a Ceiling Fan?
The difference between three and four blades on a ceiling fan is much bigger than between four and five. So the choice is basically between 3 and 4, 5. There is no ‘best’ amount of blades since the blades change different factors. it depends on what you want and expect from a ceiling fan.
Three bladed ceiling fans are generally cheaper, use less energy and move air at a higher speed than fans with more blades. This provides a stronger gust of wind that is better for cooling. However, three bladed fans are noisier and the stronger gust can be uncomfortable.
Ceiling fans with four or five blades generally spin slower and while they might move the same amount of air it moves a bit slower which provides less cooling but is better for distributing air through a space which works especially well in combination with A/C or heating.
Why Does the Number of Blades on a Ceiling Fan Matter?
Ceiling fans with three blades tend to move air at higher speeds to provide a stronger cooling effect while fans with four or five blades provide a gentler flow of air and are quieter at the expense of using more electricity.
Let’s get into why that is and some other differences below.
The number of blades on a ceiling fan has an impact on several things:
One of the biggest differences you’ll notice with different amounts of blades on a ceiling fan is the noise. A ceiling fan with more blades is generally quieter than one with fewer blades. There are a few reasons for this.
The fan with fewer blades will have to (and can) spin faster than a fan with more blades to move the same amount of air. Faster spinning blades mean more turbulence around the edge of the blades and turbulence creates noise.
The motor of a ceiling fan also makes noise. The faster the motor spins, the more noise it makes and fans with fewer blades spin faster since there is less resistance for the motor. A modern, high quality, well designed fan with DC motor will be pretty quiet no matter the amount of blades it has. Especially when not used at max speed, ceiling fans with a DC motor don’t make all that much noise and are pretty affordable nowadays.
That said, for the absolute lowest noise levels, more blades are still a bit better.
Every blade of a fan can almost be seen as a little shovel that throws some air your way. The more shovels you have, the more air you can move. More blades move more air. However, it’s not as simple as that.
While fans with more blades do move more air in general there are a few caveats. If a ceiling fan with more blades would spin as fast as the one with fewer blades, it would move air. However, usually they don’t. Most ceiling fans with many blades have very similarly powered motors to their blade deficient counterparts. Since the blades create drag that the motor has to overcome, the more blades there are, the slower the fan spins.
At lower RPM, the fan with more blades can still move a similar amount of air but the air will be moving slower which feels more comfortable.
What you feel in real life is that a ceiling fan with more blades moves air in a gentler, less choppy way. If feels more constant and not as fast as a ceiling fan with fewer blades. This is more comfortable but doesn’t cool you down as much as the stronger breeze from the fan with fewer blades. It is better for circulating air through a room however.
While fans with more blades move more air, they do require more electricity to do so. More blades add weight and aerodynamic drag that the motor has to overcome. The motor has to overcome this extra drag by using more power. Or more commonly, the motor just spins slower so it has to overcome the same drag as a fan with fewer blades spinning faster.
Adding more blades gives diminishing results. After scooping a bit of air, the blade leaves a low pressure area behind it. If the next blade comes along very quickly behind it, the air pressure hasn’t fully equalized yet and there is simply less air to move. The closer the blades are together the bigger this difference becomes.
The extra blades create some extra airflow but it’s not enough to overcome the added power use. That means per kWh used, a fan with fewer blades moves more air.
If you don’t have A/C and need the most cooling you can get, fewer blades are actually better. While at the same speed, fewer blades move less air, most fans with fewer blades can spin much faster. That means the air moves at a higher speed and this creates a stronger cooling effect.
However, if used in combination with A/C (or heating), a fan with more blades moves air more gently which means no irritating breeze on your skin. More blades are better for distributing air around the room which works well in combination with A/C or heating.
Ceiling fans with more blades are generally better balanced by design. If there is a small difference in blade balancing, it shows up much stronger in a fan with fewer blades. This means
However, many ceiling fans come with balancing kits nowadays to help you make your fan perfectly balanced regardless of the amount of blades. And if you didn’t get one, they’re pretty easy and cheap to get online.
Better balanced fans put less stress on the mounting point, are less likely to loosen up screws and are quieter as well. If you have any imbalance in your ceiling fan, no matter the blade number, its well worth it to spend the couple of bucks a balancing kit costs.
Which style you like is personal but ceiling fans with 4 or 5 blades tend to look better in my opinion. Of course that completely depends on what the rest of your interior looks like and what you like.
There are beautifully designed ceiling fans with only three blades and ugly ones with more blades. It’s more a result of the price range you’re shopping in than a result of the amount of blades. Ceiling fans with more blades are generally a bit more expensive and the better looks are a side effect that comes with this.
Blade Size Can Determine How Well Your Fan Works for Your Space
The number of blades isn’t the only consideration when buying a ceiling fan. The size has a very big impact as well, bigger than the amount of blades. Increasing the length of the blade helps push dramatically more air per revolution of the fan.
Longer fan blades are more effective for cooling down larger rooms because they circulate the air more widely. Rather than pushing the air down, longer blades will help push the air around the room, covering more space.
Smaller blades don’t allow the air to be pushed around the room as much. Rather than swirling the air around, small blades push the air down, allowing it to more effectively cool smaller spaces like bedrooms.
Longer blades are more effective for cooling large areas like your living room or even outdoor spaces. Keep smaller blades for smaller areas like a bedroom, bathroom, or even smaller gathering areas.