Good CFM for a ceiling fan is 3,000 to 5,000 for most common room sizes.
Tip: A good ceiling fan size is one with a CFM that matches room size. It shouldn’t have too many or too few CFM for the space. This is explained below.
- A good CFM for a ceiling fan in a 12×12 room is 3,000 CMF, which you get with a 44” ceiling fan. And good CFM for a ceiling fan in a 20’x20’ room is 5,000 CFM.
- Very small rooms need 1,000 to 2,000 CFM.
- Rooms greater than 400 square feet, or about 20’x20’, should have ceiling fans with 5,000 to 9,000 CFM.
This page answers the questions of what size ceiling fan you need for your room size and how the number of fan blades affects airflow CFM.
How Many CFM Ceiling Fan Do I Need?
Ceiling fans range in airflow from less than 1,000 CFM to more than 10,000 CFM.
It is important to properly size the fan or:
- Too little CFM: You won’t get enough airflow, and the room will remain warm in summer without a gentle breeze. In winter, the room might be cool, because the heat will rise and not be circulated back down by a fan that is too small.
- Too much CFM: You’ll have too much, creating a disruptive breeze, and it will be noisy too. Plus, it will waste energy.
This chart shows room square footage, the appropriate size fan for the space, and the amount of airflow in CFM those fans deliver.
CFM = cubic feet per minute. It is a rating that all ceiling fans have, so consumers will know if the fan they are considering is the right size for their needs.
How Many CFM Ceiling Fan Do I Need
|Room Size (sq ft)||Suggested Fan Size||Suggested Airflow|
|< 75||29 – 36″||1000 – 2000 CFM|
|76 – 144||36 – 42″||2000 – 3000 CFM|
|144 – 225||44″||3000 – 3500 CFM|
|225 – 400||50 – 54″||3500 – 5000 CFM|
|> 400||56 – 72”||5000 – 9000 CFM|
Information from the US Department of Energy and other sources was used to compile the chart.
Do More Fan Blades Mean More Airflow?
Yes. More fan blades mean more airflow. But there are a few exceptions as seen in the Chart below.
More ceiling fan blades equals higher CFM for two reasons:
First is the obvious. A fan with more blades moves more air than a comparable fan of the same motor power and blade length with fewer blades.
Secondly, fans with more blades are usually more powerful. They have larger motors that can handle the drag created by more blades. For example, you won’t find many 44” fans with more than 5 blades. And you will find only a few 60” to 72” fans with less than 5 blades, though there are some.
|Number of Blades||AVERAGE Airflow (CFM)|
Note: This data is based on 500 popular ceiling fans sold by Home Depot.
The information is consistent with data from all major ceiling fan manufacturers including Hunter, Minka-Aire, Fanimation, Westinghouse, Home Decorators Collection, Hugger and Hampton Bay.
Average Airflow: Note that the right column is the average CFM for ceiling fans with those numbers of blades. You can find higher CFM fans in most sizes.
For example, our research shows that there are several ceiling fans with 4 blades that have airflow over 5500 CFM. And 7 blade ceiling fans can have airflow over 7,000 CFM.
How Many Ceiling Fan CFM Per Square Foot?
An analysis of the data shows that you need between about 12 and 25 CFM per square foot.
Secondly, the smaller the room, the more CFM per square foot is common. This is partly because the smaller fans produce more CFM relative to their size than large fans.
As a result, once the room gets to be 200 square feet or more, the CFM per square foot begins to drop to 15 or below.
Ceiling fan CFM to room square feet examples:
* A 144 square foot room needs a 3,000 CFM fan. 3,000 divided by 144 equals about 21 CFM per square foot.
*In comparison, 400 square feet needs a 5,000 CFM fan. That’s 12.5 CFM per square foot.
What is the Average Ceiling Fan CFM?
Analysis of 500 ceiling fans shows that the average CFM is 4,000 to 6,000. They’re a perfect fit for rooms from 15’x15 (225 sq. ft.) to 24’x24’’ (576 sq. ft.).
Do You Need More Ceiling Fan CFM Outdoors?
Yes. If you are going to install your ceiling fan on a porch, pergola or other covered outdoor space, select a fan with a CFM at or near the upper end of the ranges in the chart above.
For example, if you have a 15’x20’ porch, or 300 square feet, your recommended fan size for that square footage is 3,500 to 5,000. Select a fan between 4,500 and 5,000 for the area.
Does Ceiling Height Make a Difference in Choosing Fan CFM?
Yes, somewhat. First, the problem of a higher ceiling can be eliminated by choosing the right downrod for the application.
However, if the ceiling is quite high and the downrod isn’t long enough, you should choose a fan that is larger than required for the number of square feet.
For example, in a 20’x20’ room with a very high ceiling and a downrod that hangs the fan more than 12’ from the ground, consider fans with 5,500 to 7,000 CFM.
What Else Affects Ceiling Fan Airflow?
The pitch and shape of the fan blades will also affect CFM. A steeper pitch – more slant to the blade – will generally push more air. And wider, slightly concave blades might also increase airflow.