How to Choose a Ceiling Fan: Size, Airflow, and Lighting

All you need to do is answer three questions: how big, how fast, and how bright?

I recently installed several ceiling fans in our house – both replacing a light fixture with a ceiling fan and installing a ceiling fan in a room without any existing overhead lighting. Before starting those projects, I distinctly remember searching online at Home Depot, Lowe’s, and Amazon, and being amazed (and almost overwhelmed!) at the quantity and variety of ceiling fans that exist. So I put this guide together to help you quickly and confidently choose the right ceiling fan for your room.

There are three main factors you need to consider when choosing a ceiling fan: its size, airflow, and lighting. In this post, I will explain each one in depth and how they impact which ceiling fans are suitable for your space.

1. Ceiling Fan Size

The size of a ceiling fan is determined by its fan blade span, which is the diameter of the circle that is formed around all of the fan blades – like this:

Ceiling fan with natural, wood-colored fan blades on an off-white ceiling. The fan blade span is indicated by a blue circle with blue arrows
Ceiling fan size is measured by its fan blade span.

Fan blade span is measured in inches, and the reported “size” of a ceiling fan is really its fan blade span. For instance, the 52″ in this description of a Hunter Fan Company ceiling fan on Amazon means that the fan blade span is 52 inches:

A suitable fan blade span is determined by the size of the room where the ceiling fan will be installed. Naturally, smaller rooms need smaller ceiling fans, and larger rooms need larger ceiling fans. Room size is measured in square feet (abbreviated as sq. ft. or ft2), and refers to the area of a room (simply measure the length and width of a room – both in feet – and multiply those two numbers together). Once you know the room size, you can use the below table to get an idea of what size ceiling fan you need:

Room SizeRoom Size DescriptionFan Blade Span
< 100 sq. ft.Small<40 in.
100-200 sq. ft.Medium40-50 in.
>200 sq. ft.Large>50 in.

The last consideration regarding ceiling fan size is that the fan blade span should be at least 30 inches from walls or other obstructions. This generally means that the shorter side of a rectangular-shaped room will often dictate fan blade span. For example, an 8 ft. x 12 ft. room measures 96 sq. ft., but the 8 ft. side of the room can only accommodate a fan blade span that is 36 inches (8 ft. is 96 inches, then subtract 60 inches of total clearance – 30 inches on each side of the fan – leaving 36 inches maximum for the fan blade span). For safety, the fan blades should also be at least 7 feet above the floor.

2. Ceiling Fan Airflow

The next number you need to think about is CFM, which is an abbreviation for Cubic Feet per Minute. This is a measurement of volumetric airflow, and refers to how much air is moved by a ceiling fan (CFM is measured at the fan’s highest speed). The larger the CFM, the more airflow the ceiling fan can generate.

CFM tends to scale with the size of a ceiling fan. A ceiling fan designed to fit in a small room doesn’t need to generate a lot of airflow, so it will have a small CFM. Conversely, a ceiling fan meant for a large room needs to generate a lot of airflow, so it will have a large CFM.

CFM ranges from around 1,500 to over 6,000. All else being equal, if you are choosing between two ceiling fans or looking to narrow down potential choices then choose the ceiling fan with the larger CFM number.

For reference, I installed the following two ceiling fans in our house and have found them both to be perfectly comfortable for the rooms they’re in. This 46-inch ceiling fan has a 2,635 CFM and is in a 117 sq. ft. room:

And this 60-inch ceiling fan has a 4,047 CFM and is in a 324 sq. ft. room:

3. Ceiling Fan Lighting

Lighting for a ceiling fan is determined by the quantity of light bulbs and type of light encasing. The function of the room where the ceiling fan will be installed will govern both of these factors.

A ceiling fan for a room with existing overhead lighting or lots of natural light (like a sunroom) probably doesn’t need its own lighting. Ceiling fans for small/medium rooms or rooms with some existing lighting might need only 2-3 light bulbs to provide sufficient light. Large rooms or rooms with no existing lighting will require 3-4 light bulbs to sufficiently brighten the entire room.

Another consideration is whether the lighting is concealed or exposed. Concealed lighting places light bulbs behind a translucent glass dome/globe, which produces a soft glow that gently illuminates a room while maintaining a warm tone. Concealed lighting will never be as bright as exposed lighting, but can be perfect for rooms where ambient/decorative lighting is desired. This is an example of a ceiling fan with concealed lighting (two light bulbs) behind glass:

Exposed lighting features light bulbs that you can visibly see. This type of lighting provides extremely bright light that spreads across an entire room. For example, this ceiling fan with multi-arm/branched lighting features 3 exposed light bulbs:

Did this guide help you choose a ceiling fan? Have any other questions regarding ceiling fans? Let me know in the comments below!

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