Maximum Ceiling Fan RPMs
Published by: Greg Tillotson
Webmaster for Hansen Wholesale
Ever wonder why ceiling fans only go so fast? Ever think that if manufacturers just made ceiling fans spin faster, they would move more air? Well, maybe you don't think of these kinds of things, but as the webmaster for the Largest Ceiling Fan Website online, I can't help but have such thoughts.
The fact is: There are UL standards that place limitations on ceiling fan manufacturers that prevent them making fans that spin too fast. These limitations for safety purposes and are meant to minimize the risk of injury should a person raise their hands (or any other object) into the path of the ceiling fan blades while the fan is in operation. Imagine if some ceiling fan blades moved as fast as an airplane propeller and had blades like a machete! Well, UL standards prevent manufacturers from making such products...but they also present challenges to engineers who attempt design ceiling fans for maximum airflow and efficiency.
Maximum RPMS Allowed for Ceiling Fans
The first basic limitation is that no residential ceiling fans are allowed to be installed such that the blades are less than 7 feet from the floor. The second basic limitation has to do with the RPMs at which a fan can spin relative to the thickness of the blades. The concept is that thinner blades can cause more damage of laceration, so they are not allowed to spin as fast as those with thicker blades.
The RPMs allowed for any residential ceiling fan that can be installed on a ceiling less than 10 feet high are restricted by UL based on the blade span and thickness of the blades (see chart below). Any blade less than 3/16" thick cannot exceed the RPMs for 1/8" thick blades. Any blades 3/16" thick or greater cannot exceed the RPMs for 3/16" thick blades. In no case can the fan blades be less than 1/8" thick. No ceiling fan is allowed to be installed with the blades closer than 7 feet from the floor. These limitations are in place to minimize the risk of injury should a person raise their hands (or any other object) into the path of the fan blades while the fan is in operation.
How do RPMs affect airflow?
The amount of air that a ceiling fan produces is certainly affected by how fast is spins. Yet RPMs alone do not produce airflow. The aerodynamics of the blades is every bit as important as the RPMs. If a fan has blades that are straight and flat, it doesn't matter how fast it spins, it's not going to generate much airflow. Take the same blades and give them a 15 degree pitch and the fan will move air, but the RPMs will be slower since the angled blades are now having to perform some work, which puts drag on the motor. You can equate this to the difficulty of rowing a boat when you place the oars flat in the water compared to turning them at an angle. Flat is easy to row, but will not get you anywhere. Angling the blades just a few degrees makes it more difficult to row the boat, but you actually start moving. So imagine the difference in airflow between 2 fans that operate at the same RPM yet one has flat blades and the other has angled blades. The fan with angled blades must have a more powerful motor in order to maintain the same RPM as the fan with flat blades. So judging the airflow performance of a fan strictly by comparing RPMs is of little value. What you really need to know is how much airflow the fan will produce when operating at a particular RPM.
Maximum RPMS Reference Chart
The data below is based on ceiling fans that have a reverse function. Non-reversing ceiling fans are allowed to have slightly higher RPMs. UL actually states the limitations based on the maximum allowed speed of the tip of the fan blade at 3200 feet/minute for 3/16" thick blades and 2400 feet/minute for 1/8" thick blades. We have provided the following data by creating a formula that does this calculation based on the overall bladespan of any particular ceiling fan ranging from 24" to 84".
Based on UL 507 Standards (link to PDF removed by request of UL - 5/30/2013)
|Span||3/16" Thick||1/8" Thick
Answers to Recent Ceiling Fans Questions Posted To This Page
- Question #9503 - Posted: 7/6/2014 9:23:16 AM
Ceiling Fans Question - Minka Aire Model F820-CT
F820-CT - http://www.hansenwholesale.com/ceilingfans/minkaaire/model.asp?ProdNo=F820-CT
QUESTION: I want to purchase the 36" Down rod DR536-CT (Cattera Bronze finish) $25.13 for the Santa Lucia Ceiling Fan I recently purchased from you. However, when I try to select it the website automatically adds the fan too. Please help
Sorry you are having trouble ordering a downrod. Here is what you can do: Simply delete the fan from your shopping cart to order just the downrod or use this link to add the downrod to your cart by itself:
Minka Aire DR536-CT Downrod
- Question #9502 - Posted: 7/6/2014 9:17:41 AM
Ceiling Fans Question
QUESTION: Do you happen to carry Hunter fan light fixtures that have a triangle base. These are not held in by screws but by a clip system.
ANSWER: I am sorry to report that we do not have any of the Hunter light fixtures you are looking for. Hunter only made the triangular fixtures for a short period of time and they discontinued them several years ago (too many problems). It is unlikely that you will be able to locate one anywhere. If you can email me some pictures of your fan along with the model number (located on a label on top of the fan housing), I may be able to come up with an alternative that will fit. Email your pictures to: firstname.lastname@example.org
- Question #9500 - Posted: 7/3/2014 1:55:05 AM
Ceiling Fans Question - Modern Fan Model VEL-HUG-BN-50-NK-NL-NC
VEL-HUG-BN-50-NK-NL-NC - http://www.hansenwholesale.com/ceilingfans/modernfan/model.asp?ProdNo=VEL-HUG-BN-50-NK-NL-NC
First off, I love all the consumer information Hansen Wholesale provides.
I'd love a clarification on something. You say that hugger fans don't work as well as regular ceiling fans. This makes total sense. However, why would the Modern Fan Velo Hugger be rated at the same 6650 CFM and 5.54 MPH wind speed as the regular Velo?
(Is it because the blades are installed as low as possible on the hugger fan, thus negating the height benefits?)
ANSWER: You are exactly correct. When installed with a standard downrod, the regular Velo hangs down the same distance as the Velo Hugger, so the airflow is the same.
- Question #9499 - Posted: 7/2/2014 11:30:33 PM
Ceiling Fans Question - Savoy House Model SV-58-819-5WA-37
SV-58-819-5WA-37 - http://www.hansenwholesale.com/ceilingfans/savoyhouse/model.asp?ProdNo=SV-58-819-5WA-37
Per the information on the site, the new DC motors, the Emerson K55XL, and other "induction" type motors are considered best quality. If that's the case, how do fans with smallish non-special motors (Say, Savoy House Indira, with 153 x 22mm motor) earn a 5 rating?
There are exceptions. A 5 rating is not just based on the motor inside the fan, but the overall consideration of the quality of the components and performance. Most 153mm motors are only 12mm to 15mm tall and tend to be overworked. The motor used in the Indra is 22mm tall, which is very unusual. This is a special motor that Savoy House had designed for this fan and the performance and quality of the motor are excellent. The 3-blade Indra produces a whopping 8517 CFM and runs very smooth and quiet. The entire fan was designed to produce maximum airflow while reducing noise. The blades have a very special aerodynamic design and the fan runs perfectly quiet. When I saw this fan introduced at the lighting show in Dallas, I was very impressed. Overall, one of the best fans I have rated in years. A DC motor would have been nice...but was not necessary to earn a 5 in my book.
Here is a link to the Savoy House Indra
- Question #9496 - Posted: 6/19/2014 10:09:09 AM
Ceiling Fans Question - Minka Aire Model F513-WH
F513-WH - http://www.hansenwholesale.com/ceilingfans/minkaaire/model.asp?ProdNo=F513-WH
QUESTION: Hi, I have 4 rooms I'm thinking of installing fans. One is 10x14, 2 are 13x14, and a fourth is 23x15. For the first 3 I was considering Minka Aire F513. For the largest room I was thinking about Minka Aire MF-689. Will these be adequate?
Thanks, Tom Kelley
The Minka Aire F513 New Era fans will be great for the 3 smaller rooms. For the larger room, a single ceiling fan will not be adequate...you should install 2 fans. If you install 2 fans, then the F689 Kola-XL 60" fans would be a great choice. If you can only install a single fan, then I would recommend an even larger fan (up to 84") such as the Fanimation Odyn. Here are links to those resources: Large Ceiling Fans
or The Fanimation Odyn
. Please call us at: 1-800-201-1193 and we will be happy to discuss all of your options and help you make an educated decision.
- Question #9495 - Posted: 6/19/2014 9:59:26 AM
Ceiling Fans Question
QUESTION: for a DC fan I must use solar power, I am looking for a very efficient fan around 72 inch for a vaulted living room, I have 3 sky lights, I can use one for solar, if I go this way what is the ball park figure for the solar unit for the fan., and how does it work at night. or should I get a very efficient ac ceiling fan
All of the ceiling fans we sell are made to connect to AC current and there are no options to convert them to DC current from solar power. So for high efficiency, we would recommend any of our DC ceiling fans, but connected to AC current. Here is a link to all of our Ceiling Fans with DC Motors
. For a super efficient DC fan without a light, I would recommend the Fanimation Keystone
. Otherwise, just give us a call and we will be happy to help you choose the best fan for your application.
- Question #9494 - Posted: 5/10/2014 3:26:40 AM
Ceiling Fans Question - Kichler Model KL-300146AP-37027OBB
KL-300146AP-37027OBB - http://www.hansenwholesale.com/ceilingfans/kichler/model.asp?ProdNo=KL-300146AP-37027OBB
QUESTION: The kitchler 58" arkwright fan with plywood blades. Your polished version with poly blades shows that it has plywood blades and a light. Your pewter with plywood blades says it has no blades and that no light is avail? The page also says there is an error with the blades? Does the polished version version listed as poly blades have the plywood blades and the light as listed? Does the pewter version with plywood come with the blades and does it include the light or is there one avail? Prices?
ANSWER: Sorry for the confusion regarding the Kichler Arkwright fans, we did have some errors which I have now fixed. The bottom line is, the Kichler Arkwright fans come without blades or lights so you can pick and choose whichever combination suites your taste. We named them "Plywood" or "Polycarbonate" only to differentiate between what is shown in the pictures. But you can get any of the motor finishes with any of the blades (size, material or finish) with or without a light. The pictures and model numbers we created are just a few examples of the possible combinations.
- Question #9493 - Posted: 5/8/2014 9:00:50 AM
Ceiling Fans Question - Casablanca Model CA-54101
CA-54101 - http://www.hansenwholesale.com/ceilingfans/casablanca/model.asp?ProdNo=CA-54101
QUESTION: Will remote automatically work with this fan or will I have to do any rewiring? The ceiling fan I have is worried directly and not to a wall switch.
ANSWER: This remote is only designed to work with specific Casablanca ceiling fans, so the answer depends on the fan that you already have. The receiver wires into the canopy at the ceiling. No extra wiring is necessary to install the receiver aside from connecting it to the existing ceiling wiring and to the fan wiring. Please contact us to discuss your particular fan model.
- Question #9492 - Posted: 5/8/2014 8:47:59 AM
Ceiling Fans Question - Emerson Model CFB65-2000-AB
CFB65-2000-AB - http://www.hansenwholesale.com/ceilingfans/emerson/model.asp?ProdNo=CFB65-2000-AB
QUESTION: can i use the b65dm dark mahogony bentwood blades with the CF 2000ORB housing and motor. It would require ORB connections from blade to motor.
ANSWER: No, these blades will only fit the Emerson Maui Bay ceiling fan blade holders. They are not made to work with any other model or brand. Not only because they will not fit, but the fan motor must be designed to handle the additional torque that larger blades like this create. Most blades are not interchangeable between models or brands.