Large Diameter Ceiling Fans


Ceiling fans are a type of circulating fan that provides air mixing, destratification, and cooling effect for comfort for residential, commercial, industrial, and agricultural applications.

This web page covers regulation and guidance for large diameter ceiling fans (LDCF), which are a product class defined by the U.S. Department of Energy having a blade span (diameter that includes wing tips) greater than 7-ft. (2.1-m). LDCF include high-velocity, low-speed (HVLS) fans, but some LDCF do not have HVLS properties.

Small diameter ceiling fans are broken into subcategories first by speed (high-speed/small diameter – HSSD) and (low-speed, small diameter – LSSD), but are not covered by this web page.

This webpage covers LDCF includes guidance on how to operate HVLS fans to reduce COVID-19 exposure in U.S. warehouses.

Reduction of COVID-19 Exposure in Warehouses with HVLS Fans


Air Movement and Control Association (AMCA) International, in collaboration with Concordia University and a team of engineers and scientists, has released the results of a year-long study of the impact of large-diameter (greater than 7 ft [2.1 m]) ceiling fans on coronavirus disease 2019 (COVID-19) exposures in warehouses in the United States.

Applicable to large open indoor spaces with low occupancy in addition to warehouses, the findings are based on more than 220 parametric computational-fluid-dynamics (CFD) simulations varying worker and packing-line locations and fan speed (20 percent to 100 percent) with and without racking. The fans used in the project are certified by AMCA International for air performance.

Detailed Information

For information on the simulation methodology, setups, assumptions, validations, and results of the study, see the final report, “AMCA COVID Guidance for UNDUCTED Fans – Modeling Ceiling Fans,” at For a summary technical article published in the 2021 edition of AMCA inmotion, click here.

Summary Guidance

  • Operate fans at the highest feasible speed while maintaining occupant comfort in the space.
  • Where possible, avoid locating occupants immediately downstream of each other for extended periods of time.
  • At high fan speeds (e.g. summer conditions) the simulations show a notable reduction in concentrations.
  • At low fan speeds (e.g. winter conditions) the simulations show a slight reduction in concentration in the region close to the fan (e.g. within three fan diameters), and no practical difference outside that region.

Project Roster

AMCA wishes to thank Liangzhu (Leon) Wang, PhD, P.Eng., and his team at Concordia University for the modeling and the science and industry teams for their contributions to the study design and the review of the results and guidance.

AMCA also thanks member companies Big Ass Fans, Greenheck Fan Corp., Hunter Industrial, and MacroAir Technologies for co-funding the study with AMCA International.

To promote integrity in the design and execution of the research and ensure the conclusions drawn from the study are valid and useful, AMCA International assembled industry and science teams. Consisting of representatives of AMCA International member companies and members of the AMCA International staff, the industry team provided expertise in the application and performance of products, while the science team, made up of authorities on infectious diseases, indoor-air quality, fans, and computer modeling, advised on the project setup and reviewed the intermediate and final results. The table below identifies the rosters of the science and industry teams.

Table: Science and Industry Teams for AMCA LDCF COVID Guidance Research

Science Team

Liangzhu Wang, PhD

Associate professor, Department of Building, Civil, and Environmental Engineering

Concordia University

William P. Bahnfleth, PhD, PE, FASHRAE

Professor, architectural engineering,

Chair, ASHRAE Epidemic Task Force

The Pennsylvania State University

Edward. Nardell, PhD

Professor, departments of Environmental Health and Immunology and Infectious Diseases

Harvard T. H. Chan School of Public Health

Jovan Pantelic, PhD

Research scientist, building science

Well Living Lab Inc.

Paul Raftery, PhD

Professional researcher

Center for the Built Environment University of California, Berkeley

Geoffrey Sheard, PhD


AGS Consulting

Pawel Wargocki, PhD

Associate Professor, departments of Civil Engineering and Indoor Environment

Chair, ASHRAE Epidemic Task Force Science Applications Committee

Technical University of Denmark

Industry Team

Michael Ivanovich

Senior Director, Global Relations

AMCA International

Eddie Boyd

President and CEO

MacroAir Technologies

Marc Brandt

Director, Domestic Industrial Business

Hunter Industrial

Thomas Catania, Esq.

Board Member

Institute for Energy Innovation

Aaron Gunzner

Senior manager, advocacy

AMCA International

Mark Stevens

Executive director

AMCA International

Christian Taber

Principal engineer, codes, and standards

Big Ass Fans

Mike Wolf

Director, regulatory business development

Greenheck Fan Corp.

Find out more about testing Large Diameter Ceiling Fans with the AMCA laboratory.

Video of July 21 Webinar—AMCA insite Webinar- U.S. Codes, Standards, and Regulations for Large Diameter Ceiling Fans

Introducing the LDCF Ceiling Fan Energy Index (CFEI)

AMCA White Paper: Introducing Ceiling Fan Energy Index (CFEI) and Changes to the U.S. Regulation for Large-Diameter Ceiling Fans. You can read or download the white paper here!

This white paper describes how the Ceiling Fan Energy Index (CFEI) metric was developed for large-diameter ceiling fans (LDCF)and how it came to replace the U.S. Department of Energy's metric, DOE cfm/W. in the U.S. Code of Federal Regulations. The white paper also describes an erratum for ANSI/AMCA Standard 230-15, which is referenced in the DOE test procedure for LDCF and how AMCA tests and certifies LDCFs. The white paper also provides hyperlinks to online resources for the DOE LDCF regulation.

Recent U.S. Dept. of Energy Actions

  • December 27, 2020: The Federal Omnibus Bill signed by President Donald Trump contained the Energy Act of 2020, which contained the Ceiling Fan Improvement Act in Section 1008. The Act changes the cfm/W regulatory metric for LDCF to Ceiling Fan Energy Index (CFEI).

  • May 5, 2021: A “Technical Erratum Notification” was issued by AMCA International for ANSI/AMCA Standard 230-15, Laboratory Methods of Testing Air Circulating Fans for Rating and Certification, which is referenced in the DOE test procedure for LDCF. The erratum corrects the electrical input power measurement to standard air density.

  • May 7, 2021: DOE Publishes Request for Information for "Early Review" of Ceiling Fan Energy Standard—The U.S. Department of Energy (“DOE”) is undertaking an early assessment review for amended energy conservation standards for ceiling fans to determine whether to amend applicable energy conservation standards for this product. Specifically, through this request for information (“RFI”), DOE seeks data and information to evaluate whether amended energy conservation standards would result in significant savings of energy; be technologically feasible; and be economically justified. Written comments are due June 5, 2021 (recently extended to June 28) from the public on any subject within the scope of this document (including those topics not specifically raised in this RFI), as well as the submission of data and other relevant information concerning this early assessment review.

  • May 27, 2021: DOE published the CFEI codification of the Ceiling Fan Improvement Act in Federal Register, thereby integrating CFEI into the Code of Federal Regulations and removing cfm/W for LDCF.

  • June 3, 2021: DOE Extends Deadline for Ceiling Fan RFI to June 28, 2021—Per a request from AMCA International and American Lighting Association, and with a letter of support from Appliance Standards Awareness Project and Northwest Energy Efficiency Alliance, DOE granted an extension of the June 5 deadline to June 28, 2021.

For more information, contact Michael Ivanovich at AMCA International.

Air Movement and Control Association International, Inc.