Air Curtains 101: How Berner Air Curtains Work

What is an Air Curtain?

Air Curtains 101: An air curtain, also known as an air door, employs a controlled stream of air aimed across an opening to create an air seal. This seal separates different environments while allowing a smooth, uninterrupted flow of traffic and unobstructed vision through the opening. Because air curtains help to contain heated or conditioned air, they provide sizable energy savings and increased personal comfort when applied in industrial or commercial settings. Air curtains also help to stop the infiltration of pollutants and flying insects.

Air Curtains 101

Animated info graphic of how an air curtain works

How Does an Air Curtain Work?

  1. Once the air curtain is powered on, air is brought into the unit through the intake
  2. The air then enters the fan housing and is accelerated by the fan.
  3. This fast-moving air goes into a plenum, which allows for an even distribution of air along the full length of the discharge nozzle.
  4. Airfoil-shaped vanes in the nozzle create a uniform air stream with minimal turbulence.
  5. The air discharged through the nozzle creates a jet stream to the floor. Approximately 80% of the air returns to the intake side of the air curtain, and 20% goes in the opposite direction.

Why Use an Air Curtain?

  • Energy savings through control of air transfer
  • Energy savings due to shorter run times of air handler or compressor
  • Maintain employee/customer comfort
  • Reduce flying insect infiltration
  • Unhindered traffic flow
  • Unobstructed visibility across the threshold
  • Increase productivity due to stable temperatures
  • Maintain usable space around the door
  • Elimination of ice and fog in cold storage areas

Air Curtain Pro Tips

There are two major types of air curtains: non-recirculating (most common) and recirculating.

Non-recirculating Air Curtains

Non-recirculating air curtains are more widely used than the recirculating type because they are easier and less expensive to install and have lower maintenance costs.

The height, width, and physical characteristics of the opening will indicate if the air curtain can be mounted horizontally above the door or vertically on one or both sides of the door. A horizontal mounting above the door minimizes the chances of damaging the air curtain. Use caution when mounting a unit vertically.

Recirculating Air Curtains

Recirculating air curtains are typically used in places with constant foot traffic such as supermarkets and store entrances. Berner’s recirculating air curtains are called Air Entrance Systems, as they are built into the entrance, usually when the entrance is being constructed. They emit air from a discharge grille on one side of the door opening, collect it through a receiving grille on the opposite side and returning it through duct-work to the discharge grille. The non-obtrusive wide stream of low-velocity air created by recirculating air curtains is more desirable for separating environments.

Air Curtain Maintenance

Berner air curtains require minimal maintenance. Scheduled cleanings of your air curtain at least once every three months will ensure that it works properly and will also extend the life of the unit. Extremely dirty, dusty, or greasy environments could require a more aggressive cleaning schedule.

For efficient air curtain performance, setting the angle of the discharge nozzle correctly is crucial. An air curtain nozzle should be adjusted to aim inward or outward up to 20 degrees from the opening.

To select the proper size, power rating, and features for a particular air curtain application, consider the following:

  • The physical dimensions of the opening, including height, width, and space available for installation (clearance above the mantle).
  • The type of door intended for installation.
  • The type of opening — customer entry, service entry, dock door, etc.
  • The climate. Would building occupants appreciate supplemental heat at the door?
  • The prevailing winds and exterior temperatures on outside openings.
  • The existence of any drafts due to pressure differences at the opening.

How To Clean an Air Curtain

To clean an air curtain, begin by turning off the power at the service panel. Once off, ensure the unit does not turn on during cleaning by locking the panel, as well.

Next, remove the air intake grille for access to the blower housing and motor(s). Remove the bottom access panel on heated models for access to the blower housings and motor(s). Vacuum and scrape (if necessary) to remove the built-up dirt and debris. For instructions for your particular model, consult the appropriate installation instructions.

History of the Air Curtain

Air curtains first came to the U.S. in 1904 when Theophilus Van Kannel received the patent for one. According to records, however, the first air curtain installation in the States wasn’t until 12 years later. In Europe, air curtains were becoming increasingly popular during the late 1940s and 1950s. Then, in 1956, Erling Berner brought the most advanced European air curtain technology to the United States and formed Berner Industries, the foundation of today’s Berner International. Used over cold storage doorways, the first Berner air curtains were manufactured and sold in 1960.

Continuing Education

To learn more about air curtains, take the free AEC Daily continuing education course online: “Air Curtains: Energy Savings & Occupant Comfort.”

This is an approved AIA course (1.0 LU/HSW hour), and it also qualifies for GBCI, RCEP, and many other organizations’ continuing education requirements.