An air curtain is a device that creates a continuous stream of air across a doorway to separate two environments. It’s designed to reduce the movement of heat, dust, and airborne particles without physically closing the opening. While the concept is straightforward, performance depends on airflow strength, consistency, and installation.
How an Air Curtain Works
Despite the name, an air curtain is actually a device that creates an invisible barrier of high-velocity air over an entryway or between two spaces. This barrier effectively separates different environments without the need for physical doors. The primary components of an air curtain include:
- Blower fans to generate a consistent stream of air
- An air nozzle or plenum that directs the airflow uniformly across the opening
- Control systems that allow for adjustments in airflow speed and temperature
When activated, the air curtain discharges a controlled stream of air, forming a barrier that minimizes the infiltration of unconditioned air, contaminants, and pests.
Where Air Curtains Are Commonly Used
Ever worked in a restaurant that had a walk-in cooler or freezer? Have you ever been in a laboratory with cold storage? Businesses like these need efficient ways to get in and out of cold storage without wasting energy or compromising the temperature of that room. You wouldn’t want fresh produce or the active ingredients in a medication to spoil. A traditional door lets in air contaminants and can also compromise the temperature in these kinds of spaces.
But other businesses benefit from this efficient way to separate the environments of different rooms as well. Air curtains are frequently used in:
- Commercial Entrances. Those rows of double sliding glass doors in retail stores, supermarkets, and shopping malls would absolutely sink a company in heating and cooling costs, not to mention let in all kinds of pests, dirt, and debris if air curtains on either side didn’t stop them.
- Industrial Facilities. Air curtains are used in warehouses and manufacturing plants to separate different temperature zones and prevent cross-contamination.
- Cold Storage Facilities. Air curtains are put to great use in refrigerated rooms to minimize temperature fluctuations and reduce energy consumption.
- Food Service Establishments. These are commonly found in restaurants and food processing units to deter flying insects and maintain hygiene standards.
- Healthcare Settings. We also see air curtains used in medical contexts. They can be used to separate sterile and non-sterile areas in hospitals and laboratories, reducing the risk of contamination.
- Zoos and Botanical Gardens. If you’ve ever been to a botanical garden, a butterfly conservatory, or an aviary, you’ve probably seen air curtains there as well. Tropical birds or plants do not mix well with those from the desert. Often, in places like these with living creatures, they will even use double air curtains to ensure people don’t accidentally let a bird or a butterfly into the adjoining room.
What Air Curtains Are Designed to Do
Now, for any one of the above examples, think about the alternative — a traditional door, no blowers. This door may be heavy-duty and have great insulating qualities. But still, there’s always the few seconds between pulling that door open, walking through, and letting it swing closed behind you, that you are mixing climates between the two rooms. This isn’t good for overall energy efficiency, and with special products like produce, medication, plants, birds, and insects, there is definitely a higher chance of putting these things at risk in just those few seconds.
Some other quick points on the advantages of air curtains in commercial doorways:
- Lower energy costs because of control of air transfer between spaces
- Lower overhead costs due to the building’s HVAC system working less hard, which means less use, less wear and tear, less maintenance, and
- lower utility costs
- Increasing ventilation and air circulation creates a better environment for people in the building
- Free traffic flow between spaces, ADA-friendly
- Uninterrupted lines of sight, inviting feel for storefront doors
- Reduced CO2 emissions
- Greatly reduces smoke transfer in cases of fire emergencies
- More available space on storefront entryways
Even if you have a breezeway with a door on each side to separate the spaces, you’re still losing temperature and humidity in that space between the doors. Air curtains and their overhead blowers drastically reduce energy loss and contamination risk. Thinking about it, you’ve probably seen them all over the place but weren’t aware of why. Now that you know, maybe the utility of an air curtain is something you might consider for your business.
What an Air Curtain Doesn’t Do
Air curtains are sometimes misunderstood as a complete replacement for doors or sealed barriers. In reality, they reduce air exchange but don’t eliminate it. They also won’t:
- Create an airtight seal
- Fully block extreme weather conditions
- Compensate for improper sizing or installation
Performance can also vary depending on environmental factors like wind pressure and temperature differences. Understanding these limitations helps prevent overestimating what the system can achieve.
Different Types of Air Curtains
The two major types of air curtains are recirculating and non-recirculating. Non- recirculating air curtains are the most popular, as they are easier and less costly to install. They also have lower maintenance costs. Recirculating types are used where there is continuous foot traffic, such as in a store or supermarket entrance. Although there are different designs, the recirculating air curtain might be built into an entrance, and discharge air from a grille on one side of the entryway, then collect it through a receiving grille on the other side and return it through ductwork to the discharge grille. The air stream in this type of air curtain should ideally be low velocity and unobtrusive.
Non-recirculating air curtains are mounted horizontally above a door or vertically on the sides of the door, depending on the shape and size of the opening. A horizontal mounting is usually preferred, as it minimizes the chances that the air curtain can be damaged.
Selecting the Right Air Curtain for Your Needs
When choosing an air curtain, consider the following factors:
- Door Dimensions: Ensure the air curtain matches the width and height of the entrance for effective coverage.
- Mountain Options: Depending on the space and design, air curtains can be mounted horizontally above the door or vertically alongside it.
- Airflow Velocity: Select a model with appropriate airflow speed to counteract external wind pressures and effectively maintain the barrier.
- Heating Options: Some air curtains come with heating elements to provide warm air during colder months.
- Control Features: Advanced models offer programmable settings, remote controls, and integration with building management systems for optimized performance.