Air Curtain Sizing Selector

What Is an Air Curtain, and What Do Air Curtains Do?

Quick answer: An air curtain, also called an air door, blows a downward stream of air across an open door. That moving air separates the conditioned air inside from the outdoor air outside, so it blocks drafts, dust, and flying insects and saves energy without anyone closing a door.

An air curtain is a fan unit mounted above a doorway. It pulls in room air and pushes it out as a fast, even stream of air aimed at the floor. That sheet of moving air forms an invisible barrier across the open door. On one side sits your conditioned air; on the other side sits the outdoor air. The air curtain keeps the two from mixing, which is exactly why it is also called an air door.

So what is an air curtain used for? Air curtain commercial use is most common at a store or office, where it holds heated or cooled air inside while the entrance door stays open for customers. At a kitchen or loading dock, it keeps flying insects, dust, and fumes out — and yes, do air curtains keep bugs out is one of the top questions, with the short answer being that a strong, well-aimed air stream stops most of them. At a cold storage room or walk in freezer, it slows the cold air from spilling out every time the door opens. In every case the goal is the same: seal the opening with air instead of a physical door.

Air Curtain Types at a Glance

Each type uses the same idea, a downward stream of air, but differs in velocity, build, and heat. Match the type to the door and the environment.

Air Curtain Terms You Will See

A quick glossary of the words used on spec sheets and in this tool.

Air Curtain Questions, Answered

Do air curtains save energy?

Quick answer: Yes. A properly sized air curtain cuts doorway air infiltration by roughly 60–80% and can avoid up to 70% of the heating and cooling loss at an open door, often paying for itself in one to two years on busy doors.

Air curtain energy savings come from sealing the opening. Every time a door opens, warm or cooled conditioned air escapes and outdoor air rushes in, which forces your HVAC to work harder. The stream of air closes that gap. Research on stores with heavy foot traffic has reported energy savings above 30% at the entrance, and an AMCA and TRC study found an air curtain cuts infiltration about 65%, far more than a vestibule at roughly 23%. The savings grow with door traffic, opening size, and how cold or hot it is outside.

How effective are air curtains, and are air curtains effective?

Quick answer: Very effective when sized and installed correctly. A correctly designed and installed air curtain blocks 60–80% of air infiltration and most flying insects. Effectiveness drops fast if the unit is too short, too weak for the door height, or mounted poorly.

Effectiveness is not automatic. The air curtain only works if the stream of air reaches the floor with enough speed to resist the pressure across the door. That means three things must be right: the unit is at least as long as the door is wide, the velocity matches the door height, and it is mounted level and close to the opening. Get those right and an air curtain rivals a vestibule while taking no floor space. Get them wrong and the barrier breaks, letting air and bugs through.

Do air curtains keep flies and bugs out? (ServSafe)

Quick answer: Yes. A correctly designed and installed air curtain keeps most flying insects out, and ServSafe food safety guidance lists an air curtain, also called an air door or fly fan, as an accepted way to keep flying insects away from an outside entrance.

The fast downward air makes it hard for flies and other flying insects to fly through the opening, so they turn away. This is why pest control air curtains and insect air curtains are common at restaurant, kitchen, and food-plant doors. The phrase you will see in food safety training is that a correctly designed and installed air curtain can be used to keep flying insects out. For it to count, the unit must cover the full door width, run whenever the door is open, and push air strongly enough to reach the floor.

What air curtain is best for a walk in freezer or cold storage?

Quick answer: Use an unheated, high-velocity cold storage air curtain built to resist condensation. Never heat a freezer unit. It should run only while the door is open and drive a strong stream of air to the floor to hold the cold air in.

Cold storage doors lose the most energy of any opening, because the temperature gap between the cold room and the space outside it is large. When you shop for an air curtain for cold storage, look for a cold storage air curtain that uses higher velocity than a retail unit and is built so moisture does not freeze on it. A cold air curtain like this stays ambient (unheated) — adding heat would fight the very cold you are trying to keep in. For a walk in freezer, pair the air curtain with strip curtains or an auto-closing door for the best seal.

How to clean an air curtain

Quick answer: Switch it off, wipe the intake and discharge grilles, clean or replace the filter, and vacuum dust from the fan and coil. Clean every one to three months, more often in food or dusty areas. A stainless steel unit wipes down with a food-safe cleaner.

Dust on the intake chokes airflow and weakens the barrier, so cleaning is part of keeping the unit effective. Turn off power first. Remove and wash or swap the filter, wipe both grilles, and vacuum the fan blades and any heating coil. In a kitchen or food plant, grease builds up faster, so a stainless steel air curtain that wipes clean is worth the cost. Check the manufacturer manual for the exact filter and any greasing the motor needs.

How to install an air curtain

Quick answer: Mount it level on the inside, directly above the door and as close to it as possible, sized to span the full width. Wire it to a door switch so it runs only when the door is open, then confirm the air reaches the floor.

Air curtain installation is straightforward but precise. The unit goes on the warm or conditioned side of the opening, centered and level so the stream of air is even across the door. For wide doors, butt two or more units together with no gap. Add a door-limit switch or magnetic contact so it powers on only while the door is open, which protects your energy savings. Heated and hot-water models need the right electrical or plumbing connections, so for those a licensed installer is the safe route. Always follow the manufacturer manual — for example, a Berner air curtain manual lists the exact mounting height and CFM for each model series, and if you are matching a specific unit such as an HCR-series model, check that spec sheet directly.

Air Curtain Selection by Application

A side-by-side guide to velocity, heat, and build for each common use.

General guidance. Confirm exact velocity (CFM and FPM at the floor) against the manufacturer's published data for your door height.

Three Different Things Called an "Air Curtain"

The phrase "air curtain" is used for three unrelated products. This tool and guide cover the first one. Here is how to tell them apart.

Frequently Asked Questions