The Kitchen Challenge – How Negative Pressure can lead to negative reviews

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  • October 06, 2022
  • by Powered Aire

One of the most common questions we get is “my commercial kitchen has a fly problem. Will an air curtain solve this issue?”. While we’d love to say “of course, we’ll get you set right up”, the answer is not always that simple.

If you own a restaurant, you know all too well that you can serve 100 customers and 99 of them will leave happy, full, and content to return. BUT…there’s that one person who will have a fly land on their table and before you know it, they’ve written a negative review and made it sound like a plague of locusts descended upon their meal.

Warranted or not, a negative review is a killer. So, what can be done to decrease the potential for these flying pests ruining a meal? Of course…put up an air curtain! While we wish it was that easy, there are a few things to consider first.

ATOP THAT LIST IS NEGATIVE PRESSURE. Restaurant kitchens are hot. With ovens, grills, deep fryers, and heat lamps in near constant use, it’s understandable. To manage that heat, you need exhaust fans. A typical restaurant kitchen has exhaust hoods with considerably higher levels of power than what you’ll find in a residential kitchen. Depending on the characteristics of the kitchen, the exhaust can create a vacuum. If you’ve ever opened a door and felt like ghost was holding it closed despite your best efforts, you’ve experienced negative pressure.

And with most commercial kitchens, there is a back door with a steady stream of deliveries coming in and trash going out. Each time the door opens, the negative pressure pulls in all sorts of unwanted elements. Couple the wonderful aromas of the kitchen and the not so wonderful aromas of the nearby trash bin and you are going to get flies. Lots and lots of flies.

The area outside of a kitchen can be a magnet for flies
The area outside of a kitchen
can be a magnet for flies

Air curtains are ideal solutions for preventing the infiltration of flying insects but when a kitchen has excessive negative pressure, they simply can’t overcome the pressure.

So how do you keep flies from entering through your restaurant back door? You’ll first need to address the negative pressure. An HVAC professional can recommend and install an air Make-Up kit that will help balance the pressure inside the kitchen. If the Make-Up kit provides proper balance, you’ll notice that doors open easier and will have taken a key first step into addressing your fly problems.

NOW IT’S TIME FOR THAT AIR CURTAIN: As long as the enticing smells from the kitchen (along with the not-so-wonderful) smells from the trash continue, so will the flies. This is where an air curtain will prove an ideal solution. Also known as an air door, these devices create a barrier the blocks the unwanted outdoor elements (flies, odors, exhaust) but allows unrestricted access to break areas, trash cans and freezers. While it’s recommended that most air curtains be mounted on the interior side of a door, for insect control applications, we recommend mounting on the exterior side (outside). The benefit of an outside mount air curtain is that when the airflow hits the ground and splits, 80 percent of that flow will go outside. This makes it harder for insects to pass through.

Air Curtains on restaurant back doors can provide excellent bug, exhaust and temperature control
Air Curtains on restaurant back doors can provide
excellent bug, exhaust and temperature control

KEEP IT CLEAN: And speaking of the outside, it’s important to make every effort to keep the area as clean as possible. Move the dumpster as far away as conveniently possible. Keep lids on items. Eliminate standing water (flies and mosquitoes love water). Ensuring a tidy environment will go a long way in reducing the number of flies.

BUG LIGHTS WORK WELL: As we mentioned, you can prevent 9 out of 10 flies from entering but it’s that one fly that will earn a complaint from a customer. In most cases, flies enter through the back, but they’re attracted to the light and will eventually make their way to the front where there is ample lighting and bright windows. Fly lamps are effective tools that attract the bugs and trap or kill them before they find their way to a customer’s plate. The one-two punch of an air curtain and a bug light can be extremely effective against flying pests.


  1. Address the negative pressure - You can’ turn off the exhaust fans but you can create a balanced environment. If there is negative pressure in your building, it will always need to be addressed before any effective means of insect control can be implemented.
  2. Add an Air Curtain – Once the pressure is balanced, an Air Curtain can work its magic by creating an invisible barrier to keep out the flies and other pesky problems.
  3. Be Clean - Maintain a clean area around the outside of the door. If possible, move the dumpster farther away, ensure trash cans are covered and that the outside space near the door is as clean as can be. Eliminate water around door openings. Ground water, buckets.
  4. Consider Bug Lights/Insect Traps – Additional insect tools provide secondary means of control. A bug light will attract flies (and catch them), preventing them from making their way to the front door.


Just in case your wheels are still spinning, here are a few more things to consider. There are several standards and codes surrounding restaurants and food preparation areas. Some states, like Alabama, California, and Texas, even have laws that require methods of fly control.

The USDA and FDA list air curtains (6-202.15) as a means of insect control if/when the windows or doors of a food establishment are kept open for ventilation.

The excerpt reads:

Except as specified in (B) and (D) of this section, if the windows or doors of a food establishment, or of a larger structure within which a food establishment is located, are kept open for ventilation or other purposes or a temporary food establishment is not provided with windows and doors as specified under (A) of this section, the openings shall be protected against the entry of insects and rodents by:

  1. 16 mesh to 25.4mm (16 mesh to 1 inch) screens;
  2. Properly designed and installed air curtains; or
  3. Other effective means.

Want to discuss your kitchen challenges? Contact a Powered Aire representative today or learn more about our complete line of Restaurant Air Curtains Here.

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