Here’s Why Grocery Stores Always Blast You with Cold Air as You Walk In

While the blast of cool air is nice on sweaty summer days, this "air curtain" actually has an important job.

If you’ve ever walked into a grocery store on a scorching hot day, you’ve been grateful for that blast of frigid air when the doors open. There’s nothing like a burst of ice-cold air on a day that could melt the asphalt in the parking lot.

The grocery store is air-conditioned on its own, though, so what’s the deal with this entrance fan? You might think the icy blast is for customer comfort on hot days—but it’s not. It’s actually called an air door, or an air curtain, and it functions as a barrier to keep unwanted outside materials from getting inside the store.

Speaking of cool air, take note of these other common air conditioner myths.

What Is an Air Door?

Most air doors are large fans installed above an entrance or exit’s door frame. Essentially, the cold blast of air—though sometimes in can be warm, too—acts as a second door.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) says this air door is a broad stream of air circulated across the doorway of a conditioned space. The air stream moves at just the right angle to keep the air outside from coming in!

What Does It Do?

The blast of air might be a nice refresher before you shop for produce, but it has a purpose. The air doors aren’t designed for people—they’re designed to keep out unwanted pests and hot air.

It Keeps Bugs Out

Gnats, wasps, flies of all kinds and mosquitoes thrive during the warm weather months, and would absolutely love to make their way into a grocery store full of produce and people. The easiest way for them to get into the store is through the same entrance that we use. But while we’re able to easily walk through the wall of cold air, insects will be blown away. The air door also keeps dust and dirt from entering the building on wind currents.

Learn how to keep flies away from your patio with this simple DIY trick.

It Keeps the Store Temperature Low

Whenever I leave an air-conditioned space with the door open, or have the windows down in an air-conditioned car, I can hear my dad’s voice in my head asking, “Why are we cooling the outside?” Turns out, grocery stores don’t want to cool the outside, either. With so many people entering and exiting the building, an air door prevents the cool air inside the store from escaping, and keeps the hot air from coming in. See what other secrets your grocery store won’t tell you.

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Hannah Twietmeyer
Hannah is a writer and content creator based in Milwaukee, Wisconsin, with a passion for all things food, health, community and lifestyle. She is a journalism graduate from the University of Wisconsin-Madison, and a previous dining and drink contributor for Madison Magazine.