How Many Windows Open for Swamp Cooler?

Evaporative or swamp coolers can be as efficient in cooling your home as traditional air conditioners.  But they work slightly differently – you need to provide some airflow.

That’s why this guide will be all about how many windows open for the swamp cooler you need for efficient cooling. There needs to be more clarity about how many windows you need to keep open and whether you can open a door instead of a window.

Let’s dive into the details.

Why Should You Open Window When Using a Swamp Cooler?

If you’re using a swamp cooler to cool your room, they pull air through a cooling unit with a porous surface. This surface allows air to flow so that a fan inside the cooler pulls in enough air.

This air circulation is crucial for the swamp cooler to work correctly. A significant difference between regular air conditioners and swamp coolers is airflow. That’s why they need a stream of fresh air continuously to cool their home effectively.

By keeping the windows open, you’re providing your swamp cooler the air it needs to cool your home down in high heat. It also releases the pressure built up as your cooler introduces cold air into the room.

The fresh air gets pulled inside the cooler pads and pushes the cool air back into the home. It is what lowers the temperature.

Without an open window or air circulation, your cooler will recirculate humid air into the atmosphere. Although that can feel cool, it’ll be clammy.

The video below does a fantastic job explaining it and where swamp or evaporative coolers work best.

With that being said, there are times when you might want to keep some windows closed.

Specifically, if you’re trying to cool a particular room, close other areas’ windows. It will allow the cooler to cool that spot faster.

How Many Windows Open for Swamp Cooler?

Alright, so having the windows open is essential for a swamp cooler. But how many windows do you need to open? Before we get into the technical details, let’s clear out one thing.

How many windows you need to keep open depends on the size of your windows and how powerful your swamp cooler is in the first place.

Thankfully, there’s a recommended standard, and you can adjust the standard according to your window size and swamp cooler strength. Normally, you should have 1 to 2 sq ft of air flow for every 1,000 CFM.

Since swamp coolers can vary in airflow, you need to understand how we landed on this number. All the calculations are based on a recommended range of air changes per hour.

Opening too many windows is a bad thing too. You should experiment a bit as well.

How Much Should a Window Be Open for a Swamp Cooler?

Balancing air getting in and getting out is essential. That’s why you don’t want to open the windows too wide.

Otherwise, that can have the opposite impact and let in too much hot air.

Just partially opening the windows should be just fine. It will allow just the right amount of warm air to escape and replace it with cool air by your swamp cooler.

Can I Open a Door Instead When Using Evaporative Cooler?

Yes, you can! Opening your door instead of a window will work just as well. The main idea here is to allow for enough airflow and circulation. Your swamp cooler needs a constant flow of fresh air to work.

As long as you’re giving it that, it should be fine. Whether you open your windows or doors doesn’t matter all that much.

However, some people might not prefer keeping the doors open to their rooms. You certainly don’t want to keep the entrance door for obvious security reasons.

But if you’re in your room and want to have the door partially open instead of your windows, that’s fine.

Another thing you should keep in mind is how wide you open your doors. They’re larger than windows.

Don’t open it so much that you let the cool air escape as well. By the way, this video provides you with tips for making your swamp cooler more effective (you can also check our article about making evaporative coolers colder).

Will Evaporative Cooler Work if I Cannot Open Any Window?

Evaporative coolers will work if you don’t open the window. The area will still feel cool. But since there’s no fresh air and proper circulation, your cooler will recirculate the humid air back in.

Although this will still drop the temperature, it feels uncomfortable and clammy. If you’ve ever lived in a humid place, you’d know the exact feeling. That’s why evaporative coolers need to have open windows for air circulation.


To wrap up, you should partially open a window to allow your swamp cooler to cool efficiently.

As far as how many windows open for a swamp cooler works best depends on the size of the windows and the strength of your cooler.

The standard is for every 1,000 CFM, you should have at least 1 to 2 sq ft of airflow.

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