How Do Ventless Portable Air Conditioners Work and Are They Right for Your Home?

Updated June 29, 2022
Portable air conditioner
Photo: AlexLMX/ iStock / Getty Images Plus / Getty Images


  • Ventless portable air conditioners evaporate water to cool the air

  • They’re easy to install and low maintenance—especially compared to traditional units

  • A ventless AC unit costs $110 to $420 on average

  • These units work best in warm and dry climates

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Don’t let the name fool you: A ventless portable air conditioner isn’t actually an air conditioner—but when you’re enjoying the cool, refreshing air these little machines provide, you probably won’t care much about what they’re called. All you may be thinking about is how to get one for every room!

Keep reading to understand these systems' main benefits and drawbacks to find if it’s right for your home.

What Is a Ventless Portable AC?

A ventless portable air conditioner is a system that evaporates water to cool the air. These systems require only water and access to power to work. 

The name includes the term “air conditioner,” ventless portable air conditioners are not in fact air conditioners—at least not in the traditional sense. Standard ACs pull hot air into the system to cool, filter, and dehumidify it before recirculating it back into the room. But ventless ACs don’t have a unit that connects outside the home to pull heat in, so they don’t function as a traditional air conditioner unit. 

To avoid confusion, many experts refer to them by other names such as:

Whatever you choose to call them, the fact is ventless portable ACs are affordable, energy-efficient, and keep your space cool if the climate is right.

How Do Ventless Air Conditioners Work? 

Have you ever noticed how much cooler it feels sitting beside a body of water in the summer? This is because water draws and retains more heat than pretty much any other substance on Earth.

Ventless air conditioners model the same principle. The unit contains its own little pond (usually between 14 and 42 pints of water) that evaporates tiny water droplets into the room, which cool the air after transforming into a gaseous state.

Here’s how ventless ACs operate: 

  • An open tank at the bottom of the unit holds the water reservoir. This gives it a low center of gravity, which helps prevent tipping. 

  • A fan and pump draw water from the reservoir onto a cooling pad, pulling room air across the pad to load it with moisture. 

  • The moistened air is cooler and feels more refreshing than the dry, hot air in your room. 

In fact, an evaporative cooler can quickly lower the room temperature by as much as 30 degrees.

Swamp coolers continue running this cycle until the humidity level is too high to evaporate water. Because of this, they’re best for dry climates.

Benefits of a Ventless AC Unit 

Ease of Portability 

Truly ventless and portable, you can place these units anywhere with access to an electrical outlet.

Easy Installation

Simply plug in, add water and go—with one caveat. Only plug the machine directly into your outlet, as extension cords can cause a short, throw a breaker, or overheat and become a fire hazard.


A ventless AC unit is more affordable than other options, usually priced between $110 to $420. Window units cost $170 to $980, depending on the size of the system and its capacity. A traditional HVAC system will run you between $5,000 and $12,500. 

Low Maintenance

Evaporative coolers don’t require installation or maintenance, meaning you won’t need to call or pay a professional. Plus, unlike window units or traditional HVAC systems, you eliminate any need to troubleshoot or repair the system. 

More Sustainable

Ventless systems are a sustainable solution compared to other options. Evaporative coolers emit no harmful gases, use no refrigerant, and leave a smaller carbon footprint than a central HVAC unit.

Energy Efficient

If keeping your home cool, your energy costs low, and your carbon footprint even lower is a priority, go with an evaporative cooler. Most ventless portable air conditioners that run continually consume between 90 and 160 watts per hour. By comparison, window units consume around 500 watts per hour, and central air conditioning systems suck up around 3,500 watts per hour. 

In fact, you can run a ventless unit 24 hours a day for a fraction of the cost of running a central air conditioner. 

Drawbacks of a Ventless AC Unit 

Not For Humid Climates

Evaporative coolers don’t function similarly in every climate. If you live in a humid environment, swamp coolers probably won’t work for you (despite the “swamp” title implying otherwise). Simply put, the air is already wet and can’t absorb much more water. They’re best for dryer areas where the air's moisture is low.

Lower Output

While efficient, ventless AC systems don’t have as much output as other systems. They’re best for cooling one room or a small space—not an entire home. 

Slow to Cool

If not running continuously, ventless AC units can take quite a while to cool a space. You’ll want to ensure you keep the water tanks full to work properly all day long.

Is a Ventless Portable Air Conditioner Right for You?

Ventless portable air conditioners are best for:

  • Warm and dry climates: If you live in a warm, dry climate, then you should consider giving an evaporative cooler a try. 

  • Single-room use: Most models will only cool a single room, and you’ll want to make sure to keep your doors and windows closed for optimal cooling. 

  • Budget-conscious homeowners: The affordability and ease-of-use mean you may be able to afford to install an evaporative cooler in almost every room for less than a traditional system.

Additional Questions About Ventless Portable AC’s

Do portable ventless air conditioners work?

Yes, but they don’t feel the same as an AC-cooled room. You’ll feel cool, moist air, opposite from an HVAC system that dries the air as it cools.

Are ventless AC units good?

If you’re looking for a portable, budget-friendly cooling solution that doesn’t require any venting or installation, a ventless AC system is a good option. 

Is there a portable air conditioner without venting?

Evaporative coolers offer a portable air conditioning solution without the need for venting. There is no hose required with these systems.

Do all portable air conditioners have to be vented out a window?

No. With a ventless portable AC system, you don’t need to vent anything out the window—but it will be harder to circulate the hot air from the room without one, so you’ll need to come up with another solution (like a fan).

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