How Do Portable Air Conditioners Work and Do You Need One?

Portable ACs help you keep your cool

Close-up of a portable AC
Photo: onurdongel / iStock / Getty Images Plus / Getty Images
Close-up of a portable AC
Photo: onurdongel / iStock / Getty Images Plus / Getty Images
Highlights
  • Portable AC units offer a flexible way to cool a room in your house, but they need to vent their exhaust in order to function properly.

  • Most, but not all, portable AC units are vented through a window.

  • Dual-hose portable AC units work better than single-hose units, but they’re more expensive.

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Imagine you found your dream home, but it’s not set up for central AC. You’re not ready to commit to installing your own ductwork for a fully fledged HVAC system, and you don’t exactly love the idea of a window AC unit. Enter the portable air conditioner, which can cool just about any area that has the floor space for it (and a space to vent the unit, usually out a window). It may not be the most elegant solution, but it’s one of the most flexible. Learn how portable air conditioners work to see if they may be the solution to your AC woes. 

How Do Portable Air Conditioners Work?

Dual-hose versus single-hose portable ACs illustrated, with dual-hose having air brought in to cool the condenser coil

Like other types of air conditioners, including central air and window units, portable air conditioners use refrigerant to cool the air they pull in and circulate. Hot, stagnant air travels into the unit through its intake filter by a motor and is brought into contact with the refrigerant in the evaporator coil. From there, the air travels to the compressor, where heat transfer occurs (i.e., your hot air becomes cool air). That cool air is then vented back out into the room, while the heat is vented out as exhaust through a window. 

Some portable air conditioners also dehumidify the air while cooling it. If you get a dehumidifying unit, you may have to drain your portable AC every so often (and you’ll have to do it more frequently if you live in a particularly humid location). Depending on the type of unit you have, the water might drain alongside the hot air through the same exhaust channel, which means less maintenance for you.

Types of Portable Air Conditioners

Although they largely work using the same physics, there are a couple main types of portable air conditioning units to consider.

Single-Hose

Single-hose portable air conditioners, as their name suggests, have a single hose through which their exhaust is vented. Warm air and moisture travel away from the unit through this hose, which most people vent out a window. Single-hose portable air conditioners tend to be more affordable than dual-hose units, and they may also use less energy. However, they’re also less efficient than their dual-hose counterparts.

Dual-Hose

Dual-hose portable air conditioners have, you guessed it, two hoses: one to vent exhaust and one to pull in fresh air from outside, which can increase the circulation of fresh air in the space you’re cooling. These may provide faster and more even cooling, but they tend to cost more to purchase and operate.

How to Maintain Your Portable Air Conditioner

Fortunately, portable air conditioners are fairly easy to maintain. Along with draining the unit as described in its instruction manual, you’ll also need to clean the air filter regularly to ensure the unit continues to operate as efficiently as possible. (For heavy use, you may need to clean the air filter as often as once every two weeks.)

Additionally, wipe down the external grille of the unit periodically to keep it free of pet hair and other household debris that you don’t want in the air. If you plan to pack up and store your portable AC unit during the cooler months, keep it in a cool, dry area—ideally under a tarp or back in its original packaging.

Is a Portable Air Conditioner Worth It?

A man checking the air flow of a portable AC
Photo: M-Production / iStock / Getty Images Plus / Getty Images

We’ll be real with you: A portable air conditioner simply isn’t as efficient or effective as other climate control methods like central AC. Although they don’t block out your entire window, they still take up valuable floor space and aren’t always the nicest to look at. That said, in some homes and situations, they’re the best solution for a flexible way to keep your home at a livable temperature. This is particularly true if you don’t often need air conditioning or don’t have the budget for a brand-new HVAC system at the moment. 

Have more questions? Your local AC installer can help assess your needs and find the right solution for your home and lifestyle.

Frequently Asked Questions

Not necessarily. Some portable air conditioners may be vented out a door, wall, or ceiling—or even into another room. It’s not necessarily dangerous to run a portable air conditioner without venting it, but it is counterproductive since the unit needs to vent the heat in order to cool the room down in the first place. Without venting your portable AC unit, you’re essentially running a dehumidifier and increasing the temperature in the room. 

Not if you have a standard unit. Because portable AC units actually work to dehumidify the room, you’ll likely need to drain the unit from time to time—but you won’t have to put water into it. There is, however, another type of air conditioner called a swamp cooler that requires water to operate. If you have a swamp cooler, you may need to fill a reservoir with water and potentially ice. But a swamp cooler is different from a standard portable AC unit.

While all portable AC units will collect moisture as part of their cooling and dehumidifying process, whether and how often you need to drain them depends on what kind of unit you have and the natural humidity levels where you live. For example, if you live in a very dry area and have a self-evaporating unit, you may not need to drain your portable AC very often at all. Some units may automatically drain collected moisture out the window through their exhaust vent.

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