Do portable AC units work? Pros and cons

Key points

• Portable AC units act like small-scale air conditioners for individual rooms.

• Portable air conditioners are less effective and energy-efficient than other AC systems.

• Portable AC units are best for small spaces where you can’t use other air conditioning appliances.

Portable air conditioners can work well when you need to cool individual rooms without using a more effective air conditioning system, such as a window unit from one of the best air conditioning brands or an evaporative cooler. Portable air conditioners must be vented out a window and plugged into an outlet. 

You can use portable AC units from space to space, but they’re still quite heavy, so don’t count on being able to move them as easily as you could a fan. They’re not the quietest or most efficient way to cool down a space, but they’re good enough when you can’t install a window unit (for instance, if you live in an apartment building and the only window in your bedroom leads to a fire escape).

Here are the pros and cons of these portable air conditioners, plus some expert advice from Allen Rathey, director of the Indoor Health Council.

When should you use a portable air conditioner?

Portable air conditioners are best for cooling individual rooms that can’t be cooled by central air conditioning, window units or a ductless mini-split. Portable air conditioners aren’t as powerful as their window-mounted cousins, but they can do the job if you cannot have a window unit.

“Portables are also great for temporary living areas [and] rental properties,” Rathey said. “They can [also] augment the central HVAC in areas that may create a lot of heat, such as a home office with many computers, kitchens while baking and home gyms.”

As the name implies, these air conditioners are portable — but not as much as you may think. Portable air conditioners require a hose or two to vent out to the window, and at 50 to 80 pounds each, these units are heavy, too. So, while you can certainly move these units as needed, don’t plan on it being a quick or sweat-free job.

How do portable air conditioners work?

Portable air conditioners cool a space by pulling in warm air, lowering its temperature and venting the leftover hot air back outside.

Portable AC units pull in either surrounding indoor air or air from outside with a single or dual hose. Once the air is inside the machine, the filter, compressor, refrigerant and condenser coils all work together to cool down the stagnant air and remove its humidity.

In some machines, the excess moisture from this process ends up in a reservoir, which you will need to occasionally empty. Finally, the cool air gets expelled back into the room, while the leftover warm air gets sent outside via the machine’s window hose.

While these air conditioners are fairly easy to install, they require regular maintenance. You’ll need to check a portable air conditioner’s filter (and change it, if needed) monthly to keep it running smoothly and efficiently. Additionally, you’ll need to empty drip pans, reservoirs and drip hoses. Your portable AC’s manufacturer’s instructions will note other parts that need to be regularly maintained or replaced.

Single-hose

Single-hose portable air conditioners have just one hose connected to their main units. The hose runs from the unit to a window-mounted frame, where it expels leftover warm air from the cooling process. Single-hose units are cheaper — both in upfront and operating costs — than dual-hose units.

Dual-hose

Dual-hose portable air conditioners use two hoses to bring in warm air and push out leftover air. One hose will bring air from outside to the unit, while the other, like in a single-hose unit, will vent out excess hot air. Dual-hose units often use more energy than single-hose units but can cool a room faster.

How do portable ACs differ from other ACs?

There are a variety of cooling systems out there, and not all of them are good for every space. While portable air conditioners are best for individual rooms, other air conditioning units are best at cooling entire houses or multiple rooms. Here are a few other differences to keep in mind.

Central AC

Central air conditioning is the most common way to cool down a large space. A large outdoor unit cools down the air and sends the cold air to each room in your home via a system of ducts. Some central units also use a small indoor unit to help with the cooling.

Central air conditioning is far more powerful than a portable air conditioner, and newer systems typically use energy more efficiently than portable units. A central air conditioner is also much more expensive than a portable air conditioner, and it can’t individually cool down certain rooms.

Ductless mini-split

Ductless mini-splits cool down a space by using an AC unit in each room that’s connected to an outdoor compressor. Unlike central air conditioning, they don’t need ducts — hence the name. 

While both portable air conditioners and ductless mini-splits can be used to cool down individual spaces at different temperatures or times, ductless mini-splits are much more powerful. They can easily be connected to a heat pump, allowing them to provide heat in the cooler months.

However, ductless mini-splits are much more expensive than portable units, and their installation is much more involved — each unit needs a refrigerant line run to the outdoor compressor.

Window unit

Window air conditioners are cheaper than portable ones and are considered more effective, too. This is because window ACs can use outdoor air to cool down their coils, while portable ACs must use the inside air to do the same, creating negative pressure and inadvertently heating up the exact space it’s trying to cool.

However, window units are trickier to install than portable air conditioners, as they’re heavier and require the use of mounting hardware. Because of their weight and overhang, some apartment buildings have banned the use of window air conditioners.

A portable unit might also be a better — or your only — option if your windows are too small or don’t open correctly for a window unit. You also can’t install a window AC in a window that leads to a fire escape for safety reasons.

Heat pump

Heat pumps can both warm and cool a space. Heat pumps transfer heat from either the ground or the air and then send it into your home. While some portable air conditioners can also act as heaters, heat pumps can serve larger spaces with much less energy, as they transfer heat rather than create it.

Evaporative cooler

Evaporative air coolers cool down hot, dry air by adding moisture. Like portable air conditioners, they can be moved from space to space and are easy to set up. They use little energy, and they’re quieter than portable units. However, evaporative coolers shouldn’t be used in humid climates — adding more moisture to the air will only make your home feel more muggy.

How efficient are portable air conditioners?

Portable air conditioners range in how much energy they use to keep a space cool, but they’re typically less efficient than window units or ductless mini-splits. You can determine how efficient a portable air conditioner will be by looking for its combined energy efficiency ratio, or CEER.

CEER ratings are regulated by the Department of Energy (DOE), and they measure how much electricity an appliance uses to cool down a space. In 2020, DOE further updated its energy rating standards for air conditioners to improve energy conservation.

Rathey said that the higher the rating, the more efficient the appliance. Most portable air conditioners have CEER ratings of seven to nine, while many window units and ductless mini-splits will have CEER ratings between 10 and upwards of 20.

“Portables do lose some efficiency from the exhaust hose connecting the unit to an outside window, which releases some heat back to the room,” Rathey added.

How to maximize efficiency

To ensure you’re getting the most cooling power out of your portable air conditioner, make sure you remember these three things:

When should you upgrade to central air conditioning?

Portable AC units are worth it if you only need a single unit and have a small space to cool. This type of AC is far less efficient and effective than central air conditioning, so using more than one or two for an extended period will increase your energy bill and the inside temperature.

What’s next?

If you think your space needs a portable air conditioner, research reliable air conditioner brands to find a unit that will work for you. If you think your space is too big or your energy needs are too high for a portable unit to be worth it, you should determine what size air conditioner you need before making any decisions.

If you decide that portable air conditioners aren’t working for your space, you can get started with our picks for HVAC brands.