Protect Yourself From Summer Heat With the Best Portable Air Conditioners

No one will ever tell you that a portable air conditioner is the most elegant way to cool a home. They can be loud and clunky, with unsightly exhaust hoses. They’re less efficient than window units. But they are a solution to several common problems: Portable A/C units are great for rentals with no central air or windows that fit a traditional A/C unit. You can buy and install one quickly. They can help cool areas without HVAC ducts. They can even serve as supplemental A/C for a room that gets hotter than the rest of the house.

To help you avoid all that, we spoke to two HVAC installation and repair experts, delved deep into the many numbers and features manufacturers advertise, and researched which models have a reputation for doing the job. This guide should help you choose the best portable air conditioner for your needs.

• Best for Large Rooms: Whynter ARC-1230WN 
• Best for Small Rooms: DREO Smart Air Conditioner 515S
• Quietest: LG Dual Inverter With Wi-Fi
• Best With Heater: Midea DUO With Heat Pump
• Best Budget: SereneLife Portable Air Conditioner

While we didn’t test these portable air conditioners in our own homes, we did a lot of research to understand the many products on the market and come up with the best options available. We looked at competitor research, data on the best sellers, efficiency ratings, and customer reviews. We also made sure to include options for a variety of room sizes, budgets, and priorities.

To make this guide, we spoke to two HVAC experts with decades of experience installing and repairing air conditioners to find out what to look for in a portable air conditioner and how to make this big purchasing decision:

• Kevin Bohnet, HVAC program director at Fortis College in Salt Lake City, Utah
• Joe Haycock, president at Fresh Air Concepts,, a residential and commercial HVAC company in Linthicum Heights, Maryland
  

An air conditioner’s BTU (British Thermal Unit) indicates its cooling power. The bigger the room, the higher the number of BTUs per hour you’ll need. These days, when you shop for a portable air conditioner, you’ll see more than one BTU, along with some other useful numbers:

ASHRAE BTU vs. SACC BTU: Up until 2020, manufacturers listed air conditioner BTU as measured by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). The problem is that ASHRAE tests BTU in laboratory conditions. “Most of the time, what you end up having with these portable air conditioners is somebody’s got it in a space that’s super hot — it’s 95 degrees F in there, they’ve got some kind of a long exhaust run trying to get the heat out a window or some kind of other vent somewhere, and the capacities that were printed on the box, they don’t actually get it. It says it can cool 400 square feet, they have 400 square feet, and it’s not cooling,” explains Joe Haycock, president at Fresh Air Concepts, a residential and commercial HVAC company in Linthicum Heights, Maryland.

The really confusing thing here is that brands still often use ASHRAE BTU ratings in their product names. That’s why we listed both numbers in the product descriptions.

• BTU: Find out the dimensions of the room you need to cool, and make sure to buy a machine with the BTU to match, using the SACC number or the manufacturer’s recommendation. A machine with a BTU rating that’s too low for the room size will have to run continuously to reach the temperature you want, Bohnet explained. One that’s too big can also be a problem. “If it’s oversize, it’s going to cool really quickly, and then shut off” because the thermostat will indicate it got to the right temperature even if it hasn’t evenly cooled the room. Then it will warm up quickly, too, causing the A/C to turn back on. Turning on and off frequently isn’t just annoying. “It puts wear and tear on the equipment, number one,” adds Bohnet, “and it’s just inefficient.”

• Efficiency: The CEER number is one of the best ways to estimate the running cost of a portable air conditioner. The efficiency of the A/C once it’s in your home will vary based on the room, how you set it up, ceiling height, and how insulated your home is. Remember that it may wind up costing more to buy a cheaper air conditioner that’s inefficient and runs up your electricity bill.

• Installation options: Though installing these units is easier than installing window A/Cs, you still need to place the exhaust hose in a window (or something similar), with a panel to seal the space around it. Most units come with an installation kit that fits vertical or horizontal window openings. Look closely at the kit and how you’ll need to secure it in place. You may need to customize it to seal unusually shaped openings and stay in place.

• Size and weight: While other types of air conditioners stay out of your way, portable units take up space in the room. You may also be moving it from room to room, or taking it in and out of storage. Make sure you can lift or roll yours easily.

• Draining: Cooling the air requires removing the heat and humidity from it, which results in water condensation inside the unit. Many new models are self-evaporating, so you don’t have to figure out where to let them drain out. Some models still require you to set up a drain hose or empty the water from it manually. Even self-evaporating models may require this after a very humid day.

• Sound: While in other types of air conditioners, the compressor sits on the other side of the window or completely outside, with portable units, it’s all there in the room with you.
  

Without going into too much detail about how air conditioners work, we’ll just explain that they don’t just pull air in and blow it out like a fan. They pull in additional air to cool the compressor and condenser and then blow the resulting hot air outside. That’s why all air conditioners have at least one exhaust hose. “The problem with the single hose is you’re drawing air wherever it can get the air, so you’re going to draw it from the rest of the house,” Bohnet says. That means you might be inadvertently cooling more than just your target room, which is inefficient.

A more recent innovation is the double hose, which draws in outside air to cool. “We’re not pulling unwanted air from other areas,” Bohnet says.

“You want to pull in the hottest air nearest the source, [cool] it, and then send it back out,” says Haycock. “Place it near exterior doors, windows, or any part of the home that gets the most heat. Depending on the region, certain sides of the home get hotter during the day.”

You also need to consider the placement of the window where you’ll attach your exhaust hose. While you can technically buy hose extensions to place the unit farther from the window than the length of the included hose, Haycock recommends checking the unit’s manual for limits regarding the length of the hose and how many bends it can withstand. “If there's too much resistance in the exhaust duct, the fan motor can fail, the unit can overheat, and that leads to early compressor failures,” he warns.

In addition to the placement guidance, Haycock says you can do a few other things to keep your portable air conditioner cooling efficiently.

Properly install your exhaust hose: Skipping this step means you’ll be simultaneously cooling and heating the room.

Clean air filters regularly: “[Dirty filters] are the number one killer of units,” Haycock says.

Check the water collection reservoir: The A/C will usually shut down if that gets too full, even in self-evaporating units.

Wait a day to use the unit if it’s been lying on its side: “There’s oil inside of that unit that keeps the compressor lubricated, so if you tilt it … most manufacturers recommend that you let the unit settle for at least 24 hours before operating it. That allows the oil to settle back down into the bottom of the compressor,” Haycock says.