Let me start this portable air conditioner buying guide with some brutal honesty, because that’s kind of my whole thing: You probably shouldn’t buy one.

There, I said it. Portable ACs are the minivans of the cooling world: practical, a little awkward, and not what anyone dreams about. They’re significantly less efficient than window units, and they cost more to run. If a window air conditioner fits your space, get that instead. Your electric bill will thank you. We recommend the Frigidaire FHWW145WE1.

Still here? Good. Because there are plenty of legitimate reasons to buy a portable AC: weird windows, rentals with strict rules, rooms you can’t permanently modify, or the simple need to roll cooling from one room to another. If that’s you, this guide will help you buy the right one the first time, so you’re not selling a regret-purchase on Facebook Marketplace come September.

I’ve spent the last eight years testing dozens of these things. Same test room, same readings every 15 minutes for two-plus hours, same electricity measurements. So let’s get into what actually matters.

How Many BTUs Do You Actually Need?

BTU stands for British Thermal Unit, and the technical definition involves raising the temperature of water by a degree. You don’t need to memorize that. Here’s what you need:

Take your room’s square footage and multiply it by 20.

That’s it. A 500-square-foot room needs roughly a 10,000 BTU unit. Go too small, and your AC runs constantly while you sit there sweating and resenting it. Go too big, and you’ve overpaid for capacity you’ll never use and end up clammy to boot.

One catch: Portable ACs list two BTU numbers. Ignore the big flashy lab-setting number: It’s basically marketing. Look for the Department of Energy SACC rating (Seasonally Adjusted Cooling Capacity). That’s the honest one, and it’s the number that matters for real-world cooling.

Single Hose vs. Dual Hose

This is the difference between “fine” and “actually efficient.”

A single-hose unit blows exhaust outside, which creates a slight vacuum in your room. Nature abhors a vacuum, so hot air from outside sneaks back in to fill it. You’re cooling the room while inviting heat back in. Counterproductive, right?

A dual-hose unit uses one hose for exhaust and a second to equalize pressure, so you don’t get the “hot air sneaking in” problem. Dual-hose models are more efficient and a smarter pick for larger rooms. Single-hose units are cheaper and perfectly fine for a small bedroom, just know the trade-off you’re making.

Is Inverter Technology Worth It?

Short answer: yes.

Older AC compressors work like a light switch: fully on or fully off. The problem is that firing the motor back up from a dead stop requires a large current draw. Inverter compressors ramp the motor up and down to maintain a steady temperature, so they sip power rather than chugging it. They run quieter and cost less to operate. If a unit has an inverter, that’s a genuine point in its favor, not just a spec-sheet buzzword.

Do You Have to Empty the Water Tank?

This question comes up constantly, and the good news is: usually not.

Portable ACs dehumidify as they cool, which produces water. Most decent units evaporate that water and send it right out the exhaust, so there’s no tank to babysit. Some models need occasional draining or come with a hose for continuous drainage, but the majority I’ve tested are self-evaporating. Translation: one less chore.

A Word on “Portable”

They have wheels, and they roll between rooms beautifully, which is far easier than wrestling a window unit out of its frame. But “portable” has limits. These things weigh 60 to 80 pounds, so moving one up or down a flight of stairs is a legitimate workout. I’ve done it many times, and I always end up sweaty and gross.

You Still Have to Vent It

No getting around this one. Every portable AC needs to send its exhaust outside. Usually, that means a window and the included window slider kit. It doesn’t technically have to be a window: Any opening to the outdoors works, but if your room has no windows and you’re considering sawing a hole in the wall, that’s between you and your God (or landlord).

My Top 6 Portable Air Conditioner Picks

After running dozens of units through the same gauntlet, these are the six I’d actually spend my own money on.

Best Overall: LG LP1419IVSM (~$700)

A smart inverter unit with one of the lowest power draws I measured and among the best cooling in my tests. It offers app control and built-in storage for the cord and window slider. Pricey up front, but the efficiency helps earn it back over time.

Best Budget: Frigidaire FHPC102AB10 (~$340)

The quietest of all the top performers I tested on its high setting (55 dB, about the volume of normal conversation). It’s easy to install, cools about average, and its window slider fits an unusually wide range of windows.

Best with Heat: Friedrich ZHV16DA

An inverter unit that both heats and cools, so it earns its keep year-round. It tied for the best cooling in my tests, runs quietly, and took me about 15 minutes to install. It’s the one currently living in my bedroom.

Best for Large Rooms: Whynter ARC-14 (~$500)

A dual-hose workhorse and the subject of our most-viewed video ever. It’s louder than most portable ACs I’ve tested, but it cools big rooms like nothing else. Dual hoses are a must at this size, and this one delivers.

Best Battery-Powered / Off-Grid: EcoFlow Wave 3 (~$1,500)

Runs about 5 hours on a charge and works anywhere: tent, car, van, RV, or campsite. It’s a specialty pick, not your primary room AC, and you’ll need to rig your own window venting. But for off-grid cooling, nothing else comes close. Check out our full review.

Honorable Mention: Midea MAP12S1TBL (~$560)

Dual-hose, inverter, and impressively quiet (43.2 dB on low). It cooled my bedroom well for a couple of summers before I upgraded to the Friedrich. Still a solid, reliable choice.

The Bottom Line

A great portable air conditioner is quiet, properly sized for your room, dual-hose if your space is large, and ideally runs an inverter compressor. Get those things right, and you’ll stay cool all summer without buyer’s remorse.

For the full breakdown, including real test data, cooling numbers, and noise measurements for every pick above, watch my complete video review of the six best portable air conditioners:

Stay cool out there.