7 Best Air Conditioners For Windowless Rooms (2023 Reviews)

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While pretty much any windowless air conditioner can help you feel the cool air and give some airflow to your stuffy room, only the best windowless air conditioner can do it the right way.

If you're wondering how I know this, it's because I've spent quite a lot of time dealing with air conditioners and climate control, and I know how hard it is to get the right portable AC for your home.

Thankfully, you don't have to spend years navigating this space because I've prepared a great list of windowless air conditioners for you to pick from - regardless of how big or small a space you wish to cool down.

Editor’s Choice

HESSAIRE MC37M

Ease Of Use

4.4

Cooling Ability

4.2

Value For Money

4.2


Our Score

4.3

Best High-End

HESSAIRE MC61V

Ease Of Use

4.0

Cooling Ability

4.0

Value For Money

4.0


Our Score

4.0

Best For Garages, Gyms, & Workshops

Portacool Jetstream 230

Ease Of Use

4.5

Cooling Ability

4.5

Value For Money

4.1


Our Score

4.4

7 Best Windowless Air Conditioners For Low Air Flow

1. HESSAIRE MC37M (Editor’s Choice / Best Overall / Best Value)

Ease Of Use

4.4

Cooling Ability

4.2

Value For Money

4.2


Overall Rating

4.3

CFM Airflow

3100

Room Size (Cooling Area)

Up to 800 sq ft

Water Tank Capacity

10.3 gal

Runtime

Up to 4 hours

Power Consumption

250 W

Noise Level

Up to 60 dB

Warranty

1 year

It’s not often you see a large yet still stuffy space, but if you have that problem - Hessaire MC37M is the best windowless air conditioner you can buy today.

This portable AC can easily cool down any open-concept apartment up to 800 sq ft (or possibly even larger if the conditions are right), and let me tell you, for around $350 - I don’t know many others that do.

With a super mighty oscillating 3100 CFM fan, I can confidently say that you’ll definitely feel the breeze when this one’s up and running.

In fact, if you set this one to High (from three available speeds), you’ll be cold standing in front of it - which is a good thing!

Two things that became obvious when I was testing this one are that it's very energy-efficient and can drop the temps up to 30 degrees.

That kind of cooling power paired with top-of-the-line energy consumption is not something you often see in a portable air conditioner this beefy.

At most, I saw a power consumption of up to 250W an hour, which is up to 10 times less compared to a standard AC for the same level of temperature drop.

You’ll see later on that I added a mini-split, Pioneer WYS012A-20, to this list - and this one both uses less power and cools a greater area for a fraction of the cost.

If that doesn’t make this the best portable air conditioner at this price tag - I don’t know what will.

Also, this one doesn’t give you the option to choose between cooling and fan-only, which I honestly appreciate since it makes using it quite effortless.

While it's not the prettiest windowless air conditioner out there, there are only two things I didn't like - the noise output and runtime.

While this one can be attached to a hose for continuous use, I don’t really know a lot of people willing to run a hose to their portable air conditioner in an apartment.

So, you’ll be stuck with only a few hours (up to 4, but realistically 3) of cooling.

Also, this portable AC gets rather loud at full speed - especially if you are near it. I found myself shouting on more than a few occasions, trying to talk while this evaporative cooler was running, so keep that in mind.

Compared to other portable air conditioners that don't require venting, this one's a winner 9 times out of 10.

Who is HESSAIRE MC37M best for?

The HESSAIRE MC37M is best for anyone with a large but still stuffy space that needs cool air.

Pros

  • Very effective at cooling larger spaces
  • Performance is comparable to central air conditioning units
  • Energy efficient option for both indoor and outdoor operation
  • A very affordable product for cooling power
  • Long-lasting and durable if maintained properly

Cons

  • Loud on high setting
  • Lacks additional features
  • 1-year warranty
  • Limited runtime could be a problem for many

2. HESSAIRE MC61V (Best High-End)

Ease Of Use

4.0

Cooling Ability

4.0

Value For Money

4.0


Overall Rating

4.0

CFM Airflow

5300

Room Size (Cooling Area)

Up to 1500 sq ft

Water Tank Capacity

14 gallons

Runtime

Up to 4 hours

Power Consumption

430 W

Noise Level

65 dB

Warranty

2 years

This high-end windowless air conditioner is nothing short of a beast, and if it weren’t for our top pick - this one would probably get it.

However, this one's for large spaces only, and that's why I can't crown it the best windowless air conditioner. Still, a vice-champion is also a heck of an achievement.

The reason I'm praising this one right off the bat is that I've had the pleasure of testing this one for two weeks, and wow, did it blow me away!

Its 5300 CFM fan and the ability to easily cool down up to 1500 sq ft make it one of the most powerful portable air conditioners I’ve ever tested.

In fact, I’ve had it out on the patio for an entire afternoon, and it literally felt cozy even though it was 100 degrees outside.

So, I can easily see this one cooling down large apartments, warehouses, or even a whole crew of buddies when they’re barbecuing or camping.

As for indoors, it managed to drop the indoor air temperature by 28 degrees, which is a massive difference.

One thing I always appreciate with high-CFM fans is the oscillating function, and thankfully, this one has it, too. The reason I want this is because standing in front of a powerful fan does not feel good, regardless of how hot it is.

Also, while the energy consumption isn't up to par with Hessaire MC37M, this one still does a pretty good job of being energy efficient.

From what I've seen, it draws around 430W, which is brilliant compared to other portable AC units on our list, like Portacool Jetstream 230.

Now, this is not a quiet operation by any means. It’s louder than central air units and quite a few other air conditioners on our list, with noise output reaching over 60 dBs.

Also, while its water reservoir is pretty large, due to its high cooling capacity, I don’t think you’ll get more than 4 hours of self-contained use. I know I didn’t.

On a more pleasant note, you can equip this one with a hose (which I suggest you do because it’s pretty easy to do) and have it run continuously.

Finally, here’s my biggest problem with it - it’s impossible to use in small spaces. It won’t take more than an hour for your room to become a swamp, so keep the space large and windows open.

Who is HESSAIRE MC61V best for?

The HESSAIRE MC61V is the best choice for anyone who wants performance and isn't afraid to pay a bit extra.

Pros

  • Up to 30 degrees drop in temperature
  • Energy Efficient for large areas
  • Powerful oscillating fan and three fan speeds
  • Can be equipped with a hose for non-stop use

Cons

  • Limited runtime of up to four hours
  • It can raise humidity levels quite fast
  • Sound output can be bothersome

3. Portacool Jetstream 230 (Best for Windowless Garages, Gyms, & Workshops)

Ease Of Use

4.5

Cooling Ability

4.5

Value For Money

4.1


Overall Rating

4.4

CFM Airflow

3600

Room Size (Cooling Area)

Up to 800 sq ft

Water Tank Capacity

30 gallons

Runtime

Up to 4 hours

Power Consumption

913 W

Noise Level

Up to 70 dB

Warranty

3 years

While its imposing looks will surely turn some heads, this portable air conditioner is much more than a pretty casing.

Easily outperforming some top-notch dual-hose model portable air conditioners (or even some central air conditioners), the Portacool Jetstream 230 is a splendid choice if you need to drop the air temperature in your gym or a garage and you don’t have window units installed.

What I saw from this one during the testing is temperature drops anywhere from 15-25 degrees depending on the outside conditions, which, as you know, is a difference between boiling in your skin and putting on a long-sleeve henley.

Where you'll definitely need that henley is if you find yourself in front of the best portable air conditioner.

With the fan ramping up to 3600 CFM, I don't see how you can comfortably stand in front of a gust of chilly air without feeling like you're in a mild storm.

Jokes aside, unlike the other portable air conditioners on the list we already mentioned, this one’s best used in large spaces, so I wouldn’t recommend trying to chill a bedroom (or even a small apartment) with it - for two reasons.

One - it’s way too powerful, and two - it’s very, very noisy.

We'll get to the noise in a bit, but now, let's focus on some other drawbacks because despite its mighty cooling capacity and coverage (up to 800 sq ft), this one's actually flawed in a few places from what I saw.

Firstly, this evaporative cooler will obliterate its 30-gallon tank in about four hours, and I really don't want to refill that much water three to four times a day.

Additionally, compared to the best portable air conditioner on our list - the Hessaire MC37M - this one’s 5 times more expensive and offers the same performance.

While I haven't had this problem, research showed many people complaining about the pump, which tends to die occasionally, so keep that in mind.

Thankfully, you do get a 3-year warranty, which will protect your purchase for the time being.

And finally, the reason why I said this one’s mostly for commercial spaces like gyms and garages is because it is loud and draws nearly a kilowatt of energy every hour - so you’ll need to bring some money in to keep the cost bearable.

Who is Portacool Jetstream 230 best for?

Portacool Jetstream 230 is one of the best portable air conditioners for large commercial spaces.

Pros

  • A very capable evaporative cooler that can easily chill large places
  • Performance-wise, it is comparable to traditional air conditioners
  • Well-built construction that will last
  • Oscillating louvers help disperse cold air evenly
  • Comes with a 3-year warranty

Cons

  • Model has a history of faulty pumps
  • Quite expensive
  • Not the easiest thing to keep clean due to the water tank drain design-flaw

4. HESSAIRE MC18M (Best Budget)

Ease Of Use

3.5

Cooling Ability

4.5

Value For Money

4.0


Overall Rating

4.0

CFM Airflow

1300

Room Size (Cooling Area)

Up to 350 sq ft

Water Tank Capacity

4.8 gallons

Runtime

4 hours

Power Consumption

85 W

Noise Level

53 dB

Warranty

1 year

Call me biased if you want, but Hessaire MC18M is my favorite portable air conditioner of all time.

I’ve had it in my workshop for well over three years at this point, and unless I end up needing something bigger - I’ll probably choose this or VAGKRI 2100CFM for my workshop.

This is the best portable air conditioner because it offers the best price-to-value combo you'll probably ever come across. I'm not just talking about its cooling ability and energy efficiency. This is a full package.

For less than $200, you get a portable air conditioner that can comfortably chill any space up to 350 sq ft while drawing 85 watts of electricity while being quieter than a mouse.

Okay, maybe it’s not THAT quiet, but it definitely won’t bother you.

This one has a decent 1300 CFM fan that will get the air moving. If positioned properly, you'll get a similar airflow to a window unit, only with that cold air feeling helping you power through a hot day.

Also, seeing how this is a pretty small unit with a rather tiny reservoir, one of the most important factors, portability, isn't compromised here - that is, if you don't mind the 4-hour run time.

Speaking of 4-hour runtime, it's interesting how 4.8-gallon and 30-gallon portable air conditioners (Jetstram 230) seem to run the same, huh? We'll touch on this a bit later.

Having only two fan speeds to choose from also makes me happy because it makes using it effortless - especially seeing how there’s no remote control here, and you do get to choose between fan-only and cooling modes.

Personally, I prefer the cooling mode because I use it in a workshop, and I have it connected to a hose, because unlike some other portable units, running this one on “cool” mode doesn’t mess up its energy consumption.

On the other hand, I do have to tell you about a few things that could be better.

Since it can be used indoors to cool down and circulate air around the stuffy room, not having a remote controller, timer, and other neat features makes it a bit underwhelming.

Also, while it is quiet, I don't think it's particularly comfy to sleep near, as 50-something decibels is quite audible.

I also don't think you should sleep near it because it can only run for about four hours without a hose, which means it won't be able to cool you down throughout the night.

And finally, I learned this the hard way - the hose connector you get in a box is very sharp. Please use gloves when attaching this portable air conditioner to a hose. Otherwise, you might cut yourself.

Who is HESSAIRE MC18M best for?

HESSAIRE MC18M is best for those looking to cool rooms on a budget.

Pros

  • Balance of energy consumption and the cooling ability
  • Very easy to set up and install
  • Long-lasting and budget-friendly
  • Designed for both indoor and outdoor use
  • Quiet operation

Cons

  • Limited additional features like remote control, timer, etc.
  • Sharp hose connector
  • Only a year-long warranty

5. Honeywell CO30XE (Best for Bedrooms)

Ease Of Use

3.5

Cooling Ability

4.0

Value For Money

4.5


Overall Rating

4.0

CFM Airflow

525

Room Size (Cooling Area)

Up to 250 sq ft

Water Tank Capacity

7.9 gal

Runtime

Up to 8 hours

Power Consumption

288 W

Noise Level

Up to 60 dB

Warranty

1-year

While Hessaire MC18M is my number-one budget-friendly portable air conditioner, Honeywell CO30XE comes in a close second.

So, what makes this special?

Well, if you were looking for portable air conditioners that you can run all night while you sleep - you've found one. This lovely-looking air conditioner can run for up to eight hours straight if you fill up its 7.9-gallon tank.

What also makes it a near-perfect air conditioner for a bedroom is that it is not overpowering like some other evaporative coolers on our list, namely Jetstream 230 and Hessaire MC61V.

Instead, you get a mild 525 CFM fan that can chill down a small, 250 square feet room to your desired temperature.

Now, don't get me wrong. You won't be able to chill your bedroom to an ideal 65-degree temp for sleeping, but you'll get pretty close. I managed to chill mine to around 75 on a nice evening.

The main reason why this air conditioner wasn’t as highly rated as the previous one is that its energy consumption, while very good (288 W), still isn’t as great as it should be considering its power or lack thereof.

For what it offers, paying around $500 in electricity annually isn't exactly great.

When it comes to energy efficiency, this one’s closer to powerful evaporative coolers, such as Hessaire MC37M, rather than MC18M, and that’s kind of an issue in my book.

Still, on a bright note, you won't have to worry about air quality in your bedroom with this one due to some primo carbon dust filters that can be removed and cleaned in about 2 minutes.

Just remove the front grill cover, take out the filter, and wash it every two weeks. Replace it after a year, and you should be golden.

And in the end, we finally have a portable air conditioner with every nice feature you might need.

Remote control, 3 fan speeds, low water alarm, timer, adjustable humidification dial, and an ice compartment on the top for better cooling - you have it all.

On a not-so-positive note, if you decide to run it on cool mode with fans on the highest setting - it will get as loud as 60 dB, and you probably won’t be able to fall or stay asleep.

My suggestion? Keep it on low, as you would do with all evaporative coolers that would be in your bedroom or other smaller rooms.

Who is Honeywell CO30XE best for?

The Honeywell CO30XE is best for those looking to cool down in small spaces without spending a lot.

Pros

  • One of the most affordable evaporative coolers on the market
  • A very long runtime, perfect for all-night use
  • Comes with remote control, timer, and additional features
  • Compact size and nice design
  • A lovely choice for indoor use

Cons

  • Energy efficiency could be better at this power capacity
  • Too loud when on high

6. VAGKRI 2100CFM Air Cooler

Ease Of Use

4.5

Cooling Ability

4.5

Value For Money

4.5


Overall Rating

4.5

CFM Airflow

2100

Room Size (Cooling Area)

Up to 600 sq ft

Water Tank Capacity

8 gallons

Runtime

Up to 12 hours

Power Consumption

105 W

Noise Level

Up to 60 dB

Warranty

2 years

VAGKRI 2100CFM Air Cooler is one of those portable air conditioners you don’t tend to acknowledge until you compare it to other portable AC units, and truth be told, I’m guilty of it myself.

I didn’t pay attention to it until my buddy got one, but once I did, boy, did I fall in love with it.

It’s arguably more efficient than almost every window unit you can find out there. While window units offer a similar level of cooling, they can’t possibly match VAGKRI’s energy efficiency of only 105 W per hour.

Just like MC18M, this one won’t spend more than $150-200 dollars annually, making it one of the kings of energy efficiency.

With a 2100 CFM fan and a coverage area of up to 600 sq ft, you can comfortably cool rooms in any open-concept apartment.

And the best part? You can do it for a REALLY long time.

From what my buddy had told me, he routinely manages to get around 9 or 10 hours of self-sufficient runtime from this bad body, and I think its 8-gallon water reservoir has a lot to do with it.

Even on full blast, this one offers the convenience comparable to portable air conditioners with exhaust hoses.

And sure, it won't cool rooms continuously (although it could because there is a water hose connector), but having a windowless portable air conditioner work for ten hours straight is a rare sight.

In addition, this air conditioner has a remote control, which you can use to control fan speeds, and an oscillating fan right from your couch.

You can also set the timer, get alerted when the water level is low, and even get the ice trays to make this puppy cool you even better.

On the other hand, the sound output can be a little bit overwhelming when you’re running high fan speeds, and smaller rooms could get humid quickly, but as long as you keep this air conditioner in the right spot and your place has enough airflow - it should be more than fine.

One complaint I saw people having is the water pump sometimes refuses to run. My buddy says he hadn’t had problems with it, but from what I saw online, several people did.

Who is VAGKRI 2100CFM Air Cooler best for?

The VAGKRI 2100CFM Air Cooler is best for everyone looking to get an all-around great air conditioner for both indoor and outdoor use.

Pros

  • Exceptional energy efficiency
  • 120° oscillating fan for greater and more pleasant coverage
  • Can run up to 12 hours
  • Remote and a 24-hour timer
  • Despite the manufacturer’s claims, it also performs great outdoors

Cons

  • Finicky water pump
  • Sound output can get up to 60 dB
  • It can easily raise humidity in smaller spaces

7. Pioneer WYS012A-20 (Best Ductless Mini Split AC + Heater)

Ease Of Use

4.0

Cooling Ability

4.0

Value For Money

4.0


Overall Rating

4.0

CFM Airflow

12,000

Room Size (Cooling Area)

Up to 450 sq ft

Water Tank Capacity


Runtime

Continuous

Power Consumption

600 W

Noise Level

26 dB

Warranty

5 years

I understand that this isn’t an air conditioner like the ones before it, but there’s a good chance you may live in a humid environment, and you might need something with a built-in dehumidifier mode to get you through the hot summer day, and this is it.

As you can see, this is a mini-split air conditioner, meaning that it isn’t portable and it requires professional installation.

The reason why this one is included in this list is that it is an inverter air conditioner, meaning it will consume less energy than regular air conditioners. In fact, it’ll consume less energy than Jetstream 230, but we’ll get to that in a second.

Let’s start with the basics.

This is a 12,000 BTU rating (British thermal units) and 20 SEER (seasonal energy efficiency ratio) air conditioner, meaning it’s neither weak nor super powerful.[1]

A middle-of-the-road air conditioner, if you will.

What these numbers mean in real life is that this air conditioner will be able to chill up to 450 square feet regardless of the temperature or humidity of the room, all while consuming only 600 watts per hour.

That's great as far as full-sized air conditioners go!

What this air conditioner also does is warm up your space, dehumidify it, and even vent it - all pretty common features for a mini-split.

Another massive advantage this one has over the rest of the air conditioners on our list is it is much quieter than all of them.

While it certainly wouldn’t call it inaudible, it is quiet enough to comfortably sleep while it runs on the highest setting.

One thing you must know is that you can't install this one all by yourself. The installation will require some electrical knowledge, so please don't dabble with it if you don't know what you're doing.

And, just so you're not like, "This is the best AC ever," - there have been some reports of it being short-lived.

While I personally haven't received any calls (even though my parents-in-law have this one, and you know how family loves asking for help when things go wrong), some people have experienced issues, so keep that in mind.

Who is Pioneer WYS012A-20 best for?

Pioneer WYS012A-20 is best for anyone looking for more than just a windowless air conditioner in their home.

Pros

  • Excellent energy efficiency for a full-sized AC
  • Works in both humid and dry climates
  • Suitable for any room of your house
  • Quieter than a fridge
  • Considerably lower maintenance compared to windowless ACs

Cons

  • Requires professional installation
  • Does not appear to be long-lasting
  • Not the best option for heating your home
  • Draws more energy than most other picks

Windowless ACs Compared

Image
Portable Swamp Coolers - 3100 CFM MC37M...
Hessaire MC61V Portable Evaporative Cooler,...
Portacool PACJS2301A1 Jetstream 230 Portable...
Portable Swamp Coolers - 1300 CFM MC18M...
Honeywell 525 CFM, White Indoor Portable...
Evaporative Cooler, VAGKRI 2100CFM Air...
Model
Portable Swamp Coolers - 3100 CFM MC37M...
Hessaire MC61V Portable Evaporative Cooler,...
Portacool PACJS2301A1 Jetstream 230 Portable...
Portable Swamp Coolers - 1300 CFM MC18M...
Honeywell 525 CFM, White Indoor Portable...
Evaporative Cooler, VAGKRI 2100CFM Air...
CFM Airflow
3100
5300
3600
1300
525
2100
Cooling Area
Up to 800 sq ft
Up to 1500 sq ft
Up to 800 sq ft
Up to 350 sq ft
Up to 250 sq ft
Up to 600 sq ft
Tank Capacity
10.3 gal
14 gallons
30 gallons
4.8 gallons
7.9 gal
8 gallons
Power Consumption
250 W
430 W
913 W
85 W
288 W
105 W
Noise Level
Up to 60 dB
65 dB
Up to 70 dB
53 dB
Up to 60 dB
Up to 60 dB
Image
Portable Swamp Coolers - 3100 CFM MC37M...
Model
Portable Swamp Coolers - 3100 CFM MC37M...
CFM Airflow
3100
Cooling Area
Up to 800 sq ft
Tank Capacity
10.3 gal
Power Consumption
250 W
Noise Level
Up to 60 dB
Price
Image
Hessaire MC61V Portable Evaporative Cooler,...
Model
Hessaire MC61V Portable Evaporative Cooler,...
CFM Airflow
5300
Cooling Area
Up to 1500 sq ft
Tank Capacity
14 gallons
Power Consumption
430 W
Noise Level
65 dB
Price
Image
Portacool PACJS2301A1 Jetstream 230 Portable...
Model
Portacool PACJS2301A1 Jetstream 230 Portable...
CFM Airflow
3600
Cooling Area
Up to 800 sq ft
Tank Capacity
30 gallons
Power Consumption
913 W
Noise Level
Up to 70 dB
Price
Image
Portable Swamp Coolers - 1300 CFM MC18M...
Model
Portable Swamp Coolers - 1300 CFM MC18M...
CFM Airflow
1300
Cooling Area
Up to 350 sq ft
Tank Capacity
4.8 gallons
Power Consumption
85 W
Noise Level
53 dB
Price
Image
Honeywell 525 CFM, White Indoor Portable...
Model
Honeywell 525 CFM, White Indoor Portable...
CFM Airflow
525
Cooling Area
Up to 250 sq ft
Tank Capacity
7.9 gal
Power Consumption
288 W
Noise Level
Up to 60 dB
Price
Image
Evaporative Cooler, VAGKRI 2100CFM Air...
Model
Evaporative Cooler, VAGKRI 2100CFM Air...
CFM Airflow
2100
Cooling Area
Up to 600 sq ft
Tank Capacity
8 gallons
Power Consumption
105 W
Noise Level
Up to 60 dB
Price

Factors To Consider When Buying A Windowless Air Conditioner

While I'm very satisfied with the products recommended above, I would never want you to blindly choose a windowless air conditioner - whether that be from a store or a buyer's guide like this one.

Instead, I'll give you all the information you need in order to make the best purchase for your particular situation.

Climate Conditions & Use-Case

The first thing I want you to understand is that a windowless air conditioner, while undisputably useful, isn't great for any scenario.

Even the best windowless air conditioner can only do its job in hot and dry climates like Nevada or Arizona. On the other hand, if it's hot and humid - it won't work properly (but that’s why I included Pioneer WYS012A-20 up there).[2]

You see, a windowless air conditioner doesn't work with a refrigerant to cool the air as some dual-hose or single-hose units do. A windowless air conditioner uses water or ice.

To be more precise, it relies on the evaporative process (hence the other name, evaporative cooler) to cool down the room.

How this works is the hot air goes over water-soaked pads inside the AC unit, which makes the water evaporate, effectively cooling the air. However, this also means that if the air is already damp, the water-soaked pads won't be able to introduce additional moisture to it, rendering them virtually unusable.

Still, there's another "issue" at play here.

You see, despite its name, a windowless air conditioner isn't exactly the ideal air conditioner for a windowless room.

Since it doesn't come with an exhaust hose or a vent, that same moisture is expelled right back right into the room, making the space feel like a Florida swamp on a hot August day.

Besides the terrible moisture, this also means that your portable air conditioner will also become less and less efficient due to the reasons I outlined above.

However, here's where it gets A LOT better.

If you live in a hot and dry climate, and you intend on using your windowless air conditioner in a garage or a workshop (like I do), on your deck or a patio, or even in your open-concept apartment with a lot of airflow - this thing will shine.

From what I've seen over the years, you can expect temperature drops up to 30 degrees - which we can all agree is life-changing.

Cooling & Airflow Capacity

Once you start dipping your toes into the world of air conditioners, you'll find terms like BTUs - British Thermal Units - which measure cooling capacity.[3]

However, when it comes to windowless air conditioners, this standard of measurement gracefully bows out.

Instead, the cooling prowess of these contraptions is denoted by their coverage area - the size of the room or space they can effectively cool.

As you saw above, different models boast various capabilities, with some even capable of maintaining a comfortable atmosphere in areas as large as 1500 sq ft (we're looking at you, Hessaire MC61V).

Now, this subtle change in measurement means you need to approach your buying decision a bit differently.

Your prime concern? The size of your space.By knowing the square footage you aim to cool, you can effectively sift through the range of windowless AC units, selecting the one that meets your requirements.[4]

Yet, I want you to keep in mind the golden rule of consumer wisdom - skepticism.

If a unit declares a coverage of "700 sq ft", perhaps more realistically, interpret it as "500-600 sq ft", as optimal cooling conditions (which is how these things are tested) are rarely mirrored in real life.

Next up, we have the airflow capacity, measured in cubic feet per minute (CFM).[5]

Essentially, a high CFM equates to a cooler space as more air is circulated per minute, enhancing the cooling performance.However, don't be misled into a 'bigger is better' narrative. I've seen many make this mistake only to regret it hours later.

Overdoing it with a massive CFM rating, such as the Hessaire MC61V with a CFM of 5300, isn't always the smart move if you don't have the space for it.

Yes, a high CFM windowless air conditioner can move more air, but it also brings a ton of potential drawbacks.It could (read: will) be noisier, cause uncomfortable drafts, and potentially be a massive stain on your electricity bill.

Remember, efficiency isn't only about power. A prime example is the Portacool Jetstream 230, which despite a lesser CFM of 3600 compared to Hessaire MC61V’s 5300, requires double the electricity!

Honeywell dehumidifier on wooden floor

Tank Size & Runtime

Speaking of cooling ability and efficiency, windowless air conditioners, unlike their central air counterparts, can't deliver a steady stream of cooling all day long.

Instead, what you can expect is a several hours-long break from the heat.

And I know what you mean - this 'runtime' is intertwined with the capacity of the water tank that feeds the unit. A larger tank offers a longer runtime, right?

Well, it's a bit more nuanced. The capacity of a water tank in a windowless air conditioner does play a role in the runtime, but not as directly as one might assume.

For instance, larger tanks are typically found in units designed for larger spaces, which require more water to efficiently drop the temperature. So, while the tank size matters, it doesn't linearly correlate to longer cooling periods.

As you saw earlier, tanks range from compact 2-gallon (Hessaire MC18M) variants to sizeable 30-gallon (Jetstream 230) behemoths, and if you recall, both of these have a 4-hour runtime.

However, most windowless air conditioners sport tanks within the 4 to 8-gallon range, which in some way, provides a pretty optimal blend of portability and functionality.

So what does this mean for runtime? In general, an average windowless air conditioner offers a cooling span of about 3 to 6 hours. And from what I've seen, anything surpassing five hours is a good deal.[6]

This also means that replenishing the water tank will be a regular chore, but that's part of the package.To be fair, there's a workaround that involves connecting a hose for a steady water supply, though this restricts the unit to outdoor use only.

Size & Portability

As I’m sure you’ve noticed, a windowless air conditioner is a portable air conditioner - but without the window kit. So, it’s actually more portable than the average portable air conditioner.

Since they don’t come with an exhaust hose, they can be placed basically wherever (as long as the conditions allow it), so they’re essentially what a portable air conditioner should be.

Another reason why they’re so portable is that they’re usually quite compact, as are most portable air conditioners.

They’re often the size of a suitcase or a mini-fridge (or even smaller), so it’s highly unlikely you won’t be able to find the space for it.

That said, there are some beefy units out there, like the Portacool Jetstream 230, but as you saw, those puppies weren’t designed with living spaces in mind.

Long-term Reliability

Look, I won't sugarcoat it - these, generally speaking, aren't the most reliable AC units you can get your hands on, especially when compared to central system AC units.

As you probably saw, there are countless stories about windowless air conditioners that bite the dust after only a year or even a few months of use. And quite frankly - those are far more common than they should be.

However, before you throw in the towel and just decide to "sweat it out," let me share three solid tips that can help you snag a windowless air conditioner that's not only reliable but can also go the distance:

  • Always opt for well-established brands and trustworthy sellers
  • Go for units that come with multi-year warranties
  • Treat them right

Going for a well-established brand, like Hessaire, typically means you’ll be able to get your hands on quality products that stand the test of time. If that weren’t the case - they wouldn’t be around for all these years.

Also, buy from reputable sellers. I can’t tell you how many calls I’ve received because someone bought a used or faulty AC, and they didn’t even know it.

Next, if a manufacturer is ready to back up their product with a two or three-year warranty, that's usually a good sign that they believe in the durability of their product. Once again, you’ll only get to enjoy these benefits if you shop in the right place and go for the right product.

And finally, you have to stay on top of maintenance. Quite honestly, user error is usually the main cause of most failures.

We’ll tackle the maintenance in a bit, but for now, just keep in mind that if you let your portable air conditioner lose water frequently - you probably won’t have it around for a long time.

Hessaire Portable Evaporative Cooler

Price & Warranty

Keeping both price and warranty in mind when shopping is paramount.

As you saw above, the list of products I presented you features air conditioners that are around $200, such as Hessaire MC18M, and those that are more than $1500, such as Jetstream 230.

However, most of the time, you’ll be looking to spend around 300-500 bucks for a no-vent air conditioner that will offer both functionality and performance.

As for the warranty, you can expect most of these air conditioners to come with a 1 or 2-year-long warranty.

I’m usually not a fan of 1-year warranties, as they’re not exactly confidence-inspiring, but as luck would have it, the one I own is a single-year-warranty product, and I haven’t had any issues with it for several years.

However, as a general rule of thumb, I'd look for a 2-year warranty, just to make sure you're covered.

Noise Levels

Compared to traditional century system air conditioners, windowless portable air conditioners aren’t the quietest, which could be an issue for some - depending on where you want to use these.

Generally speaking, you’ll want to look for a windowless air conditioner with a noise level below 60 dB, which is right around where conversations take place. In other words, you’ll want a portable AC unit that won’t interfere with your conversations.[7]

That said, this shouldn’t be too hard, as most windowless portable air conditioners operate at 50-70 dB, depending on fan speeds and cooling mode. As you can imagine, the more powerful units with more CFM tend to be a bit louder, but if you’re using them outside, I think it won’t pose a problem.

Indoors, however, these might interfere with your afternoon naps unless you enjoy louder white noise.


How Do Windowless AC Units Work? (Venting Explained)

As we briefly mentioned, at the heart of these units lies a principle we're all familiar with from everyday life - evaporation. When water evaporates, it absorbs heat, producing a cooling effect.

This is why you feel cooler when sweat evaporates from your skin, for example.

Now, this evaporative cooling process is the exact same concept that drives windowless air conditioners. These devices suck in hot, dry air from your surroundings and pass it over a cooling pad soaked in water. As this air moves over the cooling pad, the water begins to evaporate, absorbing heat from the air in the process.

This results in a cooler but more humid breeze that is then blown back into your space.The catch is, as we said earlier, that the effectiveness of windowless air conditioners is highly dependent on humidity levels.

The evaporative cooling process works best in dry environments where the air can readily absorb more moisture. When the air is already heavy with moisture (think above 65% relative humidity), there's less room for additional water vapor, leading to reduced cooling power.

Hessaire MC18M Portable Evaporative Cooler

Care, Safety & Maintenance

Caring for your windowless air conditioner (or evaporative cooler) is vital for both its longevity and efficient operation.

Firstly, regular refilling of your unit is key to its operation. Without a sufficient supply of water, these coolers can't perform their cooling magic. Also, they tend to break if they run dry, so please, keep an eye out for the tank.

Cleaning or replacing filters is another important task. Filters help to ensure the air circulated by your unit is clean. Over time, these filters can accumulate dust and other airborne particles, which may impair the unit's cooling efficiency, and also pose a few health issues.

Emptying and drying the tank is also essential to prevent water from stagnating and possibly leading to mold growth.

As with any appliance that uses water, cleanliness is paramount. Regularly wiping down your unit, particularly the water tank (or sometimes the drain tank), can help prevent the buildup of mold and mildew.

Lastly, and arguably most importantly, just follow the manufacturer's instructions. 10 times out of 10, you’ll find everything in there.


People Also Ask (FAQs)

Why does a portable AC need to be vented?

A portable AC unit needs to be vented because it extracts hot air from the room while cooling it.

Without proper ventilation, the hot air would remain in the room, counteracting the cooling effect of the air conditioner, which would essentially render the unit ineffective in lowering the room temperature.

Can I use a portable air conditioner in a room without a hose?

You can't use a traditional portable air conditioner in a room without a hose because they require it to vent the hot air they extract from the room to the outside.

However, "ventless" or "evaporative" portable air coolers, which don't function in the same way as traditional air conditioners, can be used without a hose.

What happens if the air conditioner is not vented properly?

If a portable air conditioner is not properly vented, it won't be able to efficiently cool the room.

Since the unit works by pulling in warm air, cooling it, and then expelling the hot air outside, if that hot air isn't effectively vented through an exhaust hose, it will remain in the room, causing the overall temperature to stay the same.

Are fans a better choice than air conditioners for rooms without windows?

Fans can be a good choice for rooms without windows because they help circulate air and can make a room feel cooler without the need for venting.

However, fans don't actually lower the temperature of the room. They simply create a cooling effect by moving air over your skin.

If the room is very hot, an air conditioner or an evaporative cooler could be a better option, but then again, you have to keep venting in mind.


Summary – Which Should You Buy?

So, which windowless air conditioner should you buy? I can't make that decision for you, but Hessaire MC37M truly is the best all-rounder and arguably the best bang for your buck, bar none.

On the other hand, Hessaire MC18M and Honeywell CO30XE are both top-notch choices for even less, so if you’re just trying out these air conditioners without exhaust - you may even want to start there.

The truth is, whether you go budget-friendly or high-end like Hessaire MC61V, I can’t imagine you’ll make a wrong choice with my list of the best portable air conditioners.

Editor’s Choice For Windowless Air Conditioners

Ease Of Use

4.4

Cooling Ability

4.2

Value For Money

4.2


Overall Rating

4.3

References: 

  1. https://jacobsheating.com/blog/seer-rating/
  2. https://www.usgs.gov/media/images/evaporative-coolers-work-best-dry-areas-us-area-a
  3. https://en.wikipedia.org/wiki/British_thermal_unit
  4. https://www.puravent.co.uk/calculator/evaporative-cooler
  5. https://www.energy.gov/energysaver/evaporative-coolers
  6. https://hvacrguy.com/evaporative-cooler-average-water-intake-and-how-to-improve-it/
  7. https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html
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Josh Mitchell

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Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

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Midea U Shaped Window Air Conditioner

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