Let’s start this article on outdoor air conditioners with a newsflash:
There are no outdoor air conditioners.
An air conditioner is a specialized device that, based on the 2nd Law of Thermodynamics, facilitates heat exchange between two isolated spaces. Outdoors, in essence, is just one big space.
Don’t worry. If you’re looking to buy an outdoor air conditioner for the patio, deck, porch, and so on, you can. It’s just the terminology that is messed up. What we call outdoor or outside air conditioners are essentially big evaporative coolers. This is how they look like:
These evaporative air coolers work as a substitute for air conditioners outdoors. They use a natural process of water evaporation to generate a cold breeze.
Essentially, they create a cold breeze that can cool down a whole patio or just give you a little fresher air when outdoors.
The key specification that determines how good this kind of outdoor air conditioner is is the output airflow (measured in CFM or cubic feet per minute). Here is how the capacity of indoor/outdoor air conditioners is expressed:
- Indoor air conditioners use BTUs or tons (12,000 BTU = 1 ton) to express cooling capacity.
- Outdoor air conditioners use CFMs to express how well they cool outside spaces (patio, yards, even garages, workshops, etc.).
What size of an outdoor air conditioner you need depends on how big space you’re looking to cool down. Another important specification is the tank capacity. Outside AC units – the evaporative coolers – come with water tanks; the bigger the tank, the more cooling effect you will get from each water refill.
According to these key specifications, we can create a list of the best outdoor air conditioners. This is exactly what we have done, and you can see that there are two brands that dominate the outdoor AC market. These are:
- Hessaire. Specialized outdoor evaporative cooler brand; they make the best and more powerful outdoor AC units.
- Honeywell. General HVAC company that also produces portable outdoor air conditioners.
Below, you will find a comparison of their top-rated outdoor AC unit. You can compare specifications and, further on, read the reviews of the best models. We’re going to cover the specification basis of outdoor AC units, but if you’re in a hurry, you can just jump to the list and comparison of the best outdoor ACs here:
Let’s first look into how these “outdoor air conditioners” operate and how they are able to cool down whole patios. We will also talk about airflow (CFMs), cooling coverage that seems from CFMs, and, quite importantly, the size of the water tank that comes built-in the outdoor AC unit:
How Do Outdoor Air Conditioners Work?
Let’s take a regular air conditioner as an example. In the summer, it’s hot outside, and we would prefer a cool indoor air temperature. An air conditioner uses refrigerant and compressor to facilitate the transfer of heat outdoors.
That, of course, only works if we close all the windows. If we were to open the windows, the hot outdoor air would gush into our cool home.
That’s exactly what we can’t do outdoor. In this analogy, outside “all the windows” are opened. That why we can’t use a regular air conditioner; we use evaporative coolers.
These patio coolers use a water evaporation process to lower the temperature of input air and output cooler air. Because they blow out cool air, we like to consider them as outdoor air conditioners.
Water evaporation itself is an endothermic process; it requires energy to evaporate. It takes that energy from hot input air that, as a consequence, results in two things:
- Water gets the necessary energy to evaporate (turns into what we call humidity).
- Air is cooled in the process.
The cooled air is exactly what we are after when looking to cool down an outdoor patio with these AC-like units.
Picking The Best Outdoor AC Units: CFMs And Cooling Coverage
The first specification to check when comparing outdoor portable AC units is the maximum airflow. Airflow is a measure of how much cool air a given evaporative unit can blow out (it’s expressed in CFMs).
The higher the airflow, the better the outdoor AC unit will cool down our patios.
Smaller units with below 500 CFM are only used indoors. There it’s enough. Outside, the cool air we generate with these outdoor AC units has to compete with large amounts of hot summer air. That’s why having high airflow is essential.
The best outdoor air conditioners for patios, for example, generate 1000+ CFM airflow. This is to guarantee that you will actually have a cooler patio.
The amount of space any given outside AC unit can cover directly depends on airflow (the correlation is non-linear). Here are some ballpark figures on what airflow from an outdoor AC unit is recommended to cool down given square footage:
|Cooling Coverage (Sq Ft):
|300 sq ft
|600 sq ft
|900 sq ft
|1,550 sq ft
Does that mean that you can’t put a 5,000 CFM outdoor AC in a 500 sq ft patio?
Not at all. In fact, if you would really like to have a chill time on your patio, you are recommended to do just that.
Here the thing:
Nobody ever complains a patio is too cold. Everybody hates heaty sweaty patios.
Note: Choose a higher CFM outdoor AC unit. You will guarantee that the patio will be cool enough. If it gets too cold, just dial down the cooler. You can always do that; you can’t dial up an undersized evaporative cooler.
Bigger Water Tanks Are Better (Last Longer)
Outdoor AC units are pretty easy to operate. You can plug them in the outlet and press ‘On’. Most of them run on standard 110/120V and draw less than 500W of electrical power.
However, there is one key element to outdoor AC units that need to be refilled continually:
There are no water evaporative coolers without water. It takes electricity and water to generate the cooling effect outdoors. That’s why every portable outdoor air conditioner comes with a water tank.
Bigger units (with higher CFM) spend water quicker than small units; hence they have bigger water tanks. Regardless of the size, however, it’s recommended to go for as big a water tank as possible when choosing the best outdoor AC units.
A bigger water tank means that you will have to refill it less frequently. That’s the job every picnic-goer wants to avoid.
In general, avoid units with below 5-gallon tanks. Patio coolers with 10+ gallon tanks are much more sought after. Once you fill them up, you can have fun longer than with smaller-gallon coolers.
Considering all this, let’s look at which are the best outdoor air conditioners currently on the market:
Best Portable Outdoor Air Conditioners (Comparison)
1. Best Overall Outdoor Air Conditioner: Hessaire MC61M (5,300 CFM; Perfect For Patios)
|Up to 1,600 sq ft
|28″ x 17″ x 46″
Of all the outdoor AC manufacturers, the Hessaire is the best and most well-known brand. They specialize in producing powerful evaporative coolers that can cool down a whole patio. Their best outdoor air conditioner, and generally considered the best overall, is the Hessaire MC61M.
Hessaire MC61M is a powerhouse cooler that the outdoor environment needs. This is not your average 1000 CFM cooler. Hessaire MC61M can produce a total airflow output of 5,300 CFM. It’s one of the strongest outdoor ACs out there.
With 5,300 CFM, you can cool down outdoor spaces of up to 1,600 sq ft. That means that you can even put it in a 40 ft x 40 ft patio and adequately cool it down. In practice, most people use it to cool down 20 x 20 ft patios, BBQ places, and so on.
It has one of the biggest tank capacities of all the outdoor air conditioners on the market. You can fill it with a total of 14 gallons; that should last for a whole day of cool breeze even in bigger patios.
To generate the massive 5,300 CFM airflow, Hessaire MC61M uses 430 watts of power. That’s one drawback; to truly cool down larger patios, the Hessaire MC61M requires about the same amount of power as a laptop. Other units require about 250 watts in total.
All in all, Hessaire MC61M is the massive evaporative cooler that can easily cool down any outdoor patio. It’s hands down the most effective way to cool down outdoor spaces:
2. Top-Rated Popular Outside AC Unit: Hessaire MC37M (3,100 CFM)
|Up to 950 sq ft
|24″ x 16″ x 38″
Hessaire MC37M is the smaller (yet still very big) cousin of the massive Hessaire MC61M. It is more appropriate for a large array of outdoor activities such as grilling, sunbathing, and cooling down smaller and standard-sized patios.
It can produce a total of 3,100 CFM cooling airflow output. That might sound a lot less than 5,300 CFM MC61M can produce but it’s actually a lot more than the regular 1,000 CFM outside AC units Honeywell producers, for example.
It has a maximum cooling area of 950 sq ft. That, as we have discussed earlier, doesn’t mean you can’t put it near your pool area and enjoy its cooling breeze at a much smaller area (300 sq ft, for example).
It has a rather large 10.3-gallon tank capacity; which means less frequent refilling with water.
On top of it all, it doesn’t have the $500+ price tag like its bigger outdoor AC cousin.
The reason why Hessaire MC37M is so popular is that it can provide plenty of cooling effect for a very affordable price:
3. Best Honeywell Outdoor Air Conditioner: Honeywell CO48PM (1,062 CFM)
|Up to 6,10 sq ft
|15″ x 24″ x 34″
Honeywell is a brand that makes pretty much anything in HVAC. Luckily, it’s only one of the few companies that make big evaporative coolers for outdoors; and they actually made good ones that can cool outdoor areas like air conditioners.
Honeywell CO48PM is the best Honeywell outdoor air conditioner. It has a good 1,062 CFM airflow with a 610 sq ft coverage. If you check how big your patio, deck, BBQ area is, you can pretty much see if the Honeywell CO48PM will be enough to cool it down adequately.
The best thing about the Honeywell CO48PM is the airflow to the tank capacity. The tank has a 10.6-gallon capacity; that’s an oversized tank. Usually, outdoor AC units with about 3,000 CFM have 10+ gallon tanks.
Oversized tank capacity is excellent if you’re looking to enjoy a cooling effect throughout the day. You probably won’t have to refill it due to such a big water tank.
All in all, Honeywell CO48PM is the best Honeywell outdoor AC unit with oversized tank, 1,000+ CFM cooling output, and it’s available at a fair price:
4. Best Outdoor Air Conditioner For Sunbathing: Honeywell CO25AE (694 CFM)
|Up to 300 sq ft
|15″ x 19″ x 33″
Honeywell CO25AE is the best small outdoor air conditioner. It has less than 1,000 CFM cooling airflow (694 CFM, to be exact). As such it’s not appropriate to cool down whole patios. However, it’s the perfect way to cool during sunbathing or if you’re grilling outside.
With a bit over 25 lbs, this is also the most portable outdoor air conditioner. Anybody can move it around; from the pool to the grill area or any other place in your yard.
You can move it even when it’s full due to the smaller water tank. While bigger units have 10+ gallon tanks, this small outside air conditioner has a 6.6-gallon tank. It’s actually big considering the Honeywell CO25AE has only a 694 CFM output. The whole point is that you can move it around even with a full tank.
It does require 235 watts to run and it’s not exactly energy-efficient. It’s convenient and very easy to use but it draws quite a bit of power.
All in all, Honeywell CO25AE is the best small portable outdoor air conditioner. Too small for patios but perfect for grilling or sunbathing:
This is the summary on “outdoor air conditioner”. This is what we call these bigger evaporative coolers. There give us a way to enjoy a cool breeze even when we’re outdoors.