Photo of Ventless Air Cooler in a Room
Image of Luma Comfort EC110S

There are many ways to cool a room inside your home and make it more comfortable for your guests.

When conditions are right, one of the most economical and efficient systems is evaporative air cooling.

Despite being a practical solution to cooling even tricky spaces, few people are aware of how evaporative air coolers works or their many benefits.

Below we go into the details to explain exactly what these devices are, how they work, and whether or not you should consider getting one.

The Basics of Evaporative Air Coolers

Evaporative Air Coolers can (depending on their size) cool an area from 120 square feet to 2,000 square feet.

All these machines require is a supply of water and electrical power.

Evaporative air coolers are often called ventless coolers because they do not require a vent like traditional air conditioners and HVAC systems.

(Here is a complete guide on how to buy the best ventless air conditioner for your home.)

Instead of providing refrigerant air, evaporative air coolers provide cooled air.

How does this happen?

Keep reading.

The Science behind How Ventless Air Cooling Units Work

When you’re on a hot beach, what is the best way of cooling down?

Going into the water of course!

This seems like common sense but it is important to explaining how evaporative air cooling units work.

You see, along with decreasing your core temperature, the water in the ocean will cover your body and saturate your skin.

Ever notice that when you walk out of the ocean (or pool, bath, etc.) it feels cooler?

Even flight breezes can become noticeable.

The reason for this has to do entirely with evaporation.

Evaporation is the process of water turning from a liquid to a gas.  The act of changing states requires a great deal of energy, decreasing the immediate temperature as a result.  When the moisture is on your skin and it evaporates, you feel the cool temperature created by the energy being removed from the air.

This simple act of physics is how ventless air cooling units work and the main reason why they are so effective.

Another way to understand the process is by considering the air like a sponge.  It operates in a similar manner.

As air comes in contact with water, it absorbs the water and becomes damp, thus humid air is created.

In a dry condition where the humidity (the amount of moisture in the air) is small, more moisture can be absorbed.

In wet conditions, the air is already wet and can’t absorb much more.

When the humidity reaches around 100%, then it can no longer hold any moisture and the chance of rain is very high.

Amazingly enough, how hot the water is doesn’t improve or decrease the effectiveness of evaporative cooling.

A temperature difference of more than 50 degrees will result in only a 2 to 3% change in total.

By creating humidity in the air, a ventless portable air conditioner sets up a process that will decrease the temperature dramatically.

This process is simple and inexpensive when compared to other methods.

The drier the climate is, the more effective the system will be.

Such units can cool things from as small as a closet to as large as an apartment complex.

How Evaporative Air Coolers Are Designed

Evaporative coolers are designed in such a way as to suck in the air through wet filter pads located on either side of the machine.

Fed from a water source, the pads add moisture to the warm air moving through them cooling the air temperature around them.

Typically, the larger the surface area, the more air can move through the filters and the more cool air can be produced.

See all of Amazon's Best Selling Ventless AC Units

Why Choose Ventless Air Coolers Over Other Types?

As mentioned above, ventless air coolers are quite effective in climates where the air is dry.

Requiring only a small amount of electricity and water, evaporative air coolers are quite friendly to the environment.

Finally, their low price and simple design mean the less money you have to spend to make a space the ideal temperature.

If you’re looking for even the cheapest options available, we have a guide on cheap portable air conditioner under $200.

What Kind of Condition Is Best For An Air Cooler?

The first thing you will need is access to water and an electrical outlet.

The second thing you will need is a climate that is typically dry.

Finally, you will need some form of ventilation to move the moisture and air throughout the space.

Without those three requirements, running an air cooler may not be the best solution.

Now that you have practical knowledge of how air coolers work, you can determine whether or not air coolers are what you are looking for.

The Takeaway

  1. Only install evaporative coolers where you have good mechanical ventilation or natural ventilation
  2. The temperature of the water going into the ventless cooler does not make a noticeable amount of difference
  3. The drier the climate and lower the humidity, the better your evaporative cooler will perform. A space that has a relative humidity below 70% will work.
Avatar for David Morrison

About David Morrison

David is an Air Quality & Comfort Technician. He has expert knowledge on the technology and design of air purification, air conditioning, and heating systems. His main role is to write content that helps people get the most value out of their air purifiers, air conditioners, and heating units. (See Full Bio)