The Basics

What is an evaporative air cooler? 

An evaporative air cooler uses evaporation - the conversion of water into water vapor - to fan out a cool breeze and lower air temperatures. Its cooling power is more robust than a standard fan, yet it still consumes minimal energy. Evaporative air coolers are also known as swamp coolers, desert coolers or wet air coolers, and are most effective in hot, dry climates. The sensation is like a lakeside breeze—a cool wind with a hint of moistness.

How do evaporative air coolers work?

Evaporative air coolers include two motorized components: a pump and a fan. The pump circulates water around the unit and saturates a honeycomb-shaped irrigation pad. The fan blows air through the wet irrigation pad, causing the moisture to evaporate into vapor. The conversion of heat energy into evaporative energy results in a coolness in the outgoing air. An example of this is felt in a lakeside breeze: the air along a lake or waterfall feels cooler than the air inland. This is because heat has been converted into water vapor.

What is the honeycomb cooling media?

Most modern evaporative air coolers use a proprietary Honeycomb Cooling Media. This matrixed irrigation pad is the powerhouse behind the evaporative cooler. Its extensive surface area allows for ample water saturation, which in turn offers plenty of evaporation and evaporative cooling.

Are air coolers used indoors or outdoors?

Evaporative air coolers are available in a wide range of models for different environments, with models available for indoors and/or outdoors. Outdoor coolers are constructed with weather-resistant materials, making them withstand rain, direct sunshine and UV rays. Many larger outdoor models are also equipped with a continuous water connection, allowing you to connect your garden hose for automatic tank refills and for extended operation. Indoor models could be used in all indoor living areas as well as enclosed outdoor areas, such as covered patios.

How is an air cooler different from a standard fan?

Standard fans circulate air around a room. Though the airflow could feel refreshing on a hot day, the air temperature itself remains unchanged. In contrast, evaporative air coolers use the natural process of evaporation to decrease the temperature of warm air, resulting in longer-lasting cool air.

How is an air cooler different from a mist fan?

Mist fans simultaneously blow out air while spraying a fine mist of water droplets. In very hot and dry climates, these water droplets evaporate, but in most cases, the watery mist sinks to a puddle on the ground.  Mist fans are mainly for outdoor use, unless you desire your fan giving you a surprise shower inside your living room.
Like mist fans, evaporative air coolers also employ the physical law of evaporation, except the process takes place internally, within the unit. The air exiting the unit contains water vapor and not water droplets. This makes air coolers suitable for indoor rooms as well as the outdoors.

How is an air cooler different from an air conditioner?

Air conditioners artificially cool down hot air through powerful compressors and chemical refrigerant. While they can tackle the most hot and humid environments, they are more expensive and require much more power to operate. Additionally, window or portable air conditioning units must be connected to the outdoors to release the extracted heat. Evaporative air coolers are more limited in their cooling capacity but are substantially more environmentally-friendly and are easier to position where you need it.

Are air coolers energy efficient?

Yes. Air coolers do not contain complex machinery, so they consume very little energy. For example, most air cooler models consume from as low as 32 watts to 300 watts at their highest fan speed, depending on the size and CFM of the unit. At low speeds, some models consume as low as 7.4 watts.

By how many degrees will an air cooler decrease air temperature?

Air coolers operate by fanning warm air through a wet irrigation pad and blowing out cooler, more moist air. Because it’s such a natural process, the efficacy of an air cooler is highly dependent on the heat and humidity of its environment. The drier the climate is – with a relative humidity of not more than 60% - and the hotter the climate is, the greater the cooling action. In ideal conditions, in highly hot and arid climates, evaporative cooling can drop temperatures by 15°F. In more typical conditions, you can expect a moderate drop in temperatures, enough to take off the edge of acute heat.

Will air coolers increase humidity?

Evaporative air coolers fan out a cooler, moister breeze that will steadily increase the humidity of your space. However, air coolers also thrive on an intake of fresh, dry air. This means, for it to work correctly, you should ensure there is sufficient cross-ventilation, by keeping windows and/or doors open, to release excess humidity and allow for a circulation of fresh, dry air.

Are air coolers effective in humid environments?

Air coolers are most effective in dry regions with humidity levels under 60%. In humid climates, air coolers can still be beneficial when used in their fan-only mode or operated during less humid days. Portable air conditioners are recommended for indoor cooling in more humid cities (check out the full range here). For outdoor use, evaporative coolers are one of the few cooling options that reduce temperature and can be used even in more humid climates.

Are air coolers only beneficial during the summer season?

Not necessarily. However, some evaporative air cooler models are 3-in-1 appliances that adapt into humidifiers for the drier winter season. Used on a low-fan setting, they can add moisture to dryness caused by central heating or simply by a harsh winter climate.

Operation

What is the typical operation routine for an evaporative air cooler?

All evaporative air coolers require water and a power source to operate. Some evaporative air coolers are designed with removeable tanks that can be filled with water; others have fixed tanks; while others have a continuous water connection that can be connected directly to a garden hose or another water source.  Once filled with water, plug the unit into an electric outlet, and play.  Some coolers include an ice tank that can be loaded with ice cubes, which chills down the circulating water and creates a refreshingly crisp breeze. Many models will include other functional details, like oscillating louvers, remote control, LCD panel, varying fan speeds, timer and more.

How large of an area will it cool?

The cooler’s CFM is the key indicator of its cooling capacity. A cooler with a CFM of 200 for example, is a spot cooler, and can affect a radius of about 50 sq. ft. A cooler with a CFM of 2000 can cool a space that is about 500 sq. ft. Bear in mind, though, that evaporative air cooling is also highly dependent on the heat and humidity of its environment for appreciable cooling.

How heavy are air coolers?

Air coolers are relatively light, however that weight increases significantly once the unit is filled with water. Most air coolers are constructed with caster wheels and convenient handles to ease mobility.

How loud are air coolers?

Most indoor air coolers max at 60 dBA on their highest fan speed setting – which is the sound level of conversational speech in a quiet room. Smaller spot coolers operating on low speed offer almost whisper quiet sound for use during the night.

Can I use an air cooler in a room without a window?

Evaporative air cooling works by drawing in hot, dry air, and fanning out cooler, more moist air. After a while, though, your room will need ventilation or a cross-breeze to circulate the more humid air out the room and restart the process with fresh dry air. It is recommended to keep a window and/or door open for adequate cross ventilation. In large rooms, it doesn’t necessarily need air from outdoors, but it does need some type of airflow to keep the cooling action moving, so keeping doors open to other areas will be needed.

How can I improve the performance of my air cooler?

Understanding the mechanics of the cooler will help you improve its performance. Evaporative air cooling works by drawing in hot dry air, and fanning out cooler, more moist air. After a while, though, your room will need ventilation or a cross-breeze to circulate the more humid air out the room and restart the process with fresh dry air. In a very large room, it doesn’t necessarily need air from outdoors, but it does need some type of airflow to keep the cooling action moving. Therefore, confirm there is adequate cross-ventilation.


Another performance booster is running cooler water through the air cooler. You can boost the coolness by adding ice into a dedicated ice compartment (if the model is equipped with this) or directly into the water tank – but only if the ice does not hinder the pump or its circulation.

My cooler is not cooling down my space. Why?

Run through this troubleshooting checklist:  

  • My climate’s humidity is less than 60%.
  • The cooler’s CFM is appropriate for the space it is in.
  • The water flowing through the unit is cold.
  • There is adequate cross-ventilation.

My tap water is hard. Is that OK to use?

Yes. We suggest regular maintenance, draining and refilling the water tank with fresh water each week, as well as cleaning your unit and honeycomb media to avoid calcium deposits (see the User Manual for instructions on how to clean the Honeycomb media). To help clean the system, you can  add a small amount of vinegar to the water tank and run the air cooler in evaporative cooling mode for 15 to 30 minutes, then, drain the tank of the vinegar water and refill with fresh, clean water and run the evaporative cooling mode for another 30 to 15 minutes. This will help to break down the calcium deposits.

Can I put a freezer pack inside the ice compartment?

Using a freezer pack in the ice compartment should work well – only if it’s not impairing the water circulation.

Can I use an air cooler in my garage?

A garage is very suitable for evaporative cooling. Its open ventilation can assist with the airflow the air cooler needs. Additionally, if your floor plan allows for it, you could roll in a large capacity outdoor air cooler model, equipped with hose connection, for continuous, hassle-free cooling.

Can I use an air cooler in my vehicle?

Evaporative air coolers do not require significant electric usage and can hook up to a standard 115V outlet. However, evaporative air coolers should not be used in your vehicle while it is in motion, in case the water inside the unit destabilizes and causes electrical shock or injury. You could attach the air cooler to the vehicle’s electric supply while the car is stationary. Ensure the windows are open for cross-ventilation and to avoid dangerous over-heating.

Can I use an air cooler on my camping trip?

You can hook up your air cooler to a 15V, 1.3A, 50W power supply in your RV or tent. We suggest choosing an outdoor model that is constructed to withstand rain, direct sunlight and other adverse weather conditions.

Can I use an air cooler while running central air or central heat?

An evaporative air cooler can reduce the need to solely rely on costly central air to cool down your home. The air cooler can assist in circulating central air throughout the room, as well as boosting the air conditioner’s cooling action. Less air conditioning translates into more cost-savings. The air cooler will also help by adding moisture to air that is over-dried by air conditioning. During the winter, air coolers can also be set to a low fan speed to act as a humidifier, alleviating the drying effects of central heat by adding humidity to the air.

Maintenance

What is the typical maintenance routine for an evaporative air cooler?

For best routine maintenance, after each use of the cooler in evaporative cooling mode, switch to fan mode for 15 minutes before switching the unit off. This will ensure the honeycomb cooling media dries quickly and does not become a breeding ground for mold or mildew.


To prevent mineral deposits, drain and replace the water in the water tank weekly. Wipe down the water tank with a clean cloth. Remove any debris from the water filter sponge (if included), rinse and replace. Every two months or sooner (depending on your weather, water and usage conditions), visually check the carbon dust filter (if included) and the honeycomb cooling media. Rinse in running water and remove any debris with a soft toothbrush. WARNING: Disconnect the power outlet before cleaning the unit.

My cooler arrived with a distinct odor. How to rid it?

The honeycomb media is chemically treated to ensure longevity but may have some odor when first used. The odor will reduce after a couple uses and dissipate with time.

How often should I change the honeycomb cooling media?

Every 3-6 months, depending on your usage and maintenance.  Check the honeycomb visually, clean it with water and a soft toothbrush. If dirt cannot be removed, or if the fibers are starting to deteriorate, then it’s time for a new pad. Honeycomb cooling media replacements are available for purchase by various online retailers including Sylvane.com and Amazon.com. Remember to purchase the right sized honeycomb for your unit by searching for the model number of your evaporative cooler. If you need assistance or cannot find your model’s replacement accessory, please contact our customer support at usinfo@jmatek.com or call 1-800-474-2147.

How to prevent mildew and bacteria?

To avoid mildew or bacteria, you can add a small amount of vinegar to the water tank. Alternatively, you can purchase a specialized bacteriostatic water treatment – easily available online. Also, be sure to follow best maintenance practices, by letting the cooler run on fan-only mode for 15 minutes after using evaporative cooling, to dry out the honeycomb pad and prevent mildew.