Evaporative air coolers buying guide

Last updated: March 7, 2024

Evaporative air coolers, also known as "swamp coolers" allow more effective cooling than traditional fans without the cost of air conditioning units. Evaporative air coolers use evaporation to lower the ambient temperature to achieve a state of constant effective cooling. Evaporation is the chemical process of converting a liquid into a gas. In this case, the conversion of water into water vapor.

How does an evaporative air cooler work?

Evaporative air coolers use the process of evaporation to cool down hot air. To better understand this, remember a time when you have been extremely sweaty on a hot summer’s day. The humidity and mugginess are unbearable, until you stand in front of a fan where its breeze evaporates the heavy perspiration leaving your body cool and dry. This works because heat energy is lost during the chemical conversion of liquid into water vapor.

An evaporative air cooler works similarly. Most evaporative air coolers have three main components: a fan, a pump system to circulate water and a cooling pad that absorbs and retains water. The most popular and commonly used cooling pad is a honeycomb pad.

Water circulates through the air cooler and saturates the honeycomb pad. The fan draws the incoming warm air through the honeycomb cooling pad, where the evaporation process converts the water into water vapor and blows out cold air on the other side. The colder the water, the colder the air blown out. Some air coolers also have an additional ice component where ice cubes can be added to make the water even cooler. The effect of an air cooler can best be compared to the cool effect of a sea breeze.

The difference between an evaporative air cooler vs portable air conditioner

A portable air conditioner uses a refrigerant gas to lower the ambient temperature of a room. While an evaporative air cooler uses ice cold water to absorb unwanted heat and lower the ambient temperature of a room. A portable air conditioner can only operative effectively when it is used in a room with closed windows and closed doors while an evaporative air cooler can be used outdoors or with the windows and doors open.

It is important to note that a portable air conditioner is much more effective at cooling a room but it uses significantly more energy to cool a room compared to an evaporative air cooler. Portable air conditioners use the refrigerant gas to condense hot air and maintain the cooling by expelling that hot air outdoors via an exhaust hot air hose. Evaporative air coolers also come with a variable thermostat and the unit will work to cool down to your set temperature.

An evaporative air cooler does not require a refrigerant gas to cool the room temperatures or a hose hanging outside of a window to expel unwanted hot air. Evaporative air coolers are portable, easy to use, plug-and-play units typically used in shops, public spaces, patios, gyms etc. They are much cheaper than a portable air conditioner and they use up less energy to run.

Indoor and Outdoor use evaporative air cooler.jpg

Advantages of evaporative air coolers

Low energy consumption

Evaporative air coolers consume much less energy than air conditioners which in turn means that the running costs are much lower.

Eco friendly

Evaporative air coolers use water and do not use any refrigerant such as R410, R290, R32 etc for cooling as is the case for air conditioning units which means that air coolers are extremely environmentally friendly.

Affordable cost

Evaporative air coolers cost much less than air conditioners to purchase and maintain which means they are a great investment.

Portable

Evaporative air coolers are of a convenient size to place in any room or area that needs cooling.

Circulate fresh air

Evaporative air coolers use fresh air outside from an open door or window, cool it and then direct the new fresh cool air inside the room.

How to choose the right evaporative air cooler

Climate dependency

The main disadvantage of an air cooler is its dependency on the climate. In areas with high humidity, air coolers may prove to be less efficient at cooling air. This is because the air coming out of the cooler is humid due to the evaporated water. This in turn, means that the cooler adds to the humidity that is already in the air.

Water supply

Evaporative air coolers also need a supply of water, so when the water tank runs out of water, it must be refilled immediately if air cooling is to continue. If cooling is needed for a large space such as a warehouse, then it is important to look for an air cooler with a large water tank or the ability to top the water up directly.

Noisy

Evaporative air coolers are not particularly quiet units and are not the right choice if quiet cooling is needed.

Factors to consider when choosing an evaporative air cooler

When you are choosing an evaporative air cooler there are some key considerations you should take into account

Room size

You should make sure that the evaporative air cooler is suitable for your room size. Minimal power will mean the evaporative air cooler will not cool the room, and be only as effective as a basic fan. However, an evaporative air cooler which is too large has the risk of increasing the humidity level of the room. Our range of evaporative air cooler are suitable for room sizes between 4m² - 80m². We have options like the Honeywell, Master, Kool mini evaporative air cooler for your desk, all the way to large Honeywell 60 litre evaporative air cooler for warehouses and gyms.

Water tank

The water tank capacity determines how often you'll need to empty the evaporative air cooler, as the device must always have enough water for operation. The smaller the tank, the more often you'll need to top it up. It should also be easy to access the tank. Some built in tanks also have an ice compartment, which increases the machine's cooling performance. The tank should be able to hold water for at least 10 - 12 hours.

Fan speed

An evaporative air cooler will often have several fan speeds to meet your needs and to cool the room down at different rates. Check if it's possible to change the direction of the air flow, or if the evaporative air cooler has an oscillating mode. Breeze mode simulates natural air flow. Night time mode allows for quiet operation, which is a bonus while you sleep.

Noise level

You want to make sure you are comfortable with the noise level, as you will be using your evaporative air cooler regularly in your room. The noise level is measured in decibels (dB). If you are using your evaporative air cooler in the daytime, choose one with noise levels of up to 50 dB(A). If you want to use your evaporative air cooler overnight, keep the noise level around 40 dB(A).

Design & portability

If you plan on moving your evaporative air cooler around, its best you go for a portable evaporative air cooler. This type of evaporative air cooler will have castor wheels, making it easier to move it from one room to another. A carry handle will be helpful if you want to carry it up and down the stairs. You'll have to think about weight in this instance, as it is ideal to carry a lighter unit. The best evaporative air coolers should be able to do between 20 - 55 air changes. Each evaporative air cooler should be able to do 20 air changes an hour for optimum performance. Less than 20 air changes will mean the room will be too humid. However, more than 55 will increase the power consumption and running costs.

Cooling pads

A good cooling pad makes the difference in keeping your room cool for longer. Honeycomb cooling pads are efficient, with their long-lasting cooling. They can hold and absorb more water which leads to longer cooling.

How to clean, disinfect, and deodorize your evaporative air cooler

An evaporative air cooler is a powerful, efficient, and fantastic cooling solution in any hot, dry climate, but it is crucial to maintain your air cooler properly so you can enjoy its maximum benefits. One key reason to take care of your cooler is to prevent mold or a musty smell from developing. These problems are completely preventable and treatable, and there are some effective, hassle-free cleaning and deodorizing steps you can take to ensure your cooler stays in good working order.

The two parts of the cooler evaporative that require the most of your attention here are the honeycomb pads and the water tank, both of which need to be cleaned regularly. The cooler must be completely drained at least once a week, and the honeycomb cooling pads should be removed, washed, and air-dried at the same time. Note that product manuals may not always include the methods for cleaning these items.

It is important to replace the honeycomb pads with new ones at least once a year, but for regular maintenance it is advisable to clean them once a week.

The most thorough and safe way to clean the cooling pads is by combining water and vinegar in a 50-50 ratio solution. You can rinse or soak the pads in the solution, which will disinfect the pads and keep odor away.

Once the pads have been thoroughly washed, rinse them with water and allow them to dry completely before placing them back inside the cooler. Don't place the pads back in the cooler until the water tank is clean and ready to reassemble.

How to maintain your water tank

The water tank should be emptied and then wiped gently with a soft cloth and warm water to eliminate moldy residue that may have built up since the previous cleaning. You can also wash the tank with mild, soapy water and then flush it out with clean water.

Once the tank has been cleaned, the next step is to clean the pipes to ensure that they are free of mold. This can be successfully achieved by using the same 50-50 water and vinegar mix that was used to clean the cooling pads. The solution must run through the cooler for 30 seconds, which should be rinsed with clean water after you are done. Whether you use vinegar or soap to clean the tank, allow the cooler to run on fan mode on high speed for 10-15 minutes while the tank remains empty. This will ensure that the smell of vinegar doesn’t get absorbed into the honeycomb pads.

Once this is finished and you've already rinsed out the clean tank, fill it with clean water and allow the water to run through the tank for a couple of minutes to eliminate all the vinegar.

Deodorise your water tank

There are a few options for deodorizing your air cooler. According to this resourceful website, you could use any decent-brand floor cleaner disinfectant. One innovative woman has taken the tried-and-tested vinegar solution and mixed it with an essential oil of her choice. She says that by putting the new mixture in a handy spray bottle, the combination eliminates the musty smell from her cooler and leaves her house with a nice fragrance.

Here is her recipe, which is listed on her website:

Vinegar
10 drops of purify oil. This oil is known for eliminating odor and cleansing the air
15 drops of citrus bliss

It’s important to know that there are options to enhance your experience with evaporative room coolers, and knowing how to disinfect, clean, and deodorize them is a great start!

How many evaporative air coolers are required for your space?

Evaporative air coolers are rated according to the amount of airflow that they can generate. This is why they are actually grouped according to air flow per minute. The total quantity of air that a cooler unit can pump per unit time can be measured in either CFM (Cubic Feet Per Metre), CMM (Cubic Metres Per Minute), or CMH (Cubic Metres Per Hour).

The key to choosing your ideal evaporative cooler is choosing one with the right rating for your space. Therefore, you need to first calculate the CMH (m³/h) requirement of your cooler if you are seeking to know the right number of coolers to buy for your space.

Some important reference data on air exchange rate in different situation.

Air exchange rate is 20-30 times per hour for general environment.

Air exchange rate is 30-40 times per hour for crowed open area,

Air exchange rate is 40-50 times per hour for workshop with heating product equipments.

Air exchange rate is 50-60 times per hour for workshop with temperature with serious polluted air.

Remarks: air exchange rate can be in increased depends on outside temperature and humidity. Generally if humidity and temperature are high, air should be increased, in dry place air exchange rate can be decreased.

How many evaporative air cooler are required for your space?

To answer this question, simply use the formula shown below:

Numbers of air coolers required = Room volume x Air exchange rate/ Actual air flow volume of units (CMH).

For example:

Volume of the room = Length x Width x Height

Volume = 10m x 10m x 5m = 500m³

Lets say, the air exchange per hour in a general environment = 25 times

Therefore;

Total amount of air replaced per hour = 500m³ x 25 times = 12,500m³

Answer:

Then, You will choose an evaporative air cooler with a 12,500 CMH rating.

FAQs | Here are some frequently asked questions

Is an evaporative air cooler the same as a portable air conditioner?

An evaporative air cooler is NOT a fan or air conditioner.

Is an evaporative air cooler the same as a fan?

Traditional fans circulate air without affecting the temperature and making the room colder. The refreshing feel of a powerful fan is more due to the sensation on our skin rather than an actual change in the ambient temperature. An air cooler can lower the ambient temperature of a room by around 3°C – 6°C by throwing out cooler air.

Are evaporative air coolers effective?

Evaporative air coolers are effective if directed straight towards you giving a nice cool "sea breeze" effect. They are not as effective at cooling a room as an air conditioner would be.

Are evaporative air coolers noisy?

Evaporative air coolers are noisy units and are not recommended to cool a room that you may sleep in. A better alternative would be a DC Fan or a Wall Split air conditioning system as the majority of the noise comes from the outdoor unit.

Are evaporative air coolers energy efficient?

Evaporative air coolers use much less energy than air conditioners and they also do not use any refrigerant gas making them extremely environmentally friendly.

Are evaporative air coolers good value for money?

Evaporative air coolers sit in the ‘middle’ of the cooling range they are more expensive than a fan but cheaper than an air conditioner. Their effectiveness also reflects this as they are most effective at cooling whatever they are directly pointed at but are less effective at reducing the average ambient temperature of a room.

Are evaporative air coolers portable?

Evaporative air coolers come in a variety of sizes to accommodate all needs and most air coolers come with castor wheels so they can be easily transported from room to room.

Do evaporative air coolers require a hose out of the window?

Evaporative air coolers do not require a hose out of a window, but a common misconception is that they can be used in windowless rooms. In order to be effective, air coolers require a constant flow of fresh air to come into the room via an open door or window.

Can I put an evaporative air cooler in my bedroom?

Evaporative air coolers aren’t recommended for sleeping due to their high decibel output level. So, when a good night’s sleep is required, we recommend a DC motor fan or a Wall-Split air conditioner.

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