Air Coolers Buying Guide

Posted by Alex Wells on

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 vapour.

Image of a stylish living room with a grey sofa and a copper frame glass coffee table, with a black air cooler.

How Does An Evaporative Air Cooler Work?

As mentioned earlier, 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 vapour.

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 vapour 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.

Informative diagram of how an air cooler works.

The Advantages of Evaporative Air Coolers

  • Low energy consumption - Air coolers consume much less energy than air conditioners which in turn means that the running costs are much lower.
  • Eco friendly - 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 - Air coolers cost much less than air conditioners to purchase and maintain which means they are a great investment.
  • Portable – Air coolers are of a convenient size to place in any room or area that needs cooling.
  • Circulate fresh air - 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.

The Disadvantages of Evaporative Air Coolers

  • 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 – 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 – Air coolers are not particularly quiet units and are not the right choice if quiet cooling is needed.

How to Choose the Right Air Cooler For You

When you are choosing an Air Cooler there are some key considerations you should take into account so that you select the best Air Cooler for you.

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

    2. Water Tank: The Water tank capacity determines how often you'll need to empty the 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.

    3. Fan Speed: An 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 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.

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

    5. Design & Portability: If you plan on moving your Cooler around, its best you go for a portable Air Cooler. This type of 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 Air Coolers should be able to do between 20 - 55 Air Changes. Each 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.

    6. 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.

The Difference between an Air Conditioner and an Air Cooler

An Air Conditioner does also lower the ambient temperature of a room like an Evaporative Air Cooler but requires significant energy to do so. They require the use of a chemical refrigerant gas to condense hot air and maintain the cooling by expelling that hot air outdoors via a hose. Evaporative Coolers also come with a variable thermostat and the unit will work to cool down to your set temperature. Evaporative air coolers are suitable for outdoor use where Air Conditioning units work best in enclosed environments.

Whereas, an Evaporative Air Cooler does not require any chemical gas or a hose hanging outside of a window to expel hot air. Evaporative Air Coolers operate via a simple electrical plug and then they are ready to use.

This means that Evaporative Air Coolers use a fraction of the power that an air conditioner.

How to Use an Evaporative Air Cooler?

There are three variables which are essential for getting the most out of an Evaporative Air Cooler:

Humidity - or rather, the lack of humidity is the most critical element of evaporative cooling. The drier the air, the greater the amount of water vapour that will be evaporated into the outgoing air, and the greater the cooling power. An Evaporative Air Cooler works best in arid or semi-arid regions which have relative humidity below 60%. A humid climate will inhibit the evaporation process since the incoming air is already saturated with moisture.

Water Temperature - the colder the circulating water is in the unit, the colder the outgoing air is in the room. As mentioned earlier, many Evaporative Air Coolers will have an additional ice compartment so that ice can be added to make the water even colder.

Ventilation for an Evaporative Air Cooler to work, a fresh flow of air is required to come into the room via an open door or window. This is because if moist air is allowed to recirculate back into the unit, it’s efficacy will diminish.

Frequently Asked Questions

Q. Is an air cooler the same as an air conditioner?

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

Q. Is an air cooler the same as a fan?

A. 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.

Q. Are air coolers effective?

A. 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.

Q. Are air coolers noisy?

A. 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 Conditioner as the majority of the noise comes from the outdoor unit.

Q. Are air coolers energy efficient?

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

Q. Are air coolers good value for money?

A. 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.

Q. Are air coolers portable?

A. 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.

Q. Do air coolers require a hose out of the window?

A. 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.

Q. Can I put an air cooler in my bedroom?

A. 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.