Evaporative Coolers: How They Work and How to Choose One

A properly cooled home is such a luxury during the summer months, and if you live in a particularly hot climate, it’s an essential, allowing you to live and work in comfort. While the traditional method of cooling was to use an air conditioner, many people are now looking for alternatives, especially in hot, dry climates. That’s why you may have noticed increased popularity of evaporative air conditioning in Perth and Western Australia. Less expensive to install than air conditioning, and generally cheaper to run, evaporative coolers are a more environmentally friendly option, and might be suitable for your home. Here are some reasons to consider installing this type of system.

How do evaporative coolers work?

When you dive into a cold pool on a hot summer’s day, then get out, you’ll notice a chill on your wet skin. This is the same sort of process involved in evaporative cooling systems, which create a light mist throughout your home, which then cools as it dries. Effective in dry, hot climates such as Australia, it can therefore be more efficient than traditional air conditioning, which takes moisture from the air as it refrigerates, using a lot of energy.

Adding moisture to the air by using an evaporative cooler makes the cooling process much more efficient. Heat is needed to evaporate water, meaning the heat inside the house works to evaporate the mist from swamp cooler pads, therefore making the air feel cooler. Air moves over the pads pushing cooler air inside, while also bringing warm air out the home.

Because evaporate coolers use a mist of water, they allow you to keep your doors and windows at least part-way open for ventilation, giving you fresh air and a cool feeling breeze even on the hottest days of the year.

How much does an evaporative cooler cost?

Evaporative coolers, also known as swamp coolers, cost about half as much as traditional air conditioning. The exact price will depend on the size of your home, as well as the model you choose. When choosing an evaporative cooler, look for the CFM – cubic feet per minute of air delivered to the house. This will usually be in the range of 3000 to 25000, and depending on your climate, it’ll need to deliver 20 to 40 air changes per hour.

How does installation work?

There are two ways that evaporative coolers can be installed:

  • Air distributes to the centre of the home – if you have a small, open plan layout, then it makes sense for the cool air to be blown to one point
  • Ductwork distributes the air to individual room – in larger houses, the cool air can be delivered via ducts, ideal for houses that have a more closed plan and lots of rooms

Another option is to have smaller, individual coolers with a horizontal flow, which can be installed onto windows. They’re popular in areas where temperatures are moderate, but may not be sufficient for hot climates such as Western Australia. There are also portable units available that can be moved from room to room, but these don’t create much of a cooling effect unless your home is already humid.

In areas where daytime temperatures regularly exceed 35°C, then it can be worth investing in two-stage evaporative coolers. These systems are more expensive, but use less humidity and have more efficient motors. Therefore, they can be worth the extra expense if you’ll be using it a lot.

How do you use an evaporative cooler?

Most evaporative coolers are very easy to use, and have two or more speeds to allow you to adjust it to your comfort. Before you switch it on, you should open windows and vents on the side of your home that’s down-wind, and experiment to see how far open they should be. If not opened far enough, humidity can build up, while windows open too far can let the heat inside. If you don’t like leaving windows open, then ducts can be installed, which act as a sort of exhaust.

If you’d like to use your system as a fan during the milder months, then choose a model with a vent-only setting, which doesn’t humidify the air, but has the effect of a fan, so there’s a pleasant breeze through your home. If any family members have allergies, then you can also consider adding filters to your system.

How much maintenance is needed?

Evaporative coolers are very low maintenance compared to air conditioning, and an annual service is an excellent way to ensure it is operating at full capacity. You should also:

  • Regularly drain and clean your cooler according to system instructions
  • Remove any build-ups of sediment
  • Replace the pads twice or more during summer, depending on how often it’s used
  • Ensure the system is serviced before summer
  • Check the pads, filters, and other essential parts once a month

Clean cooler pads, as per manufacturer’s instructions, as well as filters

Do evaporative coolers have any downsides?

As with any cooling system, yes, there are a couple of downsides to evaporative coolers. They don’t always feel as cold as air conditioning, although they’re much cheaper and so can be run for longer periods. They’re also unsuitable for climates where there’s already a lot of humidity. If the system is installed on the roof, then it can be less effective, but nowadays most evaporative coolers are installed on the ground floor.

Evaporative coolers are becoming a popular alternative to air conditioning, especially in areas such as Perth where the summers can be unbearable dry and hot. A more natural way to cool your home, they avoid the unpleasant dryness associated with air conditioning, and the air isn’t recirculated, making it healthier around the home. If you’re considering installing an evaporative cooler, then it’s important to get the professionals to add the system to ensure it is sited properly, and that you get maximum cooling effect. Once it’s in your home, there’s no need to dread the long summer days, and you can enjoy a cool, fresh-feeling breeze in every room.