Are evaporative air coolers as ‘cool’ as you think?

Updated 12 May 2019

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People see evaporative air coolers as a cheaper option when compared to air conditioners. / Photos by Fahim Siddiqi / White Star
People see evaporative air coolers as a cheaper option when compared to air conditioners. / Photos by Fahim Siddiqi / White Star

KARACHI: Every year during the summer months there is a rise in the sales of air conditioners. There is also a rise in sales of air coolers, which, as their name suggests, also give off cool air and are a far cheaper solution to beat the heat.

Unlike air conditioners, which are far more complicated with chiller pipes, gas, compressors, etc, air coolers, or evaporative air coolers, run the air through water to reduce the air temperature as the water evaporates. But they need water for that.

Some also add ice to the water being poured in to make them more effective. But the problem here is that they add to the humidity. That’s why they are also called desert coolers as they suit dry climates, which can always do with a little extra humidity. Thus they are not really recommended for humid areas.

Still, the fact that they are far cheaper than air conditioners has prompted people living in humid areas such as Karachi also to go for them. And these days they are doing so in a big way. The markets here have been flooded with several kinds of air coolers.

The disposable, drum-type room caller is said to last only one season. / Photos by Fahim Siddiqi / White Star
The disposable, drum-type room caller is said to last only one season. / Photos by Fahim Siddiqi / White Star

There is the normal kind with the regular plastic body, manufactured in Gujrat usually, which comes in a variety of sizes and is available for under Rs20,000. There is also the metal sheet body air cooler, popularly known as the ‘Lahori style’ cooler, that is now available here for something between Rs7,000 to Rs9,000 per unit. And now there is the new variation, the cheapest plastic drum air cooler, made out of the disposable blue plastic drums used for chemicals being introduced in the market.

The drum air cooler can be easily made at home too. People who have done so have uploaded videos on YouTube about how to make them. Although not everyone here is making it themselves, some local manufacturers are and they have been selling like hotcakes. “But they are all jugar [hack], that will be good only for one season,” says a dealer selling the better varieties and who sees the drum varieties, which he calls ‘bucket type’ as nothing more than nuisances.

The Lahori-style air coolers have a metal sheet body. / Photos by Fahim Siddiqi / White Star
The Lahori-style air coolers have a metal sheet body. / Photos by Fahim Siddiqi / White Star

Disadvantages

As mentioned earlier, air coolers are not suitable in humid areas as their use increases humidity. Though they do not use gas like air conditioners and are said to be rather eco-friendly, health experts say that the water poured in them to keep the padding moist can become stagnant giving way to fungus and infections.

“For example, if anyone in a room being cooled by an air cooler is suffering from any bacterial infection, that infection can spread through the air cooler to make everyone in the house sick,” a specialist of chest infections told Dawn.

The regular plastic body air cooler. / Photos by Fahim Siddiqi / White Star
The regular plastic body air cooler. / Photos by Fahim Siddiqi / White Star

“From the stagnant air it will go to the stagnant water in the cooler and then from there it will spread after passing though the padded lining already laden with fungus.”

Published in Dawn, May 12th, 2019