The need of the hour is an AC, but if that’s something that doesn’t fit in your budget, don’t sweat it out (literally). Go for the next best thing – an air cooler.

They might not give you a wintertime chill like an air conditioner but they’re one-fourth the price of ACs and are easy on the electricity bill too. Here’s what you need to know when investing in a good air cooler.

How they work

Air coolers are box-like units that consist of a fan, water-soaked pads and a pump. To use the cooler, you have to fill it with appropriate amounts of water. When you switch it on, the hot air from the surrounding is circulated in the cooler and sent through the water-cooled pads. This lowers the temperature of the air by quite a few degrees before this cool air is blown out into the room.

Types of air coolers

There are two kinds of coolers, a desert cooler and a room cooler. While they both work in the same way, evaporation of water that helps cool the surroundings, there are a few features that set them apart.

1. The desert cooler is usually fitted outside a window and takes in the air from outside. The fan in this unit is used as an exhaust. It usually provides better cooling. However, it also requires more space, water and power.

2. The room cooler on the other hand is less powerful than a desert cooler. This cooler is kept inside the room and is placed on a trolley that can be moved around. The fan in this cooler is used to force the air out.

3. If you’re really looking for a cooling unit to help combat serious heat, the desert cooler is ideal. However if the room is small and the temperature is not too scorching, a room cooler will suffice.

Based on how they function, there are three kinds of coolers- direct evaporative coolers, indirect evaporative coolers and two-stage evaporative coolers.

a. The direct evaporative ones are the most widely used coolers. They lower the temperature of the air by the use of latent heat of evaporation which changes water to vapour.

b. The indirect evaporative one operate by using some form of a heat exchanger. The cooled moist air doesn’t come in contact with the outside environment.

c. Two stage coolers as the name suggests, go through two stages when cooling. First, the air is precooled by a heat exchanger and this precooled air then goes through the water soaked pads. This particular type of cooler helps lessen humidity.

air coolers

Size matters

Air coolers come in various sizes to fit the requirements of your room. They are rated by air delivery or the cubic feet per minute of air (CFM) that they can blow out in the room. Here’s a simple formula to calculate your requirements.

Multiply the area of the room in square feet with the ceiling height and divide that number by two. This will give you the CFM of the airflow needed.

(Room size in sq ft X ceiling height / 2 = CFM of airflow

Example: If the room is 500 sq ft and the ceiling height is 8 ft, then

500 X 8 / 2 = 2000 CFM

That means, you will need a cooler with a minimum air flow of 2000 CFM

Read the air delivery details that come with the air cooler before you buy one.

Features

Air cooler come with a variety of features but here are some of the important ones that can be of great benefit to you.

Cooling pads

The cooling pads used in most air coolers these days are the honeycomb ones as they are designed to provide maximum cooling, low-pressure drop and longevity.  It is essential to check for pad thickness too. Ideally, it should be at least 90 mm thick in order to cool the air well.

Electronic Thermostats

Coolers with electronic thermostats can vary the fan speed and also switch off and on the pump and fan automatically.

Water level controller

Air cooler with automatic water level controllers can maintain water in the unit at pre-set levels. The automatic controller allows or prevents the water from the connection to flow into the cooler tank. This prevents flooding of excess water.

Water level indicator

The indicator on the water tank helps you determine how much water is in the tank. This saves you the effort of opening and closing the cooler to check for the water.

Automatic shutoff dampers

These shutoff dampeners are flaps that open when the fan starts and shuts when the fan is put off. Having this feature covers the cooler when it’s not in use thus reducing the loss of cooling from the cooler.

Adjustable speed

Coolers with variable speed allow you regulate the speed as per your liking and helps you control the temperature in case it gets a little too cold.

Castors

Movable air coolers come with castors at the bottom which help you move the cooler around freely. This makes it easy when you want to drag it across rooms.

Remote control

All the latest air coolers come with remote controls that make things easy and convenient when customising the modes.

Timer

Some air coolers also come with a timer, where you can set a sleep time on the unit. This is particularly helpful if you don’t want to keep the cooler switched on all night.

Cover Image Courtesy: Shutterstock.com; Image via newtechnology.co.in

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