It's that time of year when all air conditioners whirr like life depends on them. Well, it does, doesn't it?

We take a look at how these essential gadgets work and what you can do to make them work better.

Looking inside

The machine is divided into three parts - compressor, evaporator and condenser. When we switch on the A/C, the coolant rushes into the compressor where it is compressed and reaches the hot coils of the evaporator to change into hot gas. This hot gas passes into the condenser where chilled coils transform the gas into a very cool, low-pressure liquid again. Hot air from the room is blown out through vents. Air from outside mixes with the coolant liquid and is blown back into the room.

Hot air that is present in the room is lighter than cool air and so rises up to make place for the cool air from the A/C vents. This cycle continues till the room achieves its optimal temperature. Once that happens, the thermostat switches off the compressor and the fan keeps circulating the air until the air gets warmer and the whole process of cooling begins again.

The excess moisture that is sucked out of the room gets condensed to water in the condensing unit and is splashed back into the room through a special unit that makes the cooling more efficient. The unit also has a filter which blocks all kinds of dust particles, mould, pollen and allergens from getting inside.

Now, let's look at why the gadget shuts down, or worse, spews warm air back into the room?

There are many factors that can either slow down an A/C's cooling action or overwork its compressor, which in turn sucks up more electricity in addition to obstructing proper cooling.

Sajid Riaz, general manager, product development division, Super General Company, provides tips on how best to optimise the use of air conditioners during summer.

Weighing up the options

To begin with, an air conditioner has a limitation in terms of the area it can cool based on the strength of its compressor. A one-tonne air conditioner can cool about one-and-a-half square metres of area; a two-tonne machine will cool about three square metres and so on. If your room requires a two-tonne capacity A/C for optimal functioning and you buy a one-and-a-half tonne A/C because it is cheaper, you will not get the comfort you are looking for, apart from the fact the A/C will have to work harder and therefore push up your electricity bills.

An air conditioner works on a thermostat. "Mechanical thermostats in an A/C act like a room thermometer and have a mercury switch and thermometer coil. When the temperature in the room reaches the level you have calibrated on the thermostat, the mercury switch switches the circuit off. Modern digital thermostats use a resistor and a micro controller. The resistor has an electrical resistance and a micro controller measures the resistance and converts it into a temperature reading. When you calibrate the thermostat to a set temperature reading, as soon as the resistance reaches that level, the circuit switches off.

"Digital thermostats are a great help in energy conservation as they can be programmed to switch on and off several times during the day. The internationally accepted norm for a comfortable temperature is 24˚C. So you need to set your A/C at that notch. Once you switch it on, the compressor kicks in. It begins, let's say at 30˚C and since it has a smaller capacity, it has to work continuously to reduce the temperature from 30 to 24˚C so as to cool the area of the room. Usually when it reaches the optimal temperature, the thermostat stops the compressor from working and the A/C works on the fan mode. However, when the room is larger and the tonnage falls short, the compressor continues to suck in more energy to keep the temperature at that level steady. That's what leads to more electricity consumption.

"The money you saved in buying a lower capacity air conditioner gets spent on the next two months' electricity bills. In effect, you end up paying higher amounts. However, if you buy the required tonnage for the area that needs to be cooled, your compressor works smoothly, cooling is effective and energy consumption is on the lower side."

Help the gadget feel cool

In the case of a window A/C, putting an awning over it to protect it from the direct heat of the sun and the elements can increase its output and efficiency substantially. But ensure the awning is a little away from the A/C unit so as to not obstruct the free circulation of air. Having plants in the vicinity can keep the area cooler so the compressor has to work less hard.

If you live in an independent villa or housing unit, painting the exterior of your home in lighter colours will help reflect the heat and keep thearea cooler.

Inside, it is always advisable to have thick curtains to block out the sunlight and keep the room cool. If your windows are not curtained and the sunlight streams in, it takes longer for the room to cool.

For people who like to air their rooms, early morning is a good time to throw open the doors and windows and ventilate the room. Ensure the A/C is switched off during this time.

Do not try and overload your A/C by trying to make it cool more than it can. Keep the door of the room being cooled shut. If you try to cool the passages around the room, you will actually end up bringing in more humidity to the room in addition to burdening the compressor, which will now have to work harder to reduce the humidity.

Don't be left high and dry

Keep a humidifier in the room. Usually air conditioners also work as dehumidifiers, sucking out the moisture. Lack of moisture causes dryness of the skin, eyes and nostrils and leads to respiratory complications like wheezing, colds, coughing and other allergies. If you feel your A/C is causing the air to become too dry, a humidifier will help in restoring the moisture content in the room.

 

Healthy breathing techniques

One of the most important features in your A/C is the filter. Filters get clogged with dirt and other atmospheric debris and need to be washed at least once every 15 days to once a month, depending on the level of dust that has collected, to facilitate the proper and clean circulation of air. The air conditioner also needs periodical servicing and the filters should be replaced every year. Refrigerant coolant levels also need to be checked and topped up if low. This will not only reduce electricity consumption, but ensure that dirt and bacteria circulating in your home are minimal. So, stay switched on and enjoy the season.

Tips to make you AC work more efficiently

  • Do not turn your central air conditioner off during the day if the temperature is too high. Turning it off lets warmth and moisture build up in the house andit has to work twice as hard to cool the house when you switch it on only at night, resulting in higher electricity bills.
     
  •  Service your air-conditioning unit annually and also change filters periodically to ensure efficiency.
     
  •  Try not to cook too much indoors during blistering heat as the central A/Cs are not able to cool efficiently with that much heat in the house. Limit cooking to one dish, make more salads, order take-out meals or grill outdoors if the weather permits.
     
  • Turn off unnecessary lights to keep the home cooler.
     
  • Seal all holes that may allow air to pass through them.
     
  • Conditioned air loses some of its coolness as it travels from your air conditioner to your rooms. n Try to insulate all the seams and openings in your ducts by sealing them with aluminium tape.
     
  • If you live in a villa, install an attic fan as all the hot air in the house settles at the top and can be sucked out from ventilators there.
     
  • In a villa, if your roof needs replacing, you can opt for a lighter coloured roof to reflect the sun's heat.
     
  • If your air-conditioning system is 15 years old it is time to look for a replacement.