Efficiency of electric appliances and conserving power

In many instances, the same purpose can be achieved using various different 

appliances. In order to get illumination we can use filament bulbs, fluorescent 

light tubes or CFL lights (compact fluorescent lights). Choosing a more efficient 

appliance helps us to save energy. A few different types of bulbs giving the same 

illumination, their power output and life times are given in Table

According to Table, it is advantageous to use LED bulbs as light sources. 

However, the use of good quality LED bulbs is limited due to their high initial cost.

Similarly, the efficiencies of cookers used to prepare food are different from one to 

another due to varying amounts of heat wastage. Old cookers that use heating coils 

are the lowest in efficiency. Emersion heater is highly efficient for heating water. 

The reason is that, all the heat generated in the heater is transferred to water when 

using it. Heaters which contains hot plates such as rice cooker is more efficient 

because heat loss is less from them. Although microwave ovens cannot be used 

to cook all types of food, they are very efficient since they produce heat inside the 

food items. In addition to these, induction cookers with high efficiencies are now 

available in the market. In these devices, the variable magnetic field emitted by the 

cooker generates heat only at the bottom of the cooking utensil.

For Extra Knowledge:

The power consumption of television sets that use LCD screens is lower than that 

of the old televisions that use cathode ray tubes. LCD television sets that use LED 

lights to illuminate the screen have a very low power consumption and are known 

as LED televisions in the market. 

Similarly, it is more efficient to use table fans to cool houses than ceiling fans. 

Using the most efficient device suitable for a particular purpose whenever possible 

would help to minimize the future energy crisis.

If 40% of the energy supplied to a certain electric appliance is lost as heat, then 

only 60% of the energy would be used for the expected purpose. This means that 

the efficiency of the electric appliance is 60%. We should try to minimize the loss 

of electric energy as heat and get the maximum out of the electric energy supplied 

for a particular purpose. Ironing all clothes required for a week in one occasion is 

more efficient because it saves electricity used in the initial heating of the iron. All 

the unwanted lights of the home should be switched off. Also, you have to use more 

efficient bulbs such as CFL and LED bulbs.