Let’s try to understand how the electricity bill for the house is calculated and see how turning off house lights can help reducing it.

Have you ever had a quick look at your electricity bill? You will notice that you are charged in kilowatt-hours. But what exactly does that mean?

A watt is a common unit of electrical energy. If a watt is a measure of electrical energy, what exactly is energy?

Energy is a measure of the instantaneous electricity that is used when any electrical device is running. Many of us have noticed the labeling on every device, from light bulbs to microwave ovens, showing power requirements expressed in watts.

A kilo means a thousand, so a kilowatt equals 1,000 watts. However, both watts and kilowatts are only a glimpse of instant electrical use of power, which is what we really care about. As for what the General Electricity Company will charge you for, it is the accumulated amount of energy that has been used during a certain period of time. Power is expressed in kilowatt-hours.

Here is an analogy that may help simplify the concept. Imagine you are driving a car at a certain speed. When you look at the speedometer, it is the equivalent of energy or average energy consumption.

But you know that looking at the speedometer doesn’t tell you anything about how far you’ve traveled. So you have to look at your speed over the time you’ve been driving. Energy equals distance in the driving time.

In order to understand how much energy you used, you have to know the time that passed and you were consuming a certain amount of energy. Energy is power over a period of time.

If the energy consumed in small quantities, the energy is measured in watts / hour. But if the consumption is for the family, then the amount of energy consumed increases and therefore the measurement is done in thousands of watts / hour, or kilowatts / hour.

Let’s illustrate this with some examples. A kilowatt-hour of 1000 watts is used in one hour. If you turn on 10 light bulbs of 100 watts each for one hour, you will use 1 kWh of energy. Or if you forget to turn off one 100-watt bulb for 10 hours, it will also consume 1 kilowatt-hour of electricity.

Let’s take this last example a step further, if you leave the light on and don’t turn it off

Every day at work or school, you would be consuming 260 kilowatt hours per year. Assuming at 25 cents per kilowatt hour, leaving that one light on for each working day would cost you \$65 per year.

If you know this information in advance, you will definitely make sure to turn off all the house lights before leaving the house.

Therefore, it is recommended to use economical LED bulbs with low wattage.

Now you know. That kilowatt-hour is a measure of energy, which is power over time. The electric company calculates the energy or electricity it consumes in kilowatt-hours 