The Watt equals one joule per second. For example, if a 60W lamp remains on for one hour, the power consumed is 60 watts-hour. This would be the same amount of energy that would make a 120-watt bulb shine for half an hour. To get an idea of how much Watt represents, here are some reference values of the power of some household appliances: stereo, 200 watts; vacuum cleaner, 1000 watts; computer, 400 watts; exhaust fan, 300 watts; electric oven, 5000 watts; hair dryer, 1300 watts; LCD television, 150 watts. The name of this power unit is a tribute to the British engineer James Watt, for the recognition of the many researches that he made, to better understand the energy, as well as, the way in which he created machines that obtained a better use of it.
The Kilowatt is a power unit, equivalent to 1000 watts. If we express watt in units used in electricity, we can say that a watt is the electric energy produced by a potential difference of 1 volt and an electric current of 1 amp. This may seem too technical, but it is especially important not to confuse kilowatt (kW) with kilowatt-hour (kWh). This is because, the first is a unit of power, while the second is a unit of energy measurement. Power is usually a constant value within a given circuit. For example, the power of an air conditioner could be 1200 watts, or 1.2 kilowatts. As for consumption, this same air conditioner, if it was on for 10 hours would consume a total of 12 kWh. To know the value of this, just look at your electricity bill, to see how much your energy provider charges you for kWh.