kW and kWh Explained - Understand & Convert Between Power and Energy
The difference between kW and kWh, power and energy, which to use when, And these aren't the only units of energy - there's the BTU, the watt hour (Wh), the . What is the difference between Watt and Kilowatt-hour (kWh)?. Watt is the unit of power whereas kilowatt-hour (kWh) is the unit of energy. Watt. The difference is quite simple, but many people muddle them up. Watts (W). A watt (W) is a unit of measurement of power. Watts therefore refer to the power of.
Differences between Power (Watts) and Energy (Kilowatts-hour, kWh) | Tips and Tricks HQ
OK, but a lot of people don't really understand the difference between energy and power either So let's start at the beginning: Energy is a measure of how much fuel is contained within something, or used by something over a specific period of time. The kWh is a unit of energy. A physicist might throw their arms up in disgust at how we've over-simplified one of the fundamentals of the universe.
But fortunately we're not writing this for physicists The kilowatt hour kWh is a unit of energy The Calorie is a unit of energy And the joule J is a unit of energy And these aren't the only units of energy - there's the BTU, the watt hour Whthe therm, and plenty of obscure units that you're unlikely to have heard of.
It's a bit like how you can measure distance in units of feet, metres, miles, km and so on. The distance between New York and London is fixed, but you can express that distance as 3, miles, or 5, km, or 18, feet etc. When people talk about a particular biscuit containing Calories, they're talking about the amount of energy contained within that biscuit.
That's with " Calories" meaning kilocalories, which is the unit that is almost always meant when people talk about the "calories" in food. Energy can change form.
We could eat the biscuit to provide us with energy. Or we could burn the biscuit and turn it into heat energy. Given the right equipment we could turn the heat energy from the burning biscuit into electrical energy to run lights and fans and so on. Some energy would be wasted in the conversion process, but it should be possible to get that burning biscuit to run a light bulb for at least a few seconds.
Probably the best option would be to eat the biscuit, but hopefully you get the general idea - the biscuit contains energy that can be converted into different forms Electricity and other fuels supply energy in a form that we can use to run the equipment in our buildings.
Our biscuits contain a certain amount of energy - Calories or 0.
What do watt and kWh mean?
But biscuit energy is not in a form that we can easily use to run the equipment in our buildings However, we can easily make use of electricity.
And, provided we've got a gas or oil burner, we can easily make use of gas or oil. One form of energy comes through wires isn't electricity clever?! At the end of the day it's all just usable energy in different forms. We can express quantities of these forms of energy in terms of kWh.
We buy or generate the kWh of energy, and we use it to fuel the equipment in our buildings. The relationship between energy consumption kWh and time A typical building uses more energy over long periods of time than it does over short periods of time: On February 16th a building might have used 95 kWh.
Over the week starting April 12th it might have used kWh. From January 1st to December 31st it might have used 31, kWh. Given the three figures above, we can easily see that the building used more energy over the course of than it did on February 16th However, we can't immediately compare the efficiency of the building over each of those periods. If a kWh figure covers a day, we can only compare it fairly with other kWh figures that cover a day.
If a kWh figure covers a week, we can only fairly compare it with other kWh figures that cover a week. If we have the kWh from February and the kWh from March, we can't really compare the two figures fairly, because February is typically 28 days long, whilst March is 31 days long. This article explains more about the problems that arise if you compare the kWh used in one month with the kWh used in the next. Energy consumption expressed in terms of kWh doesn't often mean much unless you also know the length of the period that the kWh were measured over.
And it's difficult to make fair comparisons between kWh figures unless they are all from periods of exactly the same length. Figures expressed in terms of power e. Power is the rate at which energy is generated or used. The kW is a unit of power. Strictly speaking energy isn't actually generated or used, it's converted from one form into another. Like how the energy stored in oil is converted into heat when you burn it. And like how the electricity that runs a fan is converted into the motion of the fan blade kinetic energy.
But this is a distinction that people generally don't worry about when they're staring at an excessive energy bill and wondering how they can "use" less energy. So power is a measure of how fast something is generating or using energy. The higher a building's kW, the faster that building is using energy. Joules per second makes it obvious that power is the rate at which energy is being generated or used.
It's like how miles per hour makes it obvious that speed is the rate at which distance is being travelled. James Watt The watt W is another unit of power. It doesn't make it quite so obvious what power means. But the watt is actually just another name for Joules per second. Just some bright spark decided that equations and whatnot would be simpler if power had its own unit instead of being expressed using units of energy and time together. And they named this unit after James Watt, the Scottish inventor who had an important hand in the development of the steam engine.
The watt W is a measure of power And the kilowatt kW is a measure of power too one kW being watts. Things that "generate power" Items of equipment like boilers, electricity generators, and wind turbines, take energy in one form e. There's a limit to how much useful stuff these things can generate, and that is expressed as the rate at which they can generate energy. Which is, by definition, their power. Consider a 10 kW wind turbine Provided it has the optimum level of wind which probably doesn't happen nearly as often as its owner would likeit can generate 10 kW of power.
How long does it take to generate 10 kW? That's a question that would only be asked by somebody that didn't understand what power was.
It's a bit like asking "how long does it take to travel 10 miles per hour?
How to Convert Watts into Kilowatt Hours | Sciencing
The two are closely connected, but we'll get to that shortly. Things that "use power" Items of electrical equipment like light bulbs, computers, and fans, take energy in the form of electricity, and use it to do useful things for us. Really they're converting the energy into other forms heat, motion etc. The rate at which these things use energy is their power. Or, depending on the thing, and the person you're talking to, you might hear it called their "load" or their "demand", or you might just hear it referred to in terms of a W or kW value.
Light bulbs are a simple example: The watts aren't affected by how long the W light bulb is running for A second, an hour, a day - no difference - so long as it's switched on it will be using W of power. It is simply a unit of measurement that equals the amount of energy you would use if you kept a 1, watt appliance running for an hour: So if you switched on a watt light bulb, it would take 10 hours to rack up 1 kWh of energy.
Or a 2, watt appliance would use 1 kWh in just half an hour. While a 50 watt item could stay on for 20 hours before it used 1 kWh. What else takes around 1 kilowatt hour?
- The differences between Power (Watts) and Energy (Kilowatts-hour, kWh)
- kW and kWh Explained
- What is a kWh? kW and kWh explained
A kilowatt is simply 1, watts, which is a measure of power. So, for example, the 10, watt electric shower in the top bullet point above could also be called a 10 kilowatt shower. A kilowatt hour kWh is a measure of energy. So a 1, watt drill needs 1, watts 1 kW of power to make it work, and uses 1 kWh of energy in an hour.
How many kilowatt hours should I be using each year? That depends on the size of your home, the number of people in your family, and whether you spend a lot of time out at work, or most of your time at home.
According to energy industry figures: If you live alone in a small home and are out at work full time, you might use 2, kWh of electricity a year and 9, kWh of gas A small family who live in a three-bedroom house and are in full-time work and education might use 3, kWh of electricity and 13, kWh of gas Four or five students sitting around all day in a large four-bedroom house could rack up about 4, kWh of electricity and 19, kWh of gas Can I use kWh to compare energy costs?