kilowatt vs kilowatt-hour?

Question

What is the difference between a kw consumption and a kilowatt-hour consumption and how would one use these terms?
On an appliance will stand 2kw and yet energy consultants speak of consumption in kw-hours. Very confusing. Please help.

Answer 1

A lot of good answers here... I might offer my perspective as well to see if it sticks.

kW = kiloWatt which is a unit of POWER.
Power is the rate at which energy is used per unit time (an indicator of how fast an item uses energy). The kW can also be representated as kJ/s (kilo-Joules per second) where the Joule is a standard unit of energy.


kW-hr = kiloWatt-hour which is a unit of ENERGY
The kiloWatt-hour is a convenient unit of energy to use rather than the kilo-Joule (the kilo-Joule is a pretty small unit of energy compared to the amount of energy a household requires). It represents the power used by the appliance multiplied by the hours in use. 1 kW-hr = 3600 kJ

So as you can see, the two units are fundamentally different. Appliances show their power ratings (kW) on the nameplate to give you an idea of how much energy is used per second by the item. A consultant, on the other hand, would use the kW-hr to indicate how much energy a home or business uses and maybe recommend ways to reduce the amount of energy consumed.

Answer 2

Kilowatt Vs Kilowatt Hour

Answer 3

A Watt is a unit of power (energy per unit time), defined as a Joule per second. So a kilowatt is a kilojoule per second.

The kilowatt-hour is kilowatts times hours, so is a unit of energy. I think it's a ridiculous unit, because we already have the kilojoule (essentially, a "kilowatt-second"), but that's life.

Answer 4

This Site Might Help You.

RE:
kilowatt vs kilowatt-hour?
What is the difference between a kw consumption and a kilowatt-hour consumption and how would one use these terms?
On an appliance will stand 2kw and yet energy consultants speak of consumption in kw-hours. Very confusing. Please help.

Answer 5

If your house has say ten 100 watt light bulbs, that totals 1,000 watts or one kilowatt. If you leave these lights off the power company will not charge you one cent. However, if you turn all the bulbs on and leave them on for one hour, you have actually consumed power; actually one kilowatt-hour of power and you will be charged about 10 cents.

The power meter on your house does not know the total watts of all your electric appliances but it can sense when you are drawing current through them. The meter is calibrated to show total kilowatt-hours of electric consumption between meter readings. Hope that helps a little.

Answer 6

The kilowatt-hour (symbolized kWh) is a unit of energy equivalent to one kilowatt (1 kW) of power expended for one hour (1 h) of time. The kilowatt-hour is not a standard unit in any formal system, but it is commonly used in electrical applications.

An energy expenditure of 1 kWh represents 3,600,000 joules (3.600 x 106 J).

The consumption of electrical energy by homes and small businesses is usually measured in kilowatt-hours.

The kilowatt-hour is rarely used to express energy in any form other than electrical. A quantity of gasoline, oil, or coal contains potential energy that is liberated when the fuel is burned. The heat energy resulting from combustion of such fuels is usually expressed in joules according to the International System of Units (SI) or in British thermal units (Btus) according to the foot-pound-second (fps) or English system. If this energy is used to operate an electric generator, the output of the generator over a certain period of time can be expressed in kilowatt-hours.

Answer 7

Kilowatt-hours is important when it comes to calculating peak energy use. This is not a real problem for households, but for business, particularly industrial or manufacturing businesses it is critical. Think of it this way, if all the businesses in an industrial park turn on all their equipment at once, this places a sharp spike in the demand on the system. If a business can gradually start-up operations over a period of time, there is less spike. Less spike in demand requires less infrastructure to support. Reduced infrastructure means less cost to the energy supplier.

The business might consume the the same amount of energy (same kilowatts) over a period of time, but the kilowatt-hours at peak demand might be significantly less.

Why kW-hours and not joule's? Its all in the calculation by the energy supplier using kW and hours of demand. Joule's is not relevant to them. Its a nice engineering unit, but doesn't really reflect what they want to discuss.

Answer 8

kilowatt is the rate of power consumption. kilowatt x hrs is the accumulated power or the total energy consumed.

Kw = Power
Kwh = energy

Answer 9

KW is power. KWH is energy.

The only difference is that power is energy per unit time. The only reason the "energy consultants" talk about KWH is because that is what the power compaines use on your electricity bill and they are too stupid to know otherwise.

Answer 10

x= y-6=t5-5