This is a simple but important concept to understand.
What is a kWh?
kWh stands for a kilo Watt hour. Which in essence means, the amount of energy generated/consumed over a time of 1 hour.
For example, if you have a 30 Watt light bulb on for an hour it consumes .03 kWh. That means each hour that light bulb is on it uses .03 kilo Watts of power.
If someone says their electronics in their house use 2kWh it means that each hour all their electronics require 2000 Watts.
The kWh is used for billing by utility companies and is the most likely form of energy statement you’ll see in your bills.
To calculate the cost of energy use the following formula:
{Wattage * hours used by appliance(s)} / 1000 * price per kWh = cost of electricity.
To calculate wattage:
Amps * Voltage = Wattage
The price of electricity varies. In Manitoba it’s around $.06/kWh while in California it can be as high at $.5/kWh. But generally it is around the low to mid ten cents. You can use that in your estimation when calculating your energy costs.
What is the difference between a Watt and a Watt hour?
A Watt is an instantaneous unit of energy. 100 Watt light bulb uses twice as much energy than a 50 W bulb.
A Watt hour is a figure of energy used over a period of time. 100 W bulb uses twice as much energy in a hour, than a 50 W bulb.
