Electricity 101
January 2nd, 2013 by Jennifer Brown

How it works and how to save money

electricMost schoolchildren’s first introduction to electricity is the story of Ben Franklin and his kite experiment.

For many people, that introductory lesson in electricity is where the education stops. Unless it is a job requirement, you may feel there is not much need to understand how electricity reaches your home. You know that if you flip a switch, the lights come on. You plug in your cell phone, and it charges. If the lights don’t come on, you call the electric company.

While you may not need to fully understand the route electricity takes to get to your home, it makes sense to understand where power comes from, and how to get the most out of the service you receive.

The Basics

Electricity is the flow of electrical power or charge. It is considered a secondary energy source because it comes from the conversion of other sources of energy known as primary sources.

These primary sources include coal, natural gas, nuclear, hydroelectric and oil. Some energy sources—such as sunlight, wind and water—are renewable and can be replenished. Others—such as oil, natural gas and coal—are non-renewable and cannot be replenished.

Measuring Electricity

Electricity can be measured in three ways.

Volts (V): A unit of electric force that measures the pressure of electricity. House electricity is 120 volts. Flashlight batteries are 1.5 volts. Car batteries are 12 volts.
Watts (W): The measure of power that can be generated by an electric current. Most appliances and light bulbs are labeled with the wattages they use. Incandescent light bulbs are typically 60, 75 or 100 watts. Microwave ovens and hair dryers are 1,000 or 1,200 watts. A kilowatt (kW) is equivalent to 1,000 watts. A kilowatt-hour (kWh) is a measurement of energy consumption. It is the amount of power used over time, and the basis for how electric bills are calculated.
Amperes (amp): The measure of how much electricity is moving through a conductor. Amperes equal watts divided by volts. A typical household electrical outlet is 15 amps.

Phantom Power

There are many small ways to save energy, such as turning off the lights when you leave the room or running only full loads in your washing machine. A more encompassing way to save energy is to reduce phantom power.

Even when turned off, most electronics consume a small amount of electricity if they are still plugged in. Chargers for mobile devices consume electricity if they are plugged in, even when they are not actively charging the device.

This wasted energy, called “phantom load,” accounts for as much as 10 percent of a home’s total electric use.

Save money by unplugging your electronics when you are finished using them. Using a power strip can help you unplug multiple devices at once. “Smart” power strips automatically cut off phantom loads.

Light Bulbs

You can’t talk about saving energy without talking about light bulbs. But deciding what is right for your home can be confusing.

Newer light bulbs, such as compact fluorescent lamps and light-emitting diodes, last longer and use less energy than traditional incandescent bulbs.

CFLs can be as much as 75 percent more efficient than basic incandescent bulbs. LEDs can last up to 25 times longer than a classic incandescent bulb, but are more expensive.
Light bulb packaging now includes a lighting facts label, which includes such information as brightness, estimated yearly cost, life of the bulb, the light’s appearance from warm to cool and the wattage.

As we switch to more-efficient bulbs, we need to change the way we shop for them. In the past, we have selected light bulbs based on their wattage. But wattage indicates how much power is used rather than the brightness of the bulb. The term to learn is lumens.

Lumens measure brightness. For example, a traditional 60-watt incandescent bulb produces about 800 lumens of light. A CFL produces the same 800 lumens using less than 15 watts.

Despite the variety of choices, you can use lumens to compare the brightness of any bulb. Once you know the brightness you need, you can shop wisely and get the most for your money.

The Cost of Electricity

Use these formulas to calculate your energy use and projected costs.

Calculate Energy Consumption: Power x Time = Energy
For example, using a 100-watt bulb for 10 hours equals 1 kWh.
(100 watts x 10 hours = 1,000 watt-hours or 1 kilowatt-hour.)

Calculate Energy Costs:
Power (kW) x Time (hours of operation) x Price ($/kWh) = Cost of operation.

To find out how much it may cost to run a specific appliance, follow these five easy steps. You are billed per kWh, or for how much electricity you use in one hour. Examples are based on an average cost of $0.144 per kWh.

1) Obtain the wattage (watts) from the appliance nameplate. Example: A quartz heater with a nameplate of 1,500 watts.
Note: If listed as kW, skip to step 3. If amps are specified, multiply amps x voltage to obtain watts.

2) Divide the number of watts by 1,000 to get kW.
Example: 1,500 W ÷ 1,000 = 1.5k W.

3) To find out how many kWh the appliance uses, multiply the kW times the number of hours* the appliance runs each day.
Example: The heater runs for 10 hours per day = 1.5k W x 10 hours = 15 kWh per day.
* If the appliance operates for less than one full hour, divide the number of minutes by 60. For example: a hair dryer is used 5 minutes each day, or 5 ÷ 60 = 0.083 hours per day. A 1,250-watt hair dryer = 1.25kW x 0.083 hours per day = 0.1 kWh per day.

4) To calculate the daily operating cost, multiply the kWh of the appliance by the average cost per kWh.
Example: Quartz heater daily cost = 15 kWh x $0.144 = $2.16 per day.

5) To calculate the monthly operating cost, multiply the daily cost by the number of days the appliance is used during the month.
Example: If you run the 1,500-watt quartz heater 10 hours a day, 30 days a month = 15 kWh x $0.144 x 30 = $64.80.