First, let's review the three salient electrical properties we are looking at here. Volts which for the sake of this discussion is the available Voltage at a standard electrical outlet in the US which is 120 V. Amps is the amount of current, and Watts is the product of Volts and Amps (W = V x A).
|13W 800 Lumen CFL|
So let's start with an old-fashioned 100 W light bulb and assume that it is on in your living room for 6 hours a day. To calculate how many Watt hours (Wh) are used per day we simply multiply:
100 Watts X 6 hours = 600 WhWhich can be expressed as .6 kWh
Since we are billed by the month, we can multiply this by 30 to determine how many kilowatt hours per month we will be billed for:
.6kWh X 30days = 18kWh/monthTo determine our monthly cost for this lightbulb, we simply multiply by the electric rate, so let's assume the US average of $.10:
18kWh X $.10 = $1.80/monthThat doesn't look too bad does it? But if you run the math for an energy efficient compact fluorescent lamp you get the following:
13W X 6hrs = 78Wh
.078kWh X 30 days = 2.34kWh/month
2.34kWh X $.10 = $.23/monthSo by replacing that old style lamp with a compact fluorescent you would be saving $1.57 every month while also reducing fossil fuel emissions required to generate power for this electricity. If you do the math for a 10 W LED lamp it comes out at $.18 per month with a net savings of $1.62 every month. These lamps are so inexpensive now that you will recoup the investment within 5 months and since LED lamps last significantly longer than incandescent lamps it is a gift that keeps giving both to your wallet and to the planet. Also, LED lamps contain no mercury.
|9.99W 800 Lumen LED lamp|
|Recycling bins at Lowe's - next ro returns counter|
Newer appliances are often more efficient. For instance, it is generally assumed that if your refrigerator was made before 2000 that newer ones will be significantly more efficient. So you will not only be saving money, you will also be doing the planet a favor by reducing CO2 emissions from the fossil fuels used to generate electricity.