A few years ago, energy efficient light bulbs flooded the market and everyone jumped in line to buy them and save money. I wasn’t so sure though. It was clear that this ‘technology breakthrough’ cost more per bulb than the regular incandescent lights, so was there really savings to be had? I decided to make the purchase because I knew they would save energy, but how much money would I actually save?
Let’s Check the Costs
In order to see if we’re truly saving money with the energy efficient light bulbs vs. the incandescent bulbs, we need to find out what the average cost is for each. As expected the energy saving bulbs are fairly pricey at $2 a bulb, and the incandescent bulbs are less than half the cost at about 75 cents each.
How Long Does Each Bulb Last?
Alright, so as we expected, the energy saving bulb costs more than double, so now the question is, “How much longer will it last?” The old-school bulb will last only 1,000 hours and the new bulb will last ten times that amount at 10,000 hours!
Savings Per Year
The energy efficient bulb lasts 9,000 more hours than the traditional bulb, but what does this mean for our savings? How much does it cost to illuminate a light bulb for an hour? On average, electricity costs 12 cents per kilo-watt hour. By itself, that means absolutely nothing to me, so let’s find out how much it would costs to illuminate one light bulb for an entire year with this 12 cent/kWh cost.
One 60 watt light bulb might stay on for about 6 hours a day each day for the year. So, that’s 60x6x365, and it equals 131.4 kilo-watt hours. Multiply that by 12 cents and you’ll find out that your one light bulb is costing you about $16 per year.
The equivalent wattage of an energy efficient light bulb is 13 watts. Multiply that by 6 hours per day and 365 days per year and you’ll use up 28.5 kilo-watt hours, which will cost you about $3.50, which is saving you approximately $12 per year on that one bulb!
Savings Per Bulb
The above example shows you your savings per year, but I wonder what the overall savings is per bulb since the energy saving bulb lasts so much longer. The traditional bulb costs only 75 cents and lasts 1,000 hours. The energy saving bulb costs $2 and lasts 10,000 hours.
One traditional 60-watt will last 1,000 hours, which means it uses up 60 kilo-watt hours and costs $7.20. To match the length of the energy efficient bulb (10,000 hours), we’ll have to use 9 more, which will cost us a total of $72 in energy and $7.50 in bulbs. That’s a grand total cost of $79.50.
The energy efficient bulb will last 10,000 hours with 13 watts, which uses up 130 kilo-watt hours and costs $15.60. Add the cost of the bulb and you have a grand total of $17.60. Energy efficient bulbs will end up saving you over $60 per bulb!!! Who knew?
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I replaced all my light bulbs with CFLs. I saved a lot in electricity and they are still going strong 4 years later.
Energy is a measurement of power over some period of time. Power companies use the kilowatt hour because power use is cumulative; someone who uses an 11 watt CFL isn’t paying for the 11 watts that the bulb uses in any given instant, but rather how much power is used by that bulb over a month. To determine this cost, how many kilowatts a device uses is multiplied by how many hours it is used to get kWh, which are then multiplied by the price of electricity per kWh.
Great analysis, I have always known they were the lower cost option but never had any information to back that up other than what was on the box. Thanks for digging into this and sharing.
A few years ago, I replaced nearly all the bulbs in my house with CFLs. Unfortunately, I have not had a very good experience with them. Many of them burn out or go very dim after just a few months. It doesn’t seem to matter whether they are brand name or no-name bulbs. I’m hoping that the new LED bulbs will truly last a lot longer.