By 2012 we won't be able to even purchase incandescent light bulbs. So, switching to CFLs or LEDs won't be a matter of choice, but of mandate. Maybe, you'll feel better about the switch if you know just how much electricity and dollars it may end up saving you.
In my small 3bed/2bath home with basement and two car garage, I counted 24 lights (that included the individual lights over the mirrors in the bathrooms). That number also includes the ceiling lights which have two or three sockets each for a grand total of 36 bulbs. According to EnergyStar.gov, each CFL bulb I use, could equate to a to savings over the life of the bulb. To reach my own savings, I used the following data: cost per type of bulb, wattage per bulb, total number of bulbs, kilowatt hours used(KWh), and cost per KWh to calculate my total energy consumption and related costs. To determine my cost per KWh, here in Georgia, I used the average cost per KWh of 10.19 cents. (Source Energy Information Administration: Nov 2009)
Incandescent Bulbs To calculate how much electricity I was consuming using incadenscents I used this formula:
watts used per bulb per day* the number of bulbs*365 days = the total wattage 60 watts *36 bulbs* 365 = 788400 total watts per year.
To calculate my energy costs:
watts/watts per KWh*my cost per KWh 788400/1000 *.1019 = .33. That's the total cost of electricity for all my lights
To calculate the total cost I needed to add in the cost of the bulbs. I assumed that each bulb would last 1 year at an hour per day.
Cost of one bulb * the number of bulbs.84 per bulb * 36 bulbs = .12
So the total cost for all my lights: .33 + .12 = 0.57
CLF Bulbs Assuming I switch all my lights to CFLs, I used the same formulas The CFL bulbs I currently have use 14 watts per bulb and give me the same type of ambient light that a 60 watt bulb would. The cost of these bulbs was 7.97 for a 4 pack of bulbs. (Home Depot) So each bulb cost me .00 (rounded up from 1.9925) Most companies guarantee CFL bulbs for 5-6 years, so the cost breaks down even further to.40 per year per bulb. (.00 divided by the useful life of 5 years.)
Energy usage:
14 watts * 36 bulbs * 365 days = 183,960 total watts
Electricity Costs:
183,960/1000 *.1019 = .75 total cost of electricity
Total cost of bulbs per year
$.40 * 36 = .40
Total costs:
.75 + .40= .15
LED Lights LED lights are expensive, by my standards. They range in price from .95 (on sale) to .95. The best regular priced light I found was 39.95, but the most common price for an LED light that gave off a soft white light was .95. That's the price I used to calculate the costs for using LED lights. The good news for these lights is that they last for 20 years and only use 7.5 watts. So, if I spent .95 for one bulb, that would make my yearly cost to be .50 (rounded up from .4975).
Energy Usage
7.5 watts * 36 bulbs* 365 days = 98,550 total watts
Cost of energy
98,550/1000 *.1019 = .04
Total cost of bulbs:
.50 * 36 bulbs = .00
Total costs
.04 + .00 = 6.04
This analysis clearly shows that incandescent bulbs are the most expensive overall. CFLs come out as the most cost effective. However, there are drawbacks to the CFL as they require special handling for recycling due to the mercury content (small though it may be). While we should all be concerned about saving energy and money, we don't know yet what impact the mercury content in CFLs will have on landfills and other waste management systems. We attempted to clean up mercury in the air and in our ground water back in the 70s by regulating the amount of mercury emissions manufacturing and power plants could release, and mecury contamination is still a problem. Let's be careful not to make it an even more serious contamination problem. If you're going to use CFLs, please, recycle properly.
LED light bulbs, while more expensive than CFL's, use far less energy. They contain no toxic material, and the plastic contained in them can be made from other recycled plastic, and they can be recycled into other plastic items. While the LED lights appeal to my overall philosophy, if I went out and purchased 36 LED bulbs, my initial investment would be ,798. I don't know about you, but that's way out of my budget!
There are some lights in my home that are on most of the day. I work out of the house, so the lights in the basement office are on all day and into the evening. Currently, they are all CFLs. I'm considering switching to LEDs for these lights and any others that are on most of the day. The bulbs will last for 20 years and only use a fraction of the power of any other type of bulb.
We have already seen the price of CFLs drop considerably over the past few years. The laws of supply and demand will, hopefully, also drive the price of LED lights down to a more affordable investment. I'll be watching the prices.
If you want to see how much you too can save, just plug your numbers into the formulas above. Enjoy!
