The most important and effective energy-saving and money-saving thing you can do in your home or office is to replace incandescent light bulbs with compact fluorescent light bulbs.
Incandescent bulbs are basically little heaters that also produce light. They make light by passing electricity through a small wire (filament). The wire heats up and glows, producing light. Unfortunately only 10% of the energy they use produces light; the other 90% produces heat. This is a very serious waste of energy.
Compact fluorescent (CF) bulbs pass electricity through a gas-charged tube. The chemical reaction produces the light. The bulb remains cooler and produces more light (measured in lumens) than incandescent bulbs, with less power. The average CF bulb uses 66-75% less electricity to produce the same amount of light as an incandescent bulb.
When you use less energy for your lighting, you save money. You save money because you use less electricity. Using less electricity means you’re ultimately using fewer fossil fuels, such as the oil, gas or coal used in power plants. You’re helping conserve those fossil fuels, and you’re helping to prevent the air pollution they produce when burned.
It has been estimated that if every U.S. household replaced just one 60-watt incandescent light bulb with a CF bulb, the pollution reduction would be equivalent to removing one million cars from the road. Think how it would be if we all replaced all of our bulbs.
Coming Up: Keep your eyes out for LED (Light-Emitting Diode) light bulbs. They’re not yet at the low-cost stage of CF bulbs, but they will be. And they offer far greater energy efficiency and longevity.
Advantages of CF bulbs Long Lasting - While CF bulbs cost more than incandescent, they can last anywhere from 8,000 to 15,000 hours, compared to the typical 1,000 for an incandescent bulb.
Money Saving – If you replace a 100-watt incandescent bulb with a 32-watt CF bulb (which provides the same amount of light), you can save at least $32 over the life of the bulb. Replace 10 bulbs in your home, and that’s a savings of more than $300. A bulb can pay for itself with normal use in just five months. Cool – CF bulbs are also cool to the touch, with a temperature of less than 100º F.
Rebates - Many utility companies offer rebates or even free bulbs to homeowners. Check to see if your local company has these offers.
Selection of shades – CF bulbs are available in several shades of light, ranging from bluish to golden or bright sunlight. Pick the ones best suited for your purposes.
For inside and outside — CF bulbs are designed for either indoor and outdoor use. Check the package to make sure you get the kind you need.
Hint Remember “Watt Four”—CF bulbs use about ¼ of the wattage as incandescent bulbs to produce the same amount of light (lumens). So as a rule of thumb, replace an old incandescent bulb with a CF bulb of about ¼ the wattage, i.e. replace a 60-watt with a 15-watt.
Plastic bottle light bulbs
Here's a basically free method of lighting rooms during daylight hours. Although designed originally for third-world residents with metal roofs, the principle is universal.