Energy Efficient Lighting

What difference does it make if you use a compact fluorescent bulb instead of an incandescent one?

For every kilowatt of electricity that is generated from a fossil-fuel based power source like coal, oil or natural gas; 154 pounds of carbon dioxide are released into the atmosphere.

Carbon emissions cause greenhouse gases cause global warming.

So it makes sense to use fewer kilowatts. If you use 60, 75, or 100-watt incandescent bulbs daily for four hours or more, replace them with 17, 20, or 23-watt compact fluorescents. A 20W fluorescent lamp offers the same light as a 75W incandescent lamp, saving 55 watts.

Some well known facts about CFLs

• CFLs use one quarter of the energy that similar incandescents use
• CFLs last 8 to 10 times longer than incandescents
• CFLs used daily will pay for themselves in one to two years

Shop for compact fluorescent bulbs and get a 10% discount by using the source code CET10 during checkout.

The technical details

In incandescent lamps, an electric current heats up a metal filament in the bulb, making it glow white-hot and give off light. The problem is that only 10% of the electricity is used to make light - the rest ends up as heat.

Compact fluorescent bulbs are simply much more efficient at turning electricity into light. A typical compact fluorescent is a one-piece light that holds both the fluorescent tube and the electronic ballast that controls the electric current. They are designed to screw easily into a standard incandescent fixture without modification. They can be used outdoors as long as they are protected from the weather, so they are suitable for use in barns and storage sheds.

Special considerations

• In very cold weather there is a slight delay before they reach full brightness
• CFLs are more expensive (about $5 to $7 per bulb), but if in use for more than 6 hours per day, they will pay for themselves within about two years
• CFLs contain a tiny amount of mercury and therefore should be handled and disposed of properly. Learn more from this MassSAVE pdf.

The environmental benefits of making the change are considerable

Using just one 15W CFL eliminates* the need for one of these:

• 350-400 pounds of coal
• almost one barrel of oil
• 600-800 pounds of carbon dioxide emissions that cause greenhouse gases

*savings is based on the full lifecyle of the CFL

Using one 20W CFL 5 hours per day, 365 days per year:

• Prevents more than 154 pounds of carbon emissions per year

Replacing a 75-watt incandescent light with a 20-watt compact fluorescent:

• Saves about 550 KwH over its lifetime. If that electricity comes from a coal-fired generating plant, the savings represents about 1300 pounds of carbon dioxide and 20 pounds of sulfur dioxide that would have otherwise been released into the atmosphere

If the fluorescent tubes in your barns and work areas are more than 12 years old, there’s a good chance that they’re due for an upgrade to modern T8 fluorescent lamps. T8 lamps are the highest efficiency lamps for 4 and 8-foot fixtures, and can provide the same amount of illumination using 20 to 40 percent fewer watts. An electronic ballast with the T8 lamp saves an additional 7 to 10 percent.

Larger incandescent fixtures, such as pole lights or floodlights should be replaced with more efficient lights such as sodium or metal halide lamps. These are designed specifically to cast a big pool of light over a wide area but with significantly less energy consumption. These lights, which require unique fixtures, are typically seen in streetlights, modern warehouses, and large stores.

Your electric company may provide incentives for efficient lighting. CET staff will help you with the process as needed. The Energy and Small Farm Sustainability project is funded by the Northeast Sustainable Agriculture Research and Education Program.