Matching replacement light bulbs to existing fixtures can be tricky, especially with older fixtures. Using new fixtures made for new lightbulbs gives you the greatest energy savings, reliability, and longevity compared with simply replacing bulbs.

Before replacing a light bulb and/or light fixture, it's a good idea to first understand basic lighting principles and terms. This understanding will help you make the most economical purchase.

Replacing Light Bulbs and Fixtures

You can replace older cfl and incandescent light bulbs with more energy-efficient options, such as LEDs.  Beyond lower efficiency, many incandescent bulbs are mismatched to their use.  For example, when used in recessed fixtures, A-type and reflector light bulbs waste energy because their light gets trapped in the fixture.  Also, some outdoor fixtures tend to disperse much of their light beyond the intended area, which causes light pollution.  This can be corrected by using bulbs with lower wattage or bulbs made for outdoor use.  

Replacing light bulb
Replacing inefficienct light bulbs with LED bulbs can save you a lot in lighting costs.

Fluorescent Lightbulb Disposal

All fluorescent lights contain small amounts of mercury. Some compact fluorescent lamps (CFLs) with magnetic ballasts contain small amounts of short-lived radioactive material. Because of these hazardous materials, you should not toss burned-out lamps into the trash.

Find out if there is a recycling program for them in your community--they are becoming more common, and some retailers will recycle CFLs for free. You can also dispose of the bulbs with other household hazardous wastes such as batteries, solvents, and paints at your community's designated drop-off point or during a designated day when you can put such materials with your curb-side trash pickup. See the EPA recommendations for cleanup and disposal steps.