In general

We would recommend that you replace incandescent (tungsten) bulbs with compact fluorescent units (CFLs). Compact fluorescent lights use about a fifth of the energy of their tungsten filament counterparts, and can last up to ten times as long. However, they are readily available in mainstream outlets and so only special applications are listed here (e.g. units which mimic natural light particularly well).

Likewise, if you are installing or replacing fluorescent tubes, T8 or T5 units are preferable to T12s. T8s are so widely available that outlets are not listed here, but we do list fittings and T5s.

LEDs (light emitting diodes) can be configured to achieve a similarly high efficiency to CFLs, and can be expected to last even longer. They are also more durable in sub-zero temperatures. They have reached the mainstream market for flashlights, bicycle lights, etc, but it is more difficult to find LEDs which substitute for less energy-efficient types in house lighting.

In this section, we list sources for the following:

• Compact fluorescent lights : special applications only
• Light fittings specifically designed for CFLs
• T5 fluorescent tubes
• Light fittings for T5 and T8 fluorescent tubes , including ballasts, specular reflectors, etc.
• LED lighting with an efficacy of at least 40 lumens per watt (The lumen per watt is the standard unit used to measure the ratio of light out to power consumed.)
• Energy-efficient outdoor lighting which also carries the International Dark Sky Association (IDA) Seal of Approval. Such units avoid causing light pollution by proper shielding above the light.
• Places where you can recycle dead compact fluorescents. As these tubes contain small quantities of mercury, it is best not to send them to landfill.