These bulbs lock into GU24 light sockets with a twist. Brightness is measured in lumens; the higher the lumens, the brighter the bulb. Bulbs with a warm light appearance have yellow tones. Bulbs with a cool light appearance have white/blue tones and are good for inspecting. A bulb’s estimated yearly cost is based on 3 hours of usage per day at $0.11 per kWh.

CFL (compact fluorescent) bulbs are energy efficient, but take several seconds to reach full brightness. They contain small amounts of mercury (for disposal information, visit www.epa.gov/cfl).

Often used in recessed can fixtures and track lighting, these bulbs produce a focused beam of light. Brightness is measured in lumens; the higher the lumens, the brighter the bulb. Bulbs with a warm light appearance have yellow tones. Bulbs with a neutral light appearance are commonly used in workspaces. Bulbs with a cool light appearance have white/blue tones and are good for inspecting. A bulb’s estimated yearly energy cost is based on 3 hours of usage per day at $0.11 per kWh.

BR and R bulbs have wide beam angles that create broad beams of light. Their length makes them good for use in large can fixtures.

LED bulbs last longer and are more efficient than other technologies. They generate little heat and withstand vibration. Plastic LED bulbs are shatterproof.

Replace high-intensity discharge (HID) lights with the longer-lasting, energy-efficient LEDs. Brightness is measured in lumens; the higher the lumens, the brighter the bulb. LED lights are perceived as brighter at night than high-intensity discharge light technologies, so they require fewer lumens to provide the same brightness. Match your old light’s wattage to find the right LED bulb. A bulb’s estimated yearly cost is based on 3 hours of usage per day at $0.11 per kWh.

Ballast bypass bulbs eliminate the need for a ballast, so the socket must be wired directly to the power source.