The three primary consumer light‑bulb technologies are incandescent, compact fluorescent (CFL), and light‑emitting diode (LED). Incandescent bulbs use a heated tungsten filament in a sealed envelope, provide high color rendering and instant on but low luminous efficacy and short life. CFLs use a gas discharge and phosphor coating to convert UV to visible light, offering greater efficiency but limited dimming and mercury disposal concerns. LEDs use semiconductor junctions for high efficacy, long life, and directional control; more details follow.
Key Takeaways
- Incandescent bulbs produce light by heating a tungsten filament, offering warm color and dimming but low efficiency (~8–19 lm/W).
- Compact fluorescent lamps (CFLs) excite mercury vapor and use phosphor coatings, giving higher efficacy and longer life than incandescents.
- Light‑emitting diode (LED) bulbs convert electricity in semiconductor junctions, providing high efficacy, long life, and directional control.
- Choose by priorities: warmth and dimming (incandescent), cost‑effective retrofit (CFL), or efficiency and longevity (LED).
- Consider fixtures, dimmer compatibility, color temperature, and disposal (CFL mercury) when selecting a bulb type.
Incandescent Bulbs
Incandescent bulbs employ a tungsten filament sealed within a glass envelope that emits light when an electric current heats the filament to incandescence.
The lamp family includes standard A‑shape and smaller specialty forms; variants use vacuum or inert gas fills and halogen augmentation to reduce filament degradation.
Filament geometry and glass mountings determine mechanical support and thermal paths; ANSI C78.20‑2022 specifies dimensional and electrical requirements.
Thermal emission from the filament defines spectral output (~2700K) and luminous efficacy (≈8–19 lm/W), which increases with wattage. The filament typically operates at temperatures over 2,000°C, producing most energy as heat rather than visible light. Most electrical energy becomes heat so only a small fraction is emitted as visible light.
Base types provide standardized electrical contacts and mechanical retention across voltages and fixtures.
Advantages include Ra≈100, instant on and dimmability; disadvantages are low energy efficiency and short operational life relative to modern solid‑state and fluorescent alternatives.
Many households historically used ~1,000‑hour incandescent lamps as a standard lighting option.
CFL (Compact Fluorescent Lamp) Bulbs
Following the description of filament‑based lamps, compact fluorescent lamps (CFLs) present an alternative that replaces thermal emission with gas‑discharge fluorescence: an electrical current excites mercury vapor in a folded glass tube, generating ultraviolet radiation that the inner phosphor converts to visible light.
CFLs employ a ballast (magnetic or electronic) to regulate discharge and are configured for retrofit via Edison screw or pin bases.
Typical units deliver ~4× the efficacy of incandescents, e.g., 13 W ≈ 60 W, with ~10,000‑hour life and stable lumen maintenance.
Common geometries include spiral, tubular and reflector forms.
Limitations include warm‑up time, limited dimmer compatibility, and small UV emission.
End‑of‑life handling requires attention to mercury disposal and to phosphor composition due to potential toxic constituents.
Some LED retrofit options can directly replace CFLs in G24 sockets after ballast bypass or removal, offering longer life and higher efficacy with ballast bypass sometimes required.
LED (Light-Emitting Diode) Bulbs
LED (light-emitting diode) bulbs convert electrical energy into visible light via semiconductor p–n junctions, offering high luminous efficacy, directional emission, and long service life compared with thermal- and gas-discharge sources.
LED bulbs use semiconductor p–n junctions to efficiently produce directional, long-lasting light with high luminous efficacy.
They are available in multiple form factors (A19, BR30, PAR30/38, MR16, T8) and specialized types (filament styles, capsule, reflector, decorative), enabling varied beam angles and application-specific photometry.
Color temperatures span warm to cool white and are selectable for task or accent lighting.
Driver compatibility and retrofit bases affect installation and electrical performance; quality drivers regulate current, minimize flicker, and determine dimming compatibility.
COB, SMD, and DIP technologies yield different lumen densities and thermal management demands.
- Retrofit Bases compatibility considerations
- Beam Angles and directional control
- Filament Styles and aesthetic options
They also work exceptionally well in layered lighting schemes when paired with concealed strips and diffused panels to produce balanced ambient, task, and accent illumination with reduced glare and preserved color rendering through high-CRI strips.
