LED VS INCANDESCENT
Electronic vs Heated Filament — LED lights produce light using semiconductor technology, while incandescent lights produce light by heating a tungsten filament until it glows. LED technology generally reduces energy consumption and routine lamp replacement, while incandescent relies on a simpler filament-based source. Regardless of technology, the complete AGL fixture must meet the required photometric, colour, electrical, and operational requirements.
At a Glance
| Feature | LED | Incandescent |
|---|---|---|
| Light-generation method | Semiconductor | Heated tungsten filament |
| Energy efficiency | Generally higher | Generally lower |
| Power consumption | Usually lower | Usually higher |
| Heat generation | Lower, but requires thermal management | Very high |
| Operating life | Generally longer | Generally shorter |
| Start-up | Instant | Instant |
| Failure mode | Gradual degradation and/or electronic failure | Often sudden filament failure |
| Light-source replacement | Usually less frequent | More frequent |
| Electronics required | Usually yes | Usually no for basic operation |
| Optical design | LED + secondary optics | Filament + reflector/lens |
| Maintenance | Generally lower | Generally higher |
How Each Light Source Works
LED
An LED produces light through electroluminescence in a semiconductor. Electrical power passes through electronics/a driver into the semiconductor, which converts it directly into light.
Incandescent
An incandescent lamp produces light by passing electrical current through a tungsten filament, heating it until it emits both heat and visible light.
Electronic Conversion vs Heated Filament
Easy memory: LED converts electrical energy to light electronically. Incandescent creates light by heating a filament.
Where the Input Energy Goes
An incandescent lamp converts a significant proportion of its input energy into heat rather than light. An LED generally produces more useful light for the same electrical input.
LEDs still generate heat and require proper thermal management — the efficiency gain reduces heat loss, it doesn't eliminate it.
How Each Source Ages
LED
LED performance may gradually decrease over a long operating life, with light output depreciating slowly over time.
Incandescent
Incandescent lamps commonly fail when the filament ages and breaks, typically resulting in a sudden loss of light.
Failure Behaviour Compared
| Characteristic | LED | Incandescent |
|---|---|---|
| Gradual light-output reduction | Common over service life | Can occur |
| Sudden light-source failure | Possible | Common |
| Electronic failure | Possible | Generally not applicable to the basic lamp |
| Filament failure | No | Primary failure mode |
| Replacement frequency | Generally lower | Generally higher |
Shaping the Beam
LED AGL Fixture
The LED source is paired with secondary optics to shape the light into a controlled beam directly at the source.
Incandescent AGL Fixture
The filament source relies on a reflector and lens/optics assembly to shape and direct the light into a controlled beam.
The final AGL beam depends on the complete optical system, not only on the light source itself.
Native Emission Pattern
An LED can naturally emit light over a more limited directional range than a traditional filament source. An incandescent filament, by contrast, radiates light more broadly in most directions.
The final beam of an AGL fixture is determined by its complete reflector, lens, and optical design — not by the source's native emission pattern alone.
Typical Maintenance Activities
LED
- Cleaning lenses
- Checking electrical connections
- Monitoring light output
- Inspecting thermal components
- Replacing modules or fixtures when necessary
Incandescent
- Cleaning optical components
- Replacing failed lamps
- Checking lamp connections
- Inspecting reflectors and lenses
Series-Circuit Compatibility
LED Fixture
May contain electronics that condition the available electrical supply for the LEDs.
Incandescent Fixture
A basic filament lamp may operate more directly from its designed electrical supply, without conditioning electronics.
LED retrofits can require additional consideration of electrical compatibility, operating current, power characteristics, CCR compatibility, isolation-transformer compatibility, and monitoring-system compatibility.
Thermal Behaviour
Incandescent
The filament reaches a very high temperature, producing both visible light and significant heat as a direct part of its operating principle.
LED
Produces light plus heat that must be managed through a heat sink or thermal path. LED fixtures generally operate with lower overall energy consumption, but excessive temperature can reduce light output, service life, reliability, and colour stability.
Technology Doesn't Guarantee Compliance
Both LED and incandescent fixtures must ultimately satisfy the applicable optical requirements — photometry (intensity, distribution, beam spread) and colorimetry (colour characteristics).
LED technology does not automatically guarantee better photometric compliance than incandescent technology. The complete fixture must be tested and evaluated according to the applicable requirements.
Full Engineering Parameters
| Parameter | LED | Incandescent |
|---|---|---|
| Energy efficiency | Generally higher | Lower |
| Power demand | Generally lower | Higher |
| Service life | Generally longer | Shorter |
| Heat generation | Lower but significant thermal management required | High |
| Lamp replacement | Less frequent | More frequent |
| Failure mode | Electronic failure or gradual depreciation | Filament failure |
| Electronics | Usually required | Minimal/basic |
| Optical control | LED + optics | Reflector/lens |
| Maintenance demand | Generally lower | Generally higher |
| Initial complexity | Higher | Lower |
LED vs Incandescent vs Halogen
It is useful to distinguish these three light-source technologies rather than treat halogen and incandescent as unrelated:
A halogen lamp is a type of incandescent lamp. It uses a tungsten filament like a conventional incandescent lamp, but operates with a halogen gas system that modifies the lamp's behaviour and helps support higher filament temperatures and improved performance compared with traditional incandescent designs.
LED vs Incandescent
LED and incandescent are fundamentally different ways of producing light. One is an electronic semiconductor process, the other is a heated-filament process.
LED is a semiconductor light source with higher efficiency, longer life, and electronic/thermal management requirements. Incandescent is a heated-filament light source with simple operation, high heat generation, and shorter filament life. Regardless of technology, the complete AGL fixture must meet the required photometric, colour, electrical, and operational requirements.
For AGL retrofits: check CCR, isolation-transformer, and monitoring-system compatibility alongside photometric performance before treating an LED swap as a simple lamp replacement.
Engineering & Expert Notes
Check Electrical Compatibility
CompatibilityLED loads behave differently from filaments.
Look at Heat and Mounting
ThermalVerify thermal design.
Measure Output After Change
VerificationConfirm intensity and colour.
Update Spares and Records
RecordsKeep registers current.
Frequently Asked Questions
LED → electronic, energy-efficient, long-life light source. Incandescent → heated filament, simple but energy-intensive and shorter-life source.
A halogen lamp is a type of incandescent lamp — it uses a tungsten filament, but with a halogen gas system that supports higher filament temperatures and improved performance over a traditional incandescent design.
No. LED technology does not automatically guarantee better photometric compliance than incandescent technology — the complete fixture must be tested and evaluated against the applicable requirements.
No. LEDs generate significantly less heat than incandescent filaments, but they still produce heat that must be managed through a heat sink or thermal path — excessive temperature can reduce output, life, reliability, and colour stability.
Yes, natively — an incandescent filament radiates more broadly, while an LED emits over a more limited directional range. However, the final AGL beam is shaped by the complete reflector, lens, and optical design, not the source's native pattern alone.
Electrical compatibility, operating current, power characteristics, CCR compatibility, isolation-transformer compatibility, and monitoring-system compatibility, in addition to photometric performance.
Governing Documents
For an actual project design, always verify the current edition of the applicable documents.
FAA AC 150/5345-46
Specification for Runway, Taxiway, Heliport, and Vertiport Light Fixtures — covers LED and legacy filament-source fixture requirements for airport lighting.
ICAO Annex 14, Volume I
Aerodrome Design and Operations — photometric and colour requirements applicable regardless of light-source technology.
CCR & Series-Circuit Documentation
Manufacturer and project-specific documentation on CCR and isolating transformer compatibility with the fixture technology selected.
Final Engineering Note
Do not select a fixture technology on efficiency claims alone. Confirm measured photometric and colorimetric performance and full system-level electrical compatibility.
LED is not automatically superior to incandescent — both must meet the same photometric, colorimetric, electrical, and mechanical requirements to be compliant AGL fixtures.
Compare the Systems. Then Learn How to Engineer Them.
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