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How BulbFacts Tests

BulbFacts compares headlight bulbs in controlled housings with repeatable measurements, beam photos, output baselines, and notes that help explain real-world upgrade tradeoffs.

Lab methods
From unknown to fact

Every result starts with a controlled comparison

BulbFacts tests actual products in actual headlight housings so shoppers can compare brands and models against the same reference points. Results are meant to show relative performance under controlled conditions, not guarantee identical output in every vehicle.

  • Products are purchased or obtained as real retail-style samples whenever possible.
  • Testing is performed in a dark environment with consistent voltage and controlled warm-up timing.
  • Peak lux, beam behavior, color temperature, lumens, power, heat, noise, and compatibility notes are recorded where relevant.
  • BulbFacts does not accept paid rankings, sponsored review outcomes, or manufacturer control over results.
BulbFacts headlight housing test bench
Controlled housing tests help compare usable output instead of relying on package claims.
Product scoring basics

For LED products, 5.0 is good. 7.5+ is excellent.

The original BulbFacts product score scale was built around a 5.0-ish upper range, but newer LED kits became bright enough to push beyond that older ceiling. Treat LED scores as comparative BulbFacts product ratings, not a normal 10-point school grade. Halogen, HID kit, and Xenon pages may use category-specific scoring notes.

1.0-2.9Low performer or poor match for the category
3.0-4.9Usable, but not usually a top recommendation
5.0-7.4Good to very strong measured performance
7.5+Excellent result on the current BulbFacts scale

On this page

General testing rules

BulbFacts uses specific automotive housings and repeated procedures so each product in a category is compared against the same baseline. Common test sizes include H7, H11, 9005, and D-series HID bulbs depending on the category. Other vehicles and housings can behave differently, so the charts should be used as controlled comparison data rather than a vehicle-specific guarantee.

VoltageMost headlight testing is performed around 12.75 volts unless a product category or long-term test requires a different stated setup.
MeteringBeam lux readings use an Extech LT300 light meter. LED glare-point checks may also use an Extech LT40 LED light meter.
Power sourceBench testing uses a regulated Korad KA3010D power supply for repeatable voltage and current control.
EnvironmentBeam and lux testing is performed in a dark test environment to reduce outside light interference, usually around 66-68°F ambient.
Warm-upReadings are taken after defined warm-up times, commonly 2 minutes for halogen and LED output and 5 minutes for HID output.
PhotosBeam images are captured with consistent camera settings when possible, though older photos may reflect older test procedures.

LED test details

LED kits are compared against a stock halogen reference and measured in reflector and projector-style headlight housings. Because LED conversions can vary dramatically by housing, BulbFacts looks beyond raw brightness and includes beam quality, glare, power draw, heat, noise, DRL behavior, and CANBUS-style load notes when available.

Reflector headlights

Reflector low and high beam results use OEM halogen reflector housings at 25 feet, including a 2013 VW Jetta reflector setup for H7 testing and a 2013 Buick Lacrosse reflector setup for H11/H9 testing where applicable. Percentage values are compared to a new stock-style halogen reference.

Projector headlights

Projector results use OEM projector housings at 25 feet, including a Hella premium bi-halogen projector and additional OEM projector housings when a kit is not available in the primary size. These results help show whether an LED kit works in a focused projector beam, not just a reflector housing.

Glare, CANBUS, and ownership notes

Version 2.1 added glare figures for LED reflector tests. Glare is measured from 9 feet away, 2.64 inches above center focal height, and 2.85 inches left from center focal using a driver-side headlight position. These glare-point checks use the same controlled setup and may use the Extech LT40 LED light meter for LED-specific readings. A 93 lux glare reading represents a rough maximum comfort reference, or about 700 candela in that setup.

CANBUS / bulb-out compatibility is a bench-based load estimate. LED products are tested against the stock halogen electrical load: 50% or more is labeled CANBUS-friendly, 40% to 49% may need a decoder, and under 40% is listed as likely requiring a decoder. Actual vehicle behavior can still vary by BCM sensitivity, DRL strategy, PWM, wiring, and monitoring logic.

Halogen test details

Halogen bulbs are compared against a stock OSRAM-style halogen reference in controlled reflector and projector setups. The halogen charts focus on measured output, color temperature, lumens, claimed or tested life where available, price, and practical upgrade value.

Reflector headlights

Reflector beam results use an OEM 2013 VW Jetta halogen reflector housing at 25 feet. Results are compared against a new OSRAM Original / stock-style halogen bulb, with peak lux and percentage differences shown in the charts.

Projector headlights

Projector testing uses an OEM 2009 Mercedes E550 halogen low-beam projector and an OEM 2017 Kia Sorento halogen high-beam projector at 25 feet. This helps show whether a halogen upgrade performs differently in a projector than it does in a reflector.

Lumen output is measured with a TES-133 luminous flux meter, with readings taken after warm-up. Color temperature is measured through the headlight output rather than from the bare bulb, so the Kelvin value reflects what the tested housing produced on the wall.

Halogen lumens are measured per bulb at 2 minutes of runtime with ambient cooling. Lifespan ratings, where available, are based on controlled long-term runtime samples and should be treated as comparative data, not a guarantee.

Aftermarket HID kit test details

Aftermarket HID conversion kits are primarily evaluated in projector-style headlight tests because HID conversions can create serious glare and beam-control problems in unsuitable reflector housings. HID bulbs are burned in before measurement so lux and Kelvin values stabilize.

Projector testing uses OEM projector housings at 25 feet. Kits are tested with the ballast included with the product unless otherwise noted, and results include brightness, color temperature, lumens where available, ballast wattage, price, and practical notes.

Xenon bulb test details

Xenon replacement bulbs are D-series style factory-replacement bulbs, not aftermarket HID conversion kits. These are tested in factory bi-xenon projector lens assemblies with a 35 watt ballast at 25 feet.

Bulbs are burned in before final lux and Kelvin readings. Scores are weighted around measured low and high beam output for the category, and percentages are compared against a stock OSRAM HID reference bulb.

Important limitations

Test results are based on the sample tested, the equipment used, and the process in place at the time. Manufacturing changes, sample variation, installation, voltage, headlight aim, vehicle housing design, and environment can all change the final result in your vehicle.

BulbFacts results are not legal approval, safety certification, or a guarantee that a product is suitable for public-road use. Always confirm fitment, legality, safe installation, and proper headlight aim for your own vehicle.

Test details last updated June 15, 2026. If you see a test note or chart result that needs clarification, please send it through the contact page.
Use the data

Compare current charts

The process explains the method. The charts show the current product comparisons.

LED chartReflector results Halogen chartOE-style bulbs Xenon chartD-series Xenon bulbs