A Consumer Reports Study
Replacement headlight bulbs: A bright idea?
Premium replacement headlight bulbs are marketed as a functional and cosmetic improvement over the conventional bulbs found in most cars. The bulbs try to mimic the whiter, brighter light of the high-intensity-discharge (HID) lights found on some pricey vehicles. However, while these bulbs emit whiter-looking light, they don’t provide a consistent performance improvement in our tests.
Changes in lighting regulations in the mid-1980s allowed automobile designers to create aerodynamic headlight assemblies. These assemblies use a replaceable halogen bulb rather than an entire replaceable assembly. Headlight performance varies considerably depending on the assembly’s design, including reflector design and lens shape.
Expensive HID lights are a more recent innovation. CR’s tests have shown that HID lights can be brighter, but illuminated distances are often comparable to those of halogen bulbs. Premium halogen replacement bulbs attempt to offer some of the benefits of HID lights while retaining the vehicle’s original headlight assembly.
Bulb replacement is usually a simple task for most backyard mechanics.
MEASURING THE LIGHTS
CR tested five premium replacement bulbs, one from each of the top-selling brands: the APC Plasma Ultra White, GE Nighthawk, Philips CrystalVision, Sylvania SilverStar, and Wagner TruView. The bulbs are priced between $26 and $40 a pair (two to three times more than standard bulbs) and are sold in discount or auto-parts stores. All tested bulbs claim Department of Transportation-standard compliance; noncompliant bulbs may be marked as “for off-road use only.”
Tests were both subjective, to determine how well distant objects could be seen by the human eye, and objective, measuring bulb illuminance, or brightness.
Three test vehicles, a Chrysler Sebring, a Toyota Camry, and a Honda Ridgeline, were used to provide a variety of bulb sizes and original equipment (OE) performance.
Headlight distance is vital because the sooner an object is illuminated, the better the chance of avoiding it. Distance is measured outdoors on a moonless night, from a stationary vehicle. Black, unlighted signs were set up at various distances, and engineers recorded which were visible from each vehicle with each set of bulbs. Only one set of bulbs, the Nighthawk, improved low-beam sight distance for one tested vehicle, the Ridgeline. However, they reduced distance on the Camry. Generally, low- and high-beam distance either remained the same or decreased with replacement bulbs.
To test claims of increased brightness, CR measured illuminance, the quantity of light that reaches a particular area. Inside a dark building, a light sensor was placed at a distance 50 feet in front of each vehicle at different heights both on center and 8 feet to the right to simulate a roadway shoulder. Results showed some localized improvements, but no one bulb scored consistently better than OE. The Nighthawk and Plasma Ultra White improved illuminance in more tests than the other bulbs, some of which did not perform as well as stock bulbs.
Subjectively, all five bulbs emitted a whiter light than OE bulbs, which could appeal to buyers seeking the look of HID lights. Studies show that some drivers prefer driving behind whiter light than the more yellow light of most OE halogen bulbs, but that doesn’t mean you can see farther.
Some manufacturers claim that their premium halogen bulbs improve brightness without causing oncoming glare, a common complaint about HID lights. Oncoming glare is caused by a combination of bright lights and an inherent sharp light cutoff. This combination can exist in HID or halogen lights. Most of the tested bulb-vehicle combinations did not cause high levels of oncoming glare. But using whiter premium bulbs in the Honda Ridgeline increased glare to where it could be a discomfort for oncoming drivers.
BOTTOM LINE
Our tests showed that while they do yield whiter-looking light, premium aftermarket halogen bulbs don’t offer a consistent performance advantage over original equipment bulbs, and they can perform worse. Much of a headlight’s distribution of light is dictated by its reflector and lens, factors that remain unaffected by changing the bulb. And the combination of higher cost and some manufacturer specifications of a shorter life span than standard replacement bulbs add up to increased costs.
