When it comes to HID replacement, Corn Cobs may seem like the obvious choice, however whilst Corn Cobs are still recommended for some specific applications, there are several aspects that, generally, make Filament lamps the better choice. But first:

What is a Corn Cob Lamp?

“A corn lamp is an assembly of light-emitting diodes(LEDs) on a metal structure. They are called corn lamps because the manner in which the yellow LEDs are assembled on the fixture resemble corn kernels on a corn cob. Corn cob lamps are meant to provide a high output of light using LEDs, which requires a large amount of diodes. The diodes (which sometimes can number in the hundreds) are mounted to a metal “cob” that has as much surface area as possible to keep the diodes cool. Since the fixture is cylindrical, it’s appearance is similar to a cob of corn, thus earning it the name of a “corn lamp” or “corn cob lamp.” Regardless of the name, though, these fixtures are well known in the lighting industry for their high light output and low energy usage” – https://shineretrofits.com/blogs/lighting-center/corn-lamps

What is an HID Replacement Filament Lamp?

“HID replacement filament lamps are designed to replace traditional HID lamps with energy-efficient LED technology. These lamps offer the familiar look and feel of conventional HID lamps while providing significant energy savings and long-lasting performance.” - https://www.rablighting.com/feature/filament-hid

Form Factor

Filament lamps are the exact same ANSI bulb shapes as traditional HID lamps. They’re sized from ED17 through ED37. They can be fitted into any existing fixture, without the need for measuring beforehand. Corn cobs, on the other hand, use a cylindrical design which makes them significantly different from the shape of a traditional HID. Because of this, fixtures where a Corn Cob will be used must be measured before any orders are placed. For easier installation, Filament lamps are the obvious winner.

Light Distribution

Filament lamps have 360 degree, fully luminous light distribution, the same as traditional HID lamps. Corn cobs use LED panels that are arranged around a cylinder. As a result, there are panel gaps and there is not the same, uniform, light distribution. For consistent luminous light distribution, Filament lamps are the better choice.

Performance

Traditional HID lamps produce 50-100 lm/w. Filament lamps produce 200 lm/w. Corn Cobs produce 148 lm/w. Filament lamps are 80% energy saving whereas Corn Cobs are 70% energy saving. Therefore, with energy saving in mind, Filament lamps stand out as the best.

In conclusion

Filament lamps are the better choice for Post Tops, High Bays, Wall Packs, Heritage Fixtures, Area Lights and Dusk to Dawn. Corn cobs are best used for specific applications : 277-480V systems, 450W+ HID replacements and IP64 applications. Overall the Filament lamp has better form factor, better light distribution and higher efficiency.