Brightness

For many years, people have estimated the brightness of a light bulb by its wattage. But wattage isn’t actually a measure of brightness, but the measurement of how much power the light bulb consumes.

LEDs are so efficient that the traditional measurement of wattage is no longer useful to estimate the brightness of an LED, so equivalent comparisons have become the method that helps us determine which product to use. For example, regular household LED lamps are sold as 40w , 60w or 75w equivalent.

The true measurement unit of luminous flux (or brightness) is the lumen (lm).  Lumen measurements are an acceptable method to compare LEDs to traditional light sources.

The following chart shows a roughly estimated comparison of different kinds of light sources at a glance.

Lumens (light output)Incandescent/ HalogenMetal Halide/ High Pressure Sodium (HID)FluorescentLED
     
35020w 8w3-5w
45040w 12w6-9w
80065w 16w8-12w
110075w 20w9-13w
1600100w 32w16-20w
2600150w 50w25-28w
2800 100w65w30w
3900 120w80w40w
5900 175w100w60w
7100 250w125w75w
11300 400w200w120w
38000 1000w 400w

 

We’re all familiar with common household Incandescent or Halogen lighting.  High Intensity Discharge (HID) lighting includes Metal Halide and High Pressure Sodium, used most often for street lighting and parking lots. Fluorescent technology has also become a common choice for a variety of applications.

But as the chart shows, LED lighting is the most efficient choice. Most LEDs deliver 70 to 110 lumens per watt. No other practical lighting technology can compare.

Next: Color