“The higher the wattage, the brighter the bulb” is a common myth when purchasing LED bulbs. Often, after buying a high-wattage bulb, you find that it is not bright enough and consumes more power… Faced with numerous LED bulb choices, how do you find the right LED brightness? This article will sort out LED brightness calculation methods and LED comparison tables for you to help you understand LED brightness levels, find suitable LED bulbs, and solve space lighting needs.

LED brightness calculation | 3 common terms to understand LED

When buying LED lights, you often see three terms: wattage, lumens and luminous efficiency. The following will explain the three terms to help you understand the LED brightness level and help you choose the appropriate LED brightness.

1. Lumens: LED brightness unit

Lumens（lm) is the unit of luminous flux (Luminous flux), and luminous flux represents the brightness perceived by the human eye. Therefore, the higher the number of lumens, the brighter the LED. The calculation method of luminous flux is “wattage luminous efficiency”. Taking an 8-watt LED bulb as an example, the luminous efficiency is about 60 lumens/watt, then the luminous flux is 860=480lm.

2. Wattage: power consumption of electricity

There is not much difference in the luminous efficiency of traditional light bulbs, so wattage is usually used as a reference for brightness. However, in fact, what the wattage really affects is not the brightness, but the power consumption rate. The larger the wattage, the more power it consumes.

3. Luminous efficiency: number of lumens produced per watt

According to the above “luminous flux calculation formula”, luminous efficiency = luminous flux wattage. When the required brightness is the same (the same luminous flux), LED lights with higher luminous efficiency require smaller wattages than traditional light bulbs, and therefore save more power. For example, if the required brightness of the space is 720lm, when purchasing an incandescent lamp (luminous efficiency of 12 lumens/watt), you need to choose a 60-watt product, and when purchasing an LED lamp (luminous efficiency of 60 lumens/watt), you only need 12 watts. Therefore, the LED lamp The power consumption is about 1/5 of that of incandescent light bulbs.

In summary, when choosing an LED bulb, the brightness depends on the luminous flux, and if you want to save power, look at the wattage. If you want to reduce power consumption at the same brightness, it is recommended to choose products with higher luminous efficiency.

LED brightness adjustment｜Incandescent bulb and LED comparison table

After understanding the calculation method of LED brightness and learning the principles for purchasing light bulbs, I will introduce you to the brightness required in different spaces, and sort out the wattage comparison between incandescent light bulbs and LED light bulbs to help you find the right product.

Reference: https://www.ethanvision.com.tw/淺談led亮度等級/#3發光效率：每瓦產生的流明數