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Wattage vs Lumens: Know the Difference for Better Lighting

Posted by SEPCO

7/10/14 9:30 AM

Wattage-vs-LumensWith the push for LED lighting, there is a lot to take into consideration now for lighting levels. One of the biggest arguments is a light Wattage versus the Lumens and determining brightness. The old way of looking at how bright a light will be is to look at the wattage; the higher the wattage the lamp is, the brighter it is. Now we need to focus on the Lumens of the lamp to determine the brightness of the lamp.

What is Wattage of a Light?

The Wattage of the light is the amount of energy it takes to produce a certain amount of light. The higher the wattage, the brighter the light, but also the more power it uses. The efficiency of this system was introduced using incandescent lamps.

For instance:

  • 40 Watt lamp produces only 380-460 lumens and uses 40 Watts of energy per hour.
  • 100 Watt lamp produces 1700 – 1800 lumens and uses 100 Watts of energy per hour.
  • Direct sunlight is around 100k lumens and uses no amount of energy per hour.

This was an inefficient way of lighting and there have been many advances, such as the introduction of fluorescent and compact fluorescent lighting as well as metal halide, low pressure sodium and high pressure sodium. Fluorescent and compact fluorescent produce better lighting with lower wattage. Metal halide, LPS and HPS produce better lighting, but typically using much higher wattage.

What is a Lumen of Light?

A lumen is the amount of light a certain lamp gives off. If replacing a standard 150 Watt light bulb which gives off around 2600 Lumens, using a 35 Watt LED is about the equivalent. This lowers the needed power of the light by over a quarter of the required power to produce the same light. A 70 Watt LED fixture can produce 5000 Lumens or more and replace most highway and parking lot lighting fixtures to a more efficient and cost effecting light. This is becoming more efficient every day.

Why this is important to solar lighting

Solar lighting needs to take into consideration both the Lumens and the Wattage of a lamp. The wattage provides the needed power from the solar power and battery system to power the solar light fixture for the required amount of time and the Lumens determines how much light is given off by the lamp. The more efficient the fixture or lamp is, the more efficient the solar and the lower the cost of the complete system. Solar lights are also typically lower to the ground and then can produce more lighting with a lower Watt lamp and using a higher Lumen efficiency. Want to know more about solar and LED lighting, check out: Why Solar Power and LED Lighting Makes a Perfect Combination

In the end, taking into consideration the lighting levels and Lumens over the Wattage of the lamp will provide a more energy efficient lighting system. Higher Lumen and lower Wattage lamps, especially with LEDs, will provide the best lighting with the lowest energy costs.

Topics: Solar Lighting, General Lighting, LED Lighting, Solar Lighting Design

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