Does Dimming LED Lights Save Energy?

Jan 13th 2020

LED lights are continuing to grow in popularity in commercial and residential applications across the country because of the tremendous efficacy they offer.

However, LED lighting is still relatively new to many people and there are lots of questions regarding its efficacy that aren't apparent. One question we keep getting regarding our LED lights is whether dimming LED lights saves energy and if so, what type of dimming setup is to be preferred?

As we consider dimming to be an integral aspect of choosing your LED lights, we decided to give you an overview.

The Short Answer

Yes! Dimming LED lights saves energy.

With that said, not all LED lights are dimmable. Some come with preinstalled dimmability options while some fixtures are compatible with external dimming setups. When you’re shopping for LEDs, be sure to look for the dimmability icon that suits your needs and check the list of dimmers we recommend.

dimmable icons

How does dimmable LED work?

To understand how dimming an LED light works, we'll give you a quick crash-course on how light emitting diodes (LEDs) work and how different dimmability options come with unique set of pros and cons.

There are two main ways to dim LED light: pulse width modulation (PWM) or analogue dimming.

Pulse Width Modulation (PWM)

Pulse width modulation systems work by turning LED lights on and off faster than our brains can comprehend. By being off for about 75% of a second and on for about 25%, a dimmable LED bulb will appear to emit the equivalent of 25% its total potential brightness.

It sounds a little crazy at first, but it’s actually closely related to the “flicker fusion” principle that makes movies appear to be happening in real time, even though they are a series of still images.

If you’re in a room with PWM LEDs, you won’t perceive any flashing or flickering, but you will gain more specific control over your dimmability and energy usage.

As the graphic above illustrates, PWM technology brightens or dims LED bulbs by increasing the amount of time the light is on per cycle. That provides advantages, such as…

  • Minimal energy loss
  • Increased brightness range with consistent, controllable levels
  • Minimal stroboscopic (flashing) effect
  • Consistent color quality
  • This doesn’t mean PWM is perfect for everybody. It does have some disadvantages, like:

  • Dimming cycles can potentially create a buzzing sound some people can hear
  • The ceramic parts used in inexpensive PWM systems can vibrate in a way that distorts light and reduces precision control over dimming
  • Analogue Dimming

    An analogue dimmer directly controls the flow of energy into the LED, raising or lowering the brightness of continually operational lights. Unlike a PWM dimmer, which rapidly switches the light on and off, an analogue system provides a continuous flow of exactly enough energy to achieve your lighting goals.

    In the case of analogue dimming, an LED driver serves as a switchbox where DC voltage can be increased or choked back to control the flow of power to the light. This has a number of benefits, including…

  • Zero output noise
  • Great control over LEDs with lower demand
  • Of course, like PWM, analogue dimming also comes with disadvantages, such as:

  • Color shift: as your voltage changes, the quality of your light might not remain consistent
  • Lower efficiency: there is always some energy loss occurring
  • Limited dimming range: depends on the incoming current and the quality of the driver
  • 0-10v and 1-10v Dimming

    One of the most common forms of analogue LED dimming technology on the market is known as “0-10V.” 0-10V is an updated version of the protocol used to dim the fluorescent lights that were popular in offices, schools, and so on in the past.

    Basically, 0-10V dimming works by scaling the output of the LED light mathematically. At a 10-volt supply, the dimmer provides 100% of the light’s pull potential. At a 0-volt supply, the dimmer provides 0% of the light’s potential.

    0-10V dimming provides the some of the best advantages of analogue technology as:

  • Simple change-over from a legacy fluorescent system
  • Affordable method
  • Compatibility with a wide range of dimmer switches

  • The drawbacks of 0-10v dimming is that it is not suitable for installations where each light requires its individual dimming percentage. When multiple LED drivers are connected to the same dimmer, they all respond identically to the dimmers current setting.

    How is Dimming LED Lights Different from a Traditional Dimmer?

    On the other hand, you can dim and brighten LED lights without any energy waste. When you adjust the dimmer on an LED system, your power usage goes up or down in a way that’s directly proportional to the wattage you’ve selected.

    To put it simply, if you dim your LED lights 50%, they use about 50% as much energy!

    Dimmable LEDs provide you with the most precise, predictable control over your energy usage that’s ever been possible. You can choose exactly how much light you need in given spaces or during specific times of the day and limit your overall carbon footprint without having to turn the lights all the way off.

    By making the transition toward LED dimming, offices, schools, and other large buildings can make the most of daylight harvesting and other lighting-related workplace initiatives. Homeowners can also install LED dimmers to reduce their monthly electric bills while creating greater ambiance throughout their house.

    The lifespan of LED bulbs can vary greatly depending on environmental factors. The generally accepted range is between 10,000 and 50,000 hours .

    Of course, brightness is one of the factors that impacts LED lifespan. The brighter your LED diodes, the hotter they run. By dimming your lights, you’re reducing heat stress and protecting your bulbs.

    By installing an LED dimmer, you can protect the health of your lighting system, maximize the life of each bulb, and save money without sacrificing light.

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