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Can you dim smart bulbs? Everything you need to know right here!

Dimming Light

Smart bulbs are becoming a common place fixture in the homes of America, and even across the world. However, they have taken a simple thing, the light bulb, and made it more complicated, to the point where you have to ask if you can dim the bulb.

To answer your question, Can you dim smart bulbs? Most smart bulbs are designed so that they can be dimmed using their associated app. The smart bulb then uses software to control the brightness level. Smart bulbs cannot be dimmed using a standard dimmer, and may even cause damage to the bulb.

Who knew that dimming a light bulb could be so complicated? By the end of this article, you will know everything you need to know about dimming a smart bulb, as well as things not to which could result in damage to a smart bulb, or possible even a fire.

Standard Dimmer Switches

What is a standard dimmer switch?

I am going to be talking about a couple types of dimmer switches, so I would like to make sure that we’re all thinking the same thing when I say standard dimmer switch.

When I say standard dimmer switch, I’m talking about your standard wall dimmer switch that can turn on and off a light, as well as control how bright or dim the light is by moving a slider or turning a knob.

They can take on several the form in different shapes and sizes, such as being a round knob that you twist or a rectangular switch with a slider. They are usually mounted in a switch box that is recessed into the wall. A face plate is used to cover the rest of the hole in the wall and any exposed wires, just like any other switch that is mounted in the wall.

Here’s a picture of an old-fashioned (I guess the 90’s are old-fashioned now.) dimmer switch.

Round Dimmer Switch
Round Dimmer Switch
Sliding Dimmer Switch
Sliding Dimmer Switch

How does a standard dimmer switch work?

If you are not into electrical technical jargon, you may want to skip this section. Still, I’m going to keep the detail pretty light.

Modern dimmer switches use semiconductors and the fact that power to your home is AC (Alternating Current). Inside the dimmer, a semiconductor is used to turn on power to the bulb, depending where the voltage level is at in its cycle on the input side.

A potentiometer (basically a resistor that has variable resistance) is connected to the semiconductor inside the dimmer switch. The resistance value, controlled by the potentiometer, determines how high (or low) the voltage needs to be before the semiconductor turns on. The potentiometer is controlled by the sliding action on the switch, or when you turn the knob.

Here is an example of what the input and output may look like:

Waveform of the output voltage of a thyristor dimmer set for 60 volts RMS output, with 120 V input. The red trace shows the output device switching on about 5.5 ms after the input (blue) voltage crosses zero. Switching the thyristor on earlier in each half cycle gives a higher output voltage and brighter lights.
Wikipedia

In layman’s terms, the switch is turning on and off really fast. 120 times per second to be exact. The longer it is turned off, the more dim the bulb appears.

How Using a Standard Dimmer Switch May Damage Smart Bulbs

Smart Bulbs can handle being turned on and off at the speed a human would typically use a normal on/off switch, but it’s not designed to be turned on and off 120 times a second.

Inside your smart bulb is basically a micro-computer. There is a circuit card with a few chips on it that are designed to run at a steady voltage.

Part of this circuit cards function is to control power, which relies on a steady power supply. Its job is also to protect the other elements on the circuit.

It may not be able to do its job if the power is turning on and off at such a fast rate.

Secondly, the micro-controller portion takes time to boot-up, just like a computer. You’ll notice that once the bulb is turned on, it takes a few seconds to connect to Wi-Fi. This is part of the boot-up process. (Plus the time it takes to connect to Wi-Fi.)

Even if the circuit card isn’t fried, the circuit probably can’t keep up with the constant on and off. You may notice unexpected behavior. One of the most common behaviors is that the light will sporadically turn on and off.

The only way you can use a dimmer switch is to only use the on and off function and to keep the dimmer portion set to full power, which isn’t really using it as a dimmer switch, is it?

In short, it’s possible to use a dimmer switch and not damage the Hub Bulbs, but it’s probably best to replace the switch with something else.

Don’t use Dimmable Smart Plugs Either

In case you are thinking of using a dimmable smart plug, don’t use one of those either. The dimming function of a dimmable smart plug is not compatible with smart bulbs.

However, if you want to just use a normal smart plug to turn on and off the smart bulb, that should be fine. Just keep in mind that you will be loosing the smart functions of the smart bulbs when it isn’t supplied with power.

Smart Dimmer Switches

What is a Smart Dimmer Switch?

Seems like a simple question, but this is where things start to get confusing. There are two types of switches that manufactures may be talking about when they say smart dimmer switch.

First though, before we get into those details, here are the things that those smart switches have in common. Smart switches will have some sort of wireless connection, either Wi-Fi, Zigbee, or Z-wave. And they switches are dimmers, so they provide someway to dim the light, either through the app, or through the physical switch itself, or both options.

Now for the difference.

What Smart Dimmer Switches Can I use with a Smart Bulb?

Smart Dimmer Switches that do not directly control power to the smart bulb, or bulbs, can be used to effectively control the smart bulb through a wireless connection. Switches that are connected by wire directly to the bulb should not be used to control smart bulbs.

This seems to be a naming connection that the industry has not standardized yet. I suspect we’ll see naming differences in the future, but for now this is the way things are.

The reason that smart dimmer switches that directly control the power to the bulb cannot be used is:

  1. A smart bulb needs to always be supplied with power, so that it can be connected wirelessly. This is what gives the bulb its smart functions.
  2. The same reason you can’t use a standard dimmer switch.

Inside your smart bulb is basically a micro-computer. There is a circuit card with a few chips on it that are designed to run at a constant, steady voltage.

Smart Bulbs can handle being turned on and off at the speed a human would typically use a normal on/off switch, but it’s not designed to be turned on and off 120 times a second, like how a dimmer switch controls the brightness of a standard dimmable light bulb.

How to Identify if a Smart Dimmer Switch Can Control a Smart Bulb

Okay, you are probably wondering how do you tell if a smart dimmer switch is compatible or not.

Let’s start with signs a switch is not compatible with a smart bulb.

  1. The smart dimmer switch needs to be physically wired into the wall.
  2. The smart dimmer switch has phrasing on the package that says “single-pole” or “double-pole”

If your smart dimmer switch has a diagram that looks something like this, that means it is able to directly control power to the bulb. It should not be used with your smart bulb.

Smart Switch Wiring Diagram
TP-Link Smart Switch Wiring Diagram

Now for the signs a switch IS compatible with a smart bulb.

  1. The smart dimmer switch has phrasing that indicates “no-wiring needed.”
  2. The smart dimmer switch does not need to be recessed into the wall for installation.

These are signs that the smart dimmer switch is controlling the smart bulbs through a wireless connection between the bulb and the switch, with the hub or router being the middle man.

Just a quick summary. Smart bulbs need to be supplied with full power to work correctly. Don’t use any dimmer switches or plugs that don’t supply full power. It is okay to use smart dimmer switches that control the smart bulb’s brightness by sending it commands wirelessly.

Ways to Dim a Smart Bulb

Now that you know what dimmer switches are appropriate to use with a smart bulb, here are the ways you can control a smart bubs brightness.

Through the App

Here’s a video that show’s how to use an app to control a smart bulbs. This app is for a particular brand, but most of the other brands out there have some sort of similar interface for controlling the smart bulb.

Also, this video demonstrates installing and setting up a smart bulb, as well as using voice control. I’m going to start the video at the part where he is using the app to control the light though.

Through Home Automation (Plus Scheduling)

There are many ways to setup home automation. IFTTT is a common tool for doing this, and below is a video demonstrating home automation using Google Home Routines. The video also demonstrates how you can schedule certain events to happen at various times throughout the day, such as turning on the Christmas lights when it gets dark. I few scheduling as a subset of home autmation.

Through a Smart Dimmer

I’ve already briefly discussed how to use a smart dimmer switch to control your smart bulb, but their are a few more details that I need to delve into.

The most important of these is that the smart switch and the smart bulb need to be able to communicate with each other. This usually means that they use the same type of wireless communication. IF a bulb uses Wi-Fi, you will need a Wi-Fi Smart Switch. The same goes for other popular protocols such as Zigbee or Z-Wave.

The exception to that rule is when the communication goes through a hub which is able to communicate with multiple device types. This can happen with Zigbee or Z-Wave devices, which need a hub. The hub will connect to your home internet, and may be able to send commands to your Wi-Fi devices.

Using Your Voice

Lastly, there is the option to control your smart bulb by using only your voice. This is done by using Google Home, or Alexa. Apple’s Homekit is also starting to gain some popularity.

It’s also an option to use multiple voice assistants. Here’s a video demonstrating the use of voice assistants to control your smart bulb. It also shows how to connect the smart bulb to those systems.

How Much Can You Save By Dimming Lights?

Lights are dimmed by making them flash really fast. Faster than the human eye can perceive. The difference between the time that are turned off and the time they are turned on is what controls how bright the light is. This is how the dimming function works in smart bulbs as well, just all the control is internal to the bulb, instead of having to have a separate dimmer switch like those old “dumb” bulbs need.

Since a dimmed bulb is not turned on constantly, it is saving power. And saving power means saving money. So Dim away! Dimming a light bulb to 50% of its power, can save around 40 – 50% of it’s power use.

However, keep in mind that today’s smart bulbs use LEDs, which are already incredibly power efficient compared to incandescent bulbs or even CFL bulbs. While you may be saving a certain percentage of lighting energy, it is likely a small percentage of your overall household energy usage.

Your devices that are used to heat and cool are going to use a lot more energy. Household items like fridges, washers and dryers, and your HVAC system. If you’re interested on how you can save on HVAC cost, consider my recommendation for a smart thermostat.

Related Questions

Do Smart Bulbs Need a Dimmer Switch?

Smart Bulbs do not need a dimmer switch in order to be controlled or dimmed, but they can be dimmed using certain smart dimmer switches. Most Smart Bulbs have multiple options on how that can be dimmed, including through a smart phone app, home automation, or voice control through a voice assistant.

Does a Light Switch Need To Be On For Smart Bulbs?

Light switches that provide power to a smart bulb should be left in the ON position. Smart Bulbs require a constant power supply in order for their smart functions to work. Leaving the light switch on uses very little energy, although turning the switch off does not hurt the smart bulb if the smart features are not needed.