My wife and I have several lights on dimmer switches throughout our home. We generally prefer the ambient lighting provided by dimmed lights. I am curious, though, if we are saving any electricity by dimming the lights. I feel like I read somewhere that dimmers work by rapidly turning on and off the current to a light, though it's just as likely I fundamentally don't understand how a dimmer switch works.
Electrical – When I turn down the dimmer switch on the lights, do I actually use less electricity
electricallightingswitch
Related Solutions
You will need to check the product packaging or manufacture website to see what types it is listed for. All of the Leviton and Lutron products I see at Home Depot lately have clear markings on the packaging.
Lutron marks them as C-L and Leviton calls them "Universal Dimmers".
If your lights are 12V then you need a magnetic dimmers for low voltage lighting.
You've probably connected one of the 2 power wires to the incorrect traveler terminal on the switch.
This switch can be used as both a standard two-way switch as well as a three-way switch. (A three-way switch is used when there are 2 switches controlling the same device.)
In standard two-way arrangement, one of the power wires should be attached to the common terminal (this screw is a darker color than the others) and the other power wire should be connected to the terminal on the opposite side of the switch (according to this switch's wiring diagram). These two terminals are connected when the switch is flipped "up".
The third terminal (on the same side as the common terminal) is used only in three-way configuration. If you've connected your second power wire here instead, then the device will receive power when the switch is flipped "down" because this is when that terminal is connected to the common terminal.
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Best Answer
Yes. And here's why.
Rheostat dimmers
Old dimmers, used a variable resister to dim the light. Lets look at a simple example.
We can find total resistance (RT), by adding up all the resistance.
RT = R1 + R2 = 0 Ohms + 144 Ohms = 144 Ohms
Then we can find the total current (IT).
IT = ET / RT = 120V / 144 Ohms = .83A
We'll then calculate the voltage across each resistive load.
E1 = IT * R1 = .83A * 0 Ohms = 0V
E2 = IT * R2 = .83A * 144 Ohms = 120V
Finally, we'll calculate the total wattage (WT)
WT = V^2/R = 120V ^2 / 144 Ohms = 100 Watts
Lets see what happens when we increase the resistance of R1
RT = 200 Ohms + 144 Ohms = 344 Ohms
IT = 120V / 344 Ohms = .349A
E1 = .349A * 200 Ohms = 69.77V
E2 = .349A * 144 Ohms = 50.23V
WT = 120V ^2 / 344 = 41.86 Watts
As you can see, we've increased the resistance of R1 and effectively reduced the voltage across R2. And now we have a dim light.
Thyristor dimmer
Modern dimmers use a TRIAC, to reduce the amount of time the light is on. However, because of the circuitry in the dimmer, there is not a direct 1:1 energy savings. Dimming the light to 50%, will not equate to a 50% savings in electricity.
A typical waveform in an AC system would look like this.
A TRIAC prevents electricity from flowing every time voltage reaches 0, something like this.
So you end up with a waveform that looks like this.
With the TRIAC, the light is actually turning off and on 120 times per second. With every cycle, you're saving a small amount of power. Is it enough to actually see on your electric bill? I guess it would depend on how long the lights are on, and what percentage they are dimmed.