Most modern lighting solutions use light-emitting diodes (LEDs) instead of traditional incandescent or halogen bulbs. LEDs are typically more energy-efficient, offer better illumination, and last significantly longer. However, one common downside is their tendency to glow even after being turned off.
If your LED light continues to glow when switched off, it’s often due to poor installation or low-quality bulb. The afterglow may result from residual energy in the bulb or issues within the electrical circuit. In most cases, you’ll need to replace the bulb or regulate the circuit’s voltage.
While LED lights are efficient and long-lasting, the lingering glow can be frustrating. In this article, we’ll explain why it happens and how you can fix it.
1. Replace the LED Bulb
It’s pretty normal for an LED bulb to glow a few seconds after switching it off since they inherently have a higher resistance which affects the power supply. However, if the glow becomes constant or lasts for more than a few minutes, it may result from substandard workmanship or inferior materials used to make the bulb. Poor-quality LED bulbs may also buzz and flicker when turned off.
You can determine where the problem lies by removing the bulb from the socket. If the bulb glows once it’s removed, then the problem is with the bulb. But if the light stops glowing when removed from the socket, the problem is with the circuitry.
The quickest way to address the issue with a faulty LED light is to replace it with one from a reputable brand. You can replace most LED bulbs without professional help since they usually have a screw or pin-type fitting.
The most common fittings for LED bulbs are:
- E27: Screw thread bulb fitting
- GU10: Pin-type bulb fitting
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Before attempting to replace any bulbs in the house, take the following precautions:
- Allow the bulb to cool down
- Ensure the lights are switched OFF to avoid electrocution
- Use protective gloves if the bulb does not have a protector
To replace an E27 bulb, simply unscrew the old light bulb by turning it counter-clockwise and then replace it with a new one by screwing it on clockwise. For GU10 bulbs, twist the old bulb 90 degrees counter-clockwise to remove it, and install the new one by rotating it clockwise until it snaps into place.
If you’re uncertain about the fittings or if the LED lights are hard-wired, it’s best to consult a certified electrician. For safety reasons, you should never try to tinker with electrical wiring and circuits if you’re not trained.
2. Install a Neon Indicator or Compact Fluorescent Light CFL
Another reason an LED bulb continues to glow is because of the energy left in the LED driver or the bulb’s luminescent (or phosphor) layer.
LEDs usually have a luminescent layer to give them their color. This layer of phosphor can store residual energy, which may become evident in the form of a slight glow. The strength and duration of the glow will vary depending on the wattage and materials of the bulb.
LED bulbs also have LED drivers, which contain inductors and capacitors to provide the appropriate current for the bulb to work. These components can also store energy causing the bulb to glow after turning the switch off. The light within the driver will continue to be visible until completely discharged.
You can soak the residual energy by installing either of the following:
- Neon Indicator
- Compact Fluorescent Light (CFL)
A neon indicator can absorb the excess charge, which will cause it to light up instead of the LED bulb. There will still be a presence of light from the indicator, but it will be far less illuminating compared to an LED bulb’s afterglow.
Neon indicators are easy to find; there are many online, or you can remove one from an old appliance like a kettle or blender. To install the indicator, connect the wires to the neutral and lone lines and ensure the indicator’s voltage range is compatible with the circuit to avoid any issues.
Alternatively, you may also use a CFL to redirect any surplus voltage. By installing a CFL, no energy will be left to illuminate the LED bulb when switched off.
3. Install a Zener Diode
As previously stated, if you remove the LED bulb from the socket and it stops glowing, the problem is most likely with the circuit.
The wiring for light bulbs and switches contains three wires:
- Neutral
- Line
- Ground
If the neutral wire is not correctly earthed or the ground wire has too much resistance, it can cause the LED light to glow since some voltage may still make its way to the bulb after it’s switched off. Fortunately, you can overcome this problem by connecting a Zener diode.
Zener diodes are usually made of silicone and contain a p-n junction, which serves as a boundary between the semiconductors. As a semiconductor, a Zener diode can make the current flow backward to keep it from illuminating the LED bulb when it isn’t turned on.
For a Zener diode to work properly as a regulator, you will need to ensure the cathode terminal of the diode is connected to the positive rail of the power supply. If this sounds greek to you, it would be best to have the work done by a technician.
4. Install Bypass Capacitors
It’s not uncommon for stairways and long corridors to use parallel cables for two-way connections, where you have two switches for one light. Households mainly use parallel circuits to ensure the other lights continue to work if one happens to fail.
The problem with parallel cables is that the conductor is prone to electromagnetic induction, particularly when cables run alongside each other over long distances. A current is created due to the electromagnetic fields near the conductors. This occurrence can leave a small voltage that will continue illuminating the light bulb after switching it off.
You can resolve this issue by installing a bypass capacitor in the lights. Connect the bypass capacitor between the supply voltage and ground pins to reduce electrical noise and prevent electrical spikes.
Capacitors can temporarily store energy and absorb any remaining voltage, preventing the LED bulb from flickering or glowing when not in use. Bypass capacitors are inexpensive, but you may need the help of an electrician to install them.
5. Replace the Dimmer or Light Switch
Upgrading to LED from incandescent bulbs without replacing the light switch or dimmer may also cause them to illuminate when off. Not all LED lights and dimmers are compatible since older dimmers do not meet the specifications for modern lighting. Furthermore, some LED lights are not dimmable.
Since LED lights are more efficient, they may not supply enough power to reach the dimmer’s minimum load requirement to work correctly. Failure to meet the load requirement of the dimmer prevents it from switching off its output voltage, causing the LED bulb to light up faintly when turned off.
The obvious remedy here is to replace the dimmer with a new one, but you also need to ensure that the replacement will work well with your lights. Old dimmers have a variable resistor that controls the light’s illumination by increasing or decreasing the amount of energy sent to the bulb. Modern dimmers will only work with LED bulbs that have dimmable drivers, so you need to ensure the bulb and dimmer are compatible.
The Lutron Dimmer Switch (available on Amazon) was tested on 1000s of bulbs and is compatible with many popular LED light bulb brands. It allows you to select from 250 different lighting levels and uses patented technology to optimize its dim range without interfering with the other dimmers in the house.
To check whether your light bulb is compatible with the Lutron dimmer, simply enter your bulb’s SKU or UPC number in their compatibility tool.
It takes less than 15 minutes to replace a dimmer switch, but it’s best to reach out to a qualified technician if you’re uncertain about the procedure.
6. Fix Light Switches With Night Light
Aside from dimmers, light switches with integrated night lights can also cause issues with LED bulbs. If the light switch has a glow lamp connected in series, it may cause the bulb to stay lit since LEDs have their power supply. You can address this issue by disconnecting the glow lamp or replacing the switch with an additional terminal for a neutral wire.
In Conclusion
It may not be uncommon for LED lights to glow when turned off, but the good news is that this is not an inherent trait. Many LED bulbs from reputable brands offer decades of trouble-free illumination. If you continue experiencing problems with a branded bulb, the problem may be with the circuit.
Most issues with LED bulbs stem from irregular voltage supply or incompatible switches, which can quickly be addressed without costing you an arm and a leg. Going back to incandescent or halogen bulbs will definitely cost you more when your next electricity bill is due.
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