Hi everyone,
I’m thinking about getting dimmer switches for my lights. My main question is simple: Does using a dimmer make light bulbs last longer, or does it make them burn out faster?
I’m curious if this changes for different types of bulbs. For example:
Old-style incandescent bulbs: What happens to their life when dimmed?
Halogen bulbs: Do dimmers affect these differently?
LED bulbs: With modern LEDs, does dimming help or hurt their lifespan? And how important is it to use the right dimmer with an LED bulb?
Thanks for your input!
Hi oafh1,
That’s a great question, and the answer actually varies quite a bit depending on the type of bulb you’re using!
Here’s a breakdown based on my understanding and experience:
1. Old-style Incandescent Bulbs:
Dimming extends their lifespan significantly. Incandescent bulbs work by heating a filament. When you dim them, you’re reducing the power flowing to the filament, which means it operates at a lower temperature. This greatly reduces the rate of evaporation of the tungsten filament, which is the primary cause of failure. It’s not uncommon for an incandescent bulb that’s consistently dimmed to last many times longer than its rated lifespan.
2. Halogen Bulbs:
Dimming generally extends their lifespan, but there’s a caveat. Halogen bulbs are a type of incandescent bulb, so reducing the operating temperature through dimming still helps extend the filament’s life. However, halogen bulbs rely on a “halogen cycle” where evaporated tungsten atoms are redeposited back onto the filament. This cycle is temperature-dependent. If you dim a halogen bulb too much or for prolonged periods at very low levels, the halogen cycle might not complete effectively, which could lead to blackening of the bulb and eventually failure. For most practical dimming uses, though, you’ll still see an extended lifespan.
3. LED Bulbs:
This is where it gets more complex.
Dimming generally does not significantly shorten the lifespan of the LED emitter itself. LEDs typically fail due to degradation of the semiconductor material over time, which is related to heat and current. Dimming usually means less current and less heat, so the LED chip itself often benefits or is unaffected.
The lifespan impact often comes from the driver/electronics within the LED bulb. Modern LED bulbs have internal electronics (the “driver”) to convert AC household current to the DC current the LED needs.
Using the right dimmer is crucial. If you use a dimmer that’s not compatible with your LED bulb, it can cause flickering, humming, or stress the internal electronics, potentially shortening the bulb’s lifespan. LEDs typically require “leading edge” or “trailing edge” dimmers designed for them. Many older dimmers (designed for incandescents) can cause issues. Always check the bulb’s packaging or manufacturer’s recommendations for compatible dimmers.
Quality of the LED bulb matters. Cheaper LED bulbs might have lower quality drivers that are more susceptible to issues from dimming, even with a compatible dimmer. Higher quality bulbs generally have more robust drivers.
Overall: When properly dimmed with a compatible dimmer, LED bulbs are not typically shortened in lifespan, and in some cases, running them at lower power might even slightly extend the life of the LED emitter. The main concern is ensuring proper compatibility to protect the integrated electronics.
In summary:
Incandescent & Halogen: Dimming is good for lifespan.
LED: Dimming is generally neutral to slightly beneficial for the LED emitter, but dimmer compatibility is paramount to protect the bulb’s internal electronics and ensure proper function.
Hope this helps with your decision!