Can You Leave Dimmers on Low Constantly?

dimmer low lg

Dimmers are devices used to lower the light intensity or the brightness of the light of your light fixtures. These tiny fixtures divert electricity from your light bulb by taking electricity flowing through the circuits and then switching it on and off. 

Most modern dimmers are designed to modulate between on/off very rapidly, making them safe for long-term usage. Dimmers operate at about 60°C (140°F) and will be warm to the touch. Some dimmers can operate at a maximum temperature of 90°C (195°F). Leaving dimmers on low constantly for long periods of time will cause the dimmer to overheat and wear out faster. As the dimmer begins to wear out, it may generate a constant audible humming sound and even cause radio-frequency interference. 

In this article, we will provide you with adequate information related to whether your dimmers can be left on, and if not, what are the hazards that come with leaving them on. 

Are Dimmers a Fire Hazard if Left on?

When left on for extended periods, dimmers are no more likely to be a fire hazard than when off. Most likely, if you leave the dimmer on low, it won’t cause any problems. However, the fire risk you should consider is the dimmable lightbulb and the fixture. 

If the lightbulb is left on for a long time, it might get really hot due to the heat energy it produces while burning. Such a hot lightbulb can catch fire if it comes into contact with, for example, a piece of cloth, cardboard, paper, etc. So, although it is mostly safe to leave a dimmer on low, it is essential to ensure that the light bulb itself is not surrounded by something that can catch fire. 

Another aspect to keep in mind is that dimmer switches can be a fire hazard if you put too much load on the circuit. A circuit that continuously stays on can happen if the dimmer switches get overloaded by too much voltage. The fixtures attached to these switches might require a larger voltage than what the dimmers are designed to withstand. 

Dimmer switches can get extremely hot and possibly catch fire as well. Therefore, it is advised to check the voltage mentioned on the dimmer switch and the bulb you are attaching to ensure that the dimmer switch will not get overloaded and potentially become a fire hazard.

We also recommend keeping an eye out for any hot-to-the-touch cover plates on the dimmer switches, as this can be a sign of the dimmer having way more energy than it is supposed to be dealing with. Over time, this heat can cause a problem, so it is better to look out for hot switches and fix the reason causing the overheating. 

Also, make sure that the dimmer you use does not have a plastic component, keeping in mind that dimmer switches can get very hot. If there is a plastic component within or around the dimmer switch, it can melt and even cause a fire. Some cheap dimmer switches have plastic pieces instead of metal parts to reduce costs, but this can be a significant fire hazard, and so it is essential to buy a good quality metal-built dimmer. 

Many modern dimmers also have a metal plate, also known as a heat sink. The metal plate allows the switch’s heat to be directed towards the room instead of trapped inside the dimmer. If the heat remained within the dimmer switch, it could potentially damage the switch’s wiring, and these damaged internal wires could easily cause a malfunction of the dimmer switch and cause a fire. 

Hence, it is crucial to choose a high-quality dimmer, which might be slightly more expensive than the common ones available on the market, but keep in mind that the dimmer’s quality and build can protect against fatal situations. So, to leave a dimmer on, the dimmer needs to be built with good-quality components not to pose any risk of fire and be used safely and securely, especially while you’re asleep or away. 

Can You Leave a Dimmer on at Night?

One might want to leave a light on throughout the night in the hallways or living room, for example, which can be quickly done using a dimmer. Dimmers can be easily left on at night and turned off in the morning, as long as the possible risk of fire hazards mentioned above are avoided. Dimmers are available for different light bulbs, and thus you can easily find a dimmer that suits the bulb you wish to attach it with and leave it on at night. 

Dimmers can also save electricity and reduce your power consumption compared to leaving your lights on at night. Dimmers work by reducing the amount of electricity flowing towards the light bulbs, allowing the lights to operate at a lower power level, saving energy in the long run. Leaving a bulb with a dimmer on at night will also help ensure that the light bulb lasts longer as the dimmer can increase its lifespan by reducing its brightness. Since the amount of electricity passing through the bulb is lowered, it will last longer before burning out. 

Although to leave a dimmer on through the night safely, it is necessary to ensure that the dimmer you have is good quality and will not act as a safety hazard. Cheaply made dimmers can get extremely hot, damage the light bulb attached to them, and be at risk of catching fire and burning out. So, as long as the dimmer you are leaving on at night is of decent quality, it is perfectly alright to leave it on. 

Which Bulbs Can Be Left on Constantly?

If you are planning to leave light bulbs on constantly, we recommend using energy-saving or energy-efficient light bulbs because these will conserve the most energy while also fulfilling their purpose. Leaving regular light bulbs on for an extended time can increase your electricity bill for the month and lead to the bulbs having a shorter lifespan due to the constant energy supply, resulting in replacing your bulbs very frequently. 

One of the most commonly used light bulbs that are extremely popular due to their energy-efficient nature is LED. LED stands for Light-Emitting Diodes, and these may be the best option if you wish to leave a light on continuously. Aside from their benefit of being cost-effective and relatively cheaper when left on for a long time, LEDs use very little energy. 

LEDs do not get overly hot and emit less heat energy when turned on. So, you can leave LED lights on for a long time without posing any fire hazards. Another significant benefit of using LEDs to be left on constantly is that they are long-lasting even when they remain turned on for a more extended period, so you will not need to replace your light bulbs every few weeks or months. 

LEDs are very commonly available in the market, and they also come with standard bases that can fit onto almost every light fixture you may have around your house. So, LEDs can be an excellent option for anyone looking to leave the light on constantly. 

Can You Leave Dimmers on Low Constantly? Now You Know

Dimmers are a great way to conserve energy, increase the lifespan of light bulbs, reduce their brightness, scare away possible burglars while you’re away from home, and, overall, can be a great addition to the electrical system within your home.

Dimmers can be a great option if you wish to leave them on always, as they can help conserve energy while being left on for a long time. However, it is essential to take all the necessary safety precautions to avoid a potential fire hazard. It is crucial to connect only dimmable bulbs to a dimmer and ensure that the switch does not get too hot after being left on for a while. It would be best if you also were cautious about the kinds of objects you surround the dimmer to prevent a possible fire.


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.