Are Fairy Lights Safe to Leave on and Will They Catch Fire?

Are Fairy Lights Dangerous?

We all have them, we all love to use them as decoration and we all love to see them shine brightly during the holidays. They are fairy lights, or – as they are more commonly called – Christmas lights and today’s article is going to be about them. The main concerns regarding the fairy lights are their safety and how dangerous they can be.

In general, fairy lights are safe and shouldn’t catch fire. However, there is still a very small chance that fairy lights can overload a socket and start a fire. So, it is crucial to turn fairy lights off if you are going to sleep or leaving your house.

In the text below, we will walk you through how to make sure that doesn’t happen. We know it’s not Christmas, so this article is not going to be about the aesthetic aspects of Christmas lights, but rather about their technical and security aspects.

We are going to answer some burning questions about fairy lights so that you know how to use them properly and how to reduce the risks that come with their usage. Keep reading to find out more!

What Are Fairy Lights?

Fairy lights (also known as string lights and Christmas lights) are small lights often used for decoration in celebration of Christmas and usually on (public) display during the holiday season around the globe. The custom of holiday lights goes back to when Christmas trees were decorated with candles, which symbolized Christ being the light of the world. 

This custom was actually borrowed from pagan yule rituals (not Christian tradition), that celebrate the return of sunlight as the days grow longer after solstice; the evergreen trees symbolizing the renewal and continuance of life in dark times.

The Christmas trees were brought by Christians into their homes in early modern Germany, after which the tradition spread throughout the Christian community and then around the world. 

Christmas trees displayed publicly and illuminated with electric lights became popular in the early 20th century. By the mid-20th century, it became a tradition to display strings of electric lights along streets and on buildings; Christmas decorations thus became detached from the Christmas tree itself and became an aesthetic category.

By the late 20th century, the custom had also been adopted in other nations, including outside the Western world, notably in Japan and Hong Kong.

The Technology of Fairy Lights

The technology used in fairy lighting displays is highly diverse, ranging from simple light strands – the so-called Christmas lights (a.k.a. Fairy lights) – to full-blown animated tableaux, involving complex illuminated animatronics and statues; this is a highly complex electrical installation that requires a lot of sophisticated planning. 

Fairy lights (which are also called twinkle lights, holiday lights, mini lights, or Christmas lights) are actually strands of electric lights used to decorate homes, public/commercial buildings, and Christmas trees during the holiday season; they are amongst the well-known forms of Christmas lighting around the world.

Fairy lights come in a large plethora of configurations and colours. The small, so-called “midget” bulbs commonly known as fairy lights are also called Italian lights in some parts of the U.S., such as Chicago.

The types of lamps used in fairy lighting also vary considerably, which is a general reflection of the diversity of modern lighting technology. Common lamp types are incandescent light bulbs and now light-emitting diodes (LEDs), which are being increasingly encouraged as being more energy-efficient. Less common are neon lamp sets. Fluorescent lamp sets were produced for a limited time in the mid-1940s. 

Fairy lights using incandescent bulbs are somewhat notorious for being difficult to troubleshoot and repair, which why their usage is decreasing in modern times, although they’re still present. In the 1950s and 1960s, the series circuit connected light sets would go completely dark when a single bulb failed.

So in the fairly recent past, the mini-lights have come with shunts to allow a set to continue to operate with a burned-out bulb. However, if there are multiple bulb failures or a shunt is bad, the string can still fail. There are two basic ways to troubleshoot this: a one by one replacement with a known good bulb, or by using a test light to find out where the voltage gets interrupted. 

When Christmas light manufacturers first started using LEDs, the different colours seemed very dull and uninspiring compared to the older models with bright colours. Even the white lights, which were typically single-chip LEDs, glowed with a faintly yellowish colour that made them look cheap and unattractive. This has been remedied in recent years. 

Are Fairy Lights a Safety Hazard?

Well, generally speaking – fairy lights aren’t perceived as a security hazard, although we cannot clearly state that they are fully and completely safe. Generally, they don’t use that much electricity and are not designed in a way to cause any serious trouble. They don’t need a lot of energy to work, which is why they are relatively safe compared to other electronic devices.

What you need to watch out for here is not to overload your socket, meaning that you need to try and connect your fairy lights in a socket where they are going to be the only connected electrical device. Like every device, even fairy lights could cause a short circuit or give you a shock, but that is not overly probable, albeit not completely impossible. 

When this aspect is concerned, you should watch out for faulty installations and/or wires, which could also increase the risk of problems with fairy lights. But if you have good wiring and a socket you haven’t overloaded, the general risk of electrical issues is very, very small. 

As far as heat goes, fairy lights aren’t generally a fire hazard. They don’t use much energy – especially the never, LED models – and they don’t produce much heat. But this is still far from stating that they could not – under any circumstances – cause a fire.

Fairy lights are generally not a fire hazard, but if you leave them in specific conditions (crammed spaces, spaces with an extra heat source, spaces that contain heat well, near something that is very easily flammable), even they might cause a fire and do some serious damage.

This is why it is advised to watch out where you place your fairy lights and also next to what you place it. An important thing here is to reduce their usage.

Namely, although they can – theoretically – be turned on during the whole day, it is not advised to do that, to increase their longevity and also to reduce the risk of increased heat and/or electrical damage. Electronic devices aren’t meant to be on 24/7, so it’s advised to use them reasonably, despite the fact that they could – generally – run all the time. 

Can You Put Fairy Lights on Fabrics and Other Similar Material?

Generally – yes. Fairy lights aren’t a big fire hazard to it is, generally, safe to put them on different fabrics (like curtains, clothes, etc.), wood, and even trees, i.e., materials that are generally considered to be flammable.

If you keep in mind everything we’ve said in the preceding chapter, you should be safe. But, if you don’t follow the instructions and if you actually increase the risks by abusing your lights, it is not advised to keep them near some flammable material or substance. 

Can You Leave Plug in Fairy Lights on All Night?

As we’ve stated before, there is a small chance that fairy lights can put on a fire, but, there is still a chance. Even if your fairy lights meet a certain quality standard and you make sure that they don’t overload a socket, it is completely advised not to leave your fairy lights plugged in all night (or even if you are going out of your house).

If you have your fairy lights on a Christmas tree, there is an even bigger chance for a fire (because a tree can be dry, thus a very good match for a fire). To conclude, even though there is a small chance for fairy lights to start a fire, a chance is still there. So, be absolutely sure that you plug off fairy lights if you are going to sleep or out of the apartment.

Types of Fairy Lights

Now that we’ve shown you the basics and the main security issues, let us briefly go through the types of lights used in modern fairy lights:

Incandescent light bulb

Incandescent light bulbs have been the most common bulbs used in fairy lights until recently. These lights produce a broad-spectrum white light and are coloured by coating the glass envelope with a translucent paint which acts as a colour filter. Some early Japanese-made lamps used coloured glass.

Light-emitting diodes (LED)

Light-emitting diodes (LED) are becoming the most popular sources of fairy lights due to their low energy usage, long lifetime, and associated low maintenance. Coloured LEDs are far more efficient at producing light than their coloured incandescent counterparts.

There are two types of LEDs: coloured LEDs and white LEDs. Coloured LEDs emit a specific colour light (monochromatic light), regardless of the colour of the transparent plastic lens that encases the LED’s chip. The plastic may be coloured for cosmetic reasons but does not substantially affect the colour of the light emitted.

Holiday lights of this type do not suffer from colour fading because the light is determined by the LED’s chip rather than the plastic lens.

Fiber optic technology

Fiber optic technology is also used in modern fairy lights, especially by incorporating it into artificial Christmas trees. Incandescent lamps or LEDs are located in the tree base and many optic fibers extend from the lamps to the ends of the tree branches.

Bubble lights

Bubble lights are a type of incandescent novelty light that acquired some popularity during the 1950s. Their main feature is a sealed glass tube with a colored bubbling liquid inside, created by the heat from the incandescent light.

The fluid within the vial was originally a lightweight oil, but now is methylene chloride for a more consistent bubble effect. While the idea was first demonstrated by Benjamin Franklin, the idea was adapted for use in Christmas lights. They were invented by Carl Otis in 1935. There is a long story involving patent fights. Bubble lights can still be purchased online and in stores to this day.

Laser projector systems

Laser projector systems became a prominent phenomenon in 2015; the devices are typically installed on a stake in front of a house, projecting colored dots resembling stars. The devices are marketed as being safer and easier to install than traditional string lights.

The concept was popularized by the Telebrands company, which launched a brand of low-cost laser projectors known as Star Shower Laser Light in July 2015. Star Shower saw considerably high demand, with stores quickly running out of stock, and reports of the devices being stolen right out of front yards. In 2016, Star Shower introduced an updated version of their product with motion effects.

This covers our analysis of the topic for today. For more information, keep following us and stay tuned for more of the same.


  • Tristan

    Tristan has a strong interest in the intersection of artificial intelligence and creative expression. He has a background in computer science, and he enjoys exploring the ways in which AI can enhance and augment human creativity. In his writing, he often delves into the ways in which AI is being used to generate original works of fiction and poetry, as well as to analyze and understand patterns in existing texts.