Fog Machines 101: A Beginner’s Guide

Fog Machines 101: A Beginner's Guide

Irrespective of the amount of decorating your next concert or Halloween haunt will involve, there is one crucial mood-setting detail that will set your spook alley or yard apart from the rest. I will not keep you guessing.

If you want to create the spookiest Halloween mood or spruce up your concert stage, a simple element that can achieve this goal is creating some dense fog. Fog can not only make a huge difference, but it is also easy to generate.

What Is A Fog Machine?

A fog machine also called a smoke machine, or fog generator is a device used to emit a dense or opaque vapor quite similar to smoke or fog. Artificial fog or smoke has long been a part of a variety of professional entertainment applications; however, smaller and more economical fog machines are increasing in popularity for personal use.

Fog Machine

There are plenty of training, industrial and military applications for fog machines as well. Moreover, a lot of warehouse and production units have these devices installed to keep out bugs and to regulate humidity.

In most cases, fog is created through vaporization of water and glycerin-based or glycol-based fluids or via atomization of mineral oils. This liquid (often known colloquially as fog juice) atomizes or vaporizes in the fog machine. On exiting the fog machine, the vapor mixes with colder outside air and condenses, creating a thick visible fog.

There are several ways of creating a unique ambiance or mood for different kinds of events you might be having. A fog machine is a great and simple way to produce fog or mist in the air, enhancing all types of affairs, from haunted houses and Halloween parties to theatrical productions, rock concerts, and dance parties.

Fog machines are available in different sizes and have varied levels of mist or fog output. The kind of fog machine that best meets your needs will depend on the size of the area that you want to make foggy.

How Fog Machines Work

A fog machine is not a very complicated machine. Essentially the device is designed to pump fog juice or fog liquid from a reservoir to a heat exchanger. Then the fluid is heated and turns into vapor.

In most cases, there are five parts in a fog machine which make it work. These are the heat exchanger, pump, nozzle, fog machine fluid and remote control (found on most models).

The fog juice or fluid goes into the reservoir. It is forced via a heat exchanger using a high-pressure pump.  Heat exchangers on most fog machines can heat up to 450 degrees Fahrenheit.

That turns the fluid into a vapor. The vapor moves through the fog machine's nozzle and out into the atmosphere. As soon as the gas makes contact with the colder air outside, it condenses into fog or smoke.

A piston or pressure pump delivers the fog juice or liquid from the reservoir to the heat exchanger. In case you hear any sound during the operation of a fog machine, it is usually the pump working.

How Fog Machine Work

A heat exchanger is a metal block that has a heating mechanism built inside. A thermostat regulates the temperature inside. The heated liquid travels to the machine’s nozzle in vapor form.

If you compare different models of fog machines, you will notice the term “watts." Fog machines with higher wattages can produce more fog.  That is why it is crucial you go for a top wattage machine as it will have fewer re-heat cycles because of the sturdiness of the heat exchanger.

The nozzle of a fog machine is usually brass. It has a tiny opening or hole that emits vapor under pressure.

During operation, both the opening and nozzle can become extremely hot. Therefore, do not place anything flammable near it or touch it. A majority of modern fog machines come with remote controls. The remote has a single button and operation is very simple.

All you have to do is hold down this button to release mist and stop the fog by releasing the button. A remote control with an automatic timer is a great option. You can set the timer and control when and how much fog comes out along with the duration of the release.

Types Of Fog Machine

There are many types of fog machines available on the market with different wattages, sizes, warm up times, and output. We will consider the main types of fog machines.

Heated Fog Machines

A heated fog machine uses either an electric pump or inert gas to propel a mixture of glycol, or glycerin, mineral oil and water into a heat exchanger. The mixture vaporizes in the heat exchanger.

The pump machine is the most commonly used type of heated fog machine. The most basic version of a pump machine comes with a liquid reservoir and has an electric pump that moves the liquid and a heat exchanger to vaporize the liquid.

On the other hand, sophisticated models often have many different features, such as a variable speed pump that controls the fog output, timer module or components for remote monitoring and operation of the fog machine.

A few manufacturers produce fluids and other accessories that when used with a standard heated pump machine develop fog or mist effects very similar to those created by chilled fog machines.

Heated Fog Machine

A gas-propelled fog machine uses an inert gas (mostly nitrogen or CO2) to drive either glycol-based fluids or mineral oil into the heat exchanger vaporizing it into particles, which creates a fog. Some models of modern gas-propelled fog machines offer control over fog output by changing the gas volume.

Chilled Fog Machines

A refrigerated fog machine is designed to generate thick, opaque fog clouds that stay close to the floor and slowly dissipate while rising. The shadows of the fog are usually created using liquid nitrogen, dry ice or recently moist air. Dry Ice effects are produced by slowly heating water until it reaches the boiling point.

A suitably large container is used for this purpose (for instance: a 50-gallon drum with heating coils inside). Then a couple of pieces of dry ice are placed inside. As carbon dioxide is in a gaseous state at standard pressure and temperature, the ice sublimates instantly and produces gas.

The condensation of water vapor creates a thick white fog. One or more fans placed at the top of the water container direct this fog where it is required. In many cases, liquid nitrogen is used to generate a low-lying fog or mist effects in a way quite similar to dry ice.

For this purpose, a machine is used to heat water to the boiling point, producing steam and raising the humidity level in a closed container. As soon as nitrogen pumps into the water container, the moisture quickly condenses and creates a thick and white fog.

Fans are used to direct the mist where needed. That often creates a rolling fog that tends to lie close to the ground.

Moreover, liquid air can be used as an alternative to liquid nitrogen to generate the low-lying fog effect, which looks spectacular. The moist atmosphere from the fog machine around you is made up of nitrogen and oxygen combined in a precise ratio of 21% oxygen and 79% nitrogen. The liquid rests in an insulated cylinder.

The rate of oxygen to nitrogen is the same as found in atmospheric air. Liquid air is fabricated by the process of liquefaction. Atmospheric air is compressed, cooled and expanded - this process repeats until the air becomes a liquid.

The main advantage of using liquid air instead of liquid nitrogen is it poses no asphyxiation risk, as it has oxygen in it. However there is also a downside; moist air supports combustion, while liquid nitrogen restricts it.

Haze Machines

A haze machine also called a haze generator, or just a hazer is designed to create homogeneous and unobtrusive clouds in the air. The device mainly helps make the light beams visible or produce a subtle diffusion. Different from a theatrical fog that is often intended to be opaque or dense, haze is usually quite delicate and light.

Fury Faze 700-Watt Machine

These unique properties of haze allow a venue, such as a concert stage, to be filled with it before or during the event without having to create an overtly distracting fog cloud. Also, haze has a considerably longer persistence compared to traditional theatrical fog.

A conventional fog would stay suspended in the air for only a few minutes, while a typical haze effect used in the same space volume could last from one hour to several hours. The exact duration will depend on the venue size and amount of ventilation.

Fluids used in a haze machine to create the effects are water or oil-based. A majority of oil-based liquids use mineral oil bases; on the other hand, water-based fluids tend to use a glycerol or propylene glycol base. While both fluid formulations are known as haze fluid, keep in mind the different fluid formulations are neither interchangeable nor compatible. 

Propylene water/glycol haze solution is sometimes called "water-based haze" to avoid confusion or ambiguity. Describing this solution as "glycol" may cause stagehands or other professionals to use antifreeze, which often contains ethylene glycol and you should not use it for this specific purpose.

Uses Of Fog Machines

Fog machines are used extensively in concerts, theaters and for various industrial purposes.


Fog machines are used in shows and help create a specific feeling or mood for different theatrical moments. They are also used in a variety of plays like A Christmas Carol, Dracula, and MacBeth. Halloween is the perfect occasion to whip out a fog machine and decorate the place with an eerie or mystifying display. 

Due to their reduction in price and higher widespread availability beginning primarily between 2003 and 2005, fog machines are now commonly used for household Halloween presentations. Theatrical fog and smoke are indispensable if you want to create different types of visible and mid-air laser effects to keep your audiences entertained.

Liquid carbon dioxide, (usually kept in compressed cylinders), is often used in combination with fog machines to create a "low-lying" fog effect in theatrical performances. You can use the fog machine to create a dense, thick fog that hovers within a couple of feet of the floor. As this mist slowly warms or agitates, it starts rising and dissipating.

Theatrical Smoke

A lot of theatrical fog fluid manufacturers have recently created specially formulated mixtures that can mix with carbon dioxide. They provide more consistent and thicker fog effects. The duration of the fog effect usually depends on the heating cycle of fog machines as well as the consumption rate of carbon dioxide.


Fog machines are popular in music concerts. Many bands maintain their own sound systems, fog machines, and even lights. According to many musicians, fog is essential. Also, if a group only has a fog machine, it can do the trick as a majority of venues and clubs have lights. Fog is perfect if you are looking to create the right atmosphere or ambiance for a musical performance.

Many musicians also prefer buying scented fog because the crowd tends to enjoy it more compared to standard unscented mist. There are different versions of scented fog such as vanilla and musk.  If you are at an entertainment venue, such as a concert stage, and see beams of light cutting across a room, it most likely indicates fog or smoke.


Due to the refractive and reflective qualities of the fog produced by many fog machines, they are extensively used in many nightclubs and various other entertainment sites to improve or augment the effects of laser and lighting arrangements. Haze machines are the most widely used type of fog machine in nightclubs.

Industrial Uses

Fog machines have also become prevalent in various industrial applications other than the entertainment industry. That is because fog machines are easy to use, rugged and portable. A few favorite applications of fog machines include environmental testing (like HVAC inspections) and disaster response and emergency personnel training exercises.

Cleaning companies use ultra-low volume fog machines for pest control. They have a small droplet size, which is optimum for pest control. Cold fogging, in particular, is sufficiently dense and can penetrate inaccessible areas.

Several organizations in Canada and Europe have developed a rapid deployment fog machine. These machines are used as hold-up and intrusion security systems and can disorient an intruder easily by filling a space with fog if an alarm is triggered using the panic button on a security device.

Exercise With Fog Machine

These fog machines can generate up to a thousand cubic meters of fog in just 30 seconds in a broad range of industries, including buildings that need a higher level of security, like jewelry shops and banks, but also offices, warehouses, and retail premises.

Is It Dangerous To Inhale Clouds Of Fog From A Fog Machine?

Atmospheric effects created with dry ice and water or liquid nitrogen may lead to asphyxiation or breathing problems. As both nitrogen and carbon dioxide can displace atmospheric air including the oxygen, they pose a risk of anoxia (commonly known as lack of oxygenation) for individuals in these atmospheres.

As a result, proper ventilation is necessary to make sure healthy, breathable air surrounds technicians and artists. Besides, carbon dioxide used in fog machines has the additional risk of meddling with a person's normal breathing reflex that is quite sensitive to the level of carbon dioxide present in the air.

Although nitrogen does not have any adverse effect on your breathing reflex, it poses its own risk in that people inhaling pure nitrogen could easily lose consciousness due to the lack of oxygen in the air without showing any warning signs. On the other hand, fog created with pure liquid air does not carry the same risk as liquid nitrogen or carbon dioxide. That is because moist air has a similar composition as standard atmospheric air.

A majority of fog machines that produce their effects using only water, like pressurized or ultrasonic technology, often do not pose any health risks. However, always keep in mind that "water-based" smoke or fog fluid contains glycol. Exposure to glycol smoke or fog can cause nausea and dizziness, headaches, tiredness and drowsiness in the short term.

On the other hand, long-term exposure to glycol smoke or fog can lead to voice and upper airway symptoms. Finally, extended exposure, lasting over several years, to fog and smoke can cause both long-term and short-term respiratory health issues.

You should make the effort required to lower exposure, especially to theatrical fog or smoke.

What Is Fog Juice?

Fog machines generate a dense and thick vapor that is similar to smoke or fog. They vaporize a solution called fog juice and pump this gas into the open air. As soon as the mist comes in contact with moisture present in the air, the vapor condenses and forms a thick fog.

Medium Fog Juice

It is dangerous to mix fog juice at home; however, you could safely produce specific types of fog juices that use water and glycerin.

DIY Fog Juice

You should always use distilled water for making all types of fog juices at home as ordinary water can clog your fog machine with its mineral deposits. Buy glycerin, which you can safely mix at home. Fog machine fluids made using glycerin will produce haze or light fog, rather than the dense, rolling fog used by nightclubs.

Choose a suitable mix of glycerin and distilled water for the desired effect. A five percent mixture of glycerin will generate a light haze, while a ten percent mixture will create a medium fog and so on.

Dispense a suitable amount of glycerin in a plastic container and then add the required quantity of distilled water. Then close or seal the container and vigorously shake it to ensure the ingredients mix.

Will A Fog Machine Set Off A Fire Alarm?

The answer to this depends on the type of smoke detector. It is likely that small water-based particles in high concentration may set off some kinds of smoke detectors. This problem is mostly encountered with optical sensors, as they treat these water particles like smoke.

Maintenance Tips

Regular maintenance of a fog machine is essential for its longevity. Follow these tips to clean and maintain your fog machine.

  • Turn off your fog machine. When it has cooled, empty the contents of the fluid reservoir
  • Rinse the fluid tank thoroughly using distilled water
  • Now pour a solution of white vinegar (1/3) and distilled water (2/3) into the reservoir
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    Turn on your machine and heat it up and then run it for four to six bursts
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    Now turn the machine off and empty the mixture from the fluid reservoir
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    Rinse the fluid reservoir again using distilled water
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    Always keep the fog machine filled with some fog fluid in a climate controlled environment on a flat surface. That helps neutralize any acid in the lines


We have discussed what a fog machine is and how it works. We have looked at the different types of fog machines such as heated fog machines and haze machines. We have also looked at the various uses of fog machines such as in theaters, nightclubs, concerts and industrial applications.

Using Fog Machine On Wedding

We have also discussed why inhaling fog clouds can be detrimental to your health. We have explained what fog juice is and how you can prepare it at home. We have highlighted why some types of fog machines can trigger smoke or fire alarms.

Finally, we have provided some useful tips to maintain your fog machine. Our buying guide will discuss the different features that you should consider when buying a fog machine along with some recommendations.

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