Smoke, Fog, and Haze Machines - What’s the Difference?
Atmospheric Effects Machines
Atmospheric effects are integral to creating immersive environments in various settings, from clubs and concerts to mobile DJ work and home parties. Among the most commonly used machines for these effects are Smoke, Fog, and Haze machines.
Each type of smoke-producing machine produces distinct results suitable for different applications. In this guide, we’ll delve into the specifics of each machine, their uses, and how to choose the right one for your needs.
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Smoke Machines
Smoke machines generate dense clouds of smoke by heating water with a glycol or glycerin-based additive. The vaporised fluid is expelled through a nozzle under pressure to create a thick, opaque smoke that fills a space rapidly. These machines are popular for creating dramatic, fun atmospheres, making them a staple at Halloween events, theatrical productions, and concerts where a pronounced visual effect is desired.
One notable feature of smoke machines is their ability to produce large volumes of smoke quickly, which can temporarily obscure visibility and create a sense of mystery or suspense. Their vast output means that even smaller budget smoke machines can fill a small to medium-sized room quickly, making them an inexpensive effect that will enhance your lighting and atmosphere.
Rated by the wattage of their heating elements, smoke machines usually start at 500W for a compact party machine and increase in power rating up to around 2500W, with a matched increase in smoke production to suit different requirements.
However, the density of smoke they produce can also be a drawback in settings where a lighter effect is required and visibility is important. Additionally, smoke machines may trigger smoke alarms (depending on the type), necessitating testing and planning for use in some venues.
Fog Machines
A standard fog machine is exactly the same as a smoke machine. The name is interchangeable (UK always used smoke, USA used fog), so either can be used to describe what is a normal smoke machine.
Where fog machines do differ is in the variant models, which are known as ice-foggers and low-lying fog machines. These units operate similarly to smoke machines but are used to create a floor-hugging fog that emulates the classic effect of dry ice. This is achieved in ice-foggers by the inclusion of a cool box storing ice cubes, which the smoke vapour is blown over before it exits the machine. This drop in temperature helps the smoke lay below the warmer air in the room.
The larger low-lying fog systems use a system of ultrasonic vibrations and a mixture of chilled distilled water and smoke fluid to produce a large volume of smoke that is distributed via a long output hose for large area coverage. The fog will stay at floor level until it warms, and will then disperse into the room.
The primary difference between these low fog systems and smoke machines lies in the fog's density and behaviour. Fog machines produce a less dense effect than smoke machines and can be controlled to create various atmospheric conditions. They will still fill a room, but their primary design is for their dry ice-style ground effect rather than the overall atmosphere or lighting enhancement.
Haze Machines and Faze Machines
Haze machines, or hazers, use either water or oil-based fluids to produce a fine, room-filling mist rather than dense smoke or fog. This mist is less visible to the naked eye but is excellent for enhancing lighting effects while retaining visibility It’s for this reason that haze machines are the most used atmospherics in concerts, theatres, and events where lighting plays a key role, as the fine particles they release catch and reflect light beams, adding depth and dimension without significantly reducing visibility.
Lower-cost haze machines will be water-based, using a standard fog fluid but at a lower heat than a smoke machine and output via a horizontal slot rather than a nozzle to further aid dispersion. They are safer for smaller venues and indoor use as the mist does not leave any residue on surfaces. A faze machine or ‘fazer’ is a variant of the haze machine and includes the addition of an air pump that enhances the atomisation which allows for a much smoother and less cloudy output.
Professional haze machines will be mineral oil-based. They produce a much finer and uniform mist by pushing the oil through a compressor which atomises it with high-pressure air. It’s a mechanical process so doesn't require heating like the water-based types. It's what's known as a particle effect, filling the air with fine droplets that will reflect light. However, it leaves a thin oil residue on surfaces after long exposure, so it tends to be used only in environments that have good ventilation and will be cleaned regularly. (a non-residue oil is now available but does not suit all machines).
The output created by oil haze machines stays suspended in the air for much longer durations (hours rather than minutes), providing a continuous atmospheric effect ideal for enhancing light shows and creating an immersive environment.
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Delving Deeper: Smoke, Haze, and Fog Effects
Understanding the intricacies of smoke, fog, and haze machines helps in making an informed choice for your specific needs. Let's explore various options, features, and common questions surrounding these machines.
Fluid Types and Their Effects
Smoke and Fog Fluids: Modern smoke and fog machines typically use water with a glycol or glycerin-based additive, very similar to the PG/VG formula that's used in vape fluid. Syphoned by an electric pump from a fluid reservoir and forced into a heat exchanger, the smoke fluid vaporises to create thick clouds of smoke or fog. There are different formulations of these fluids, each producing varying densities of smoke and a variable dispersion rate in the air (known as hang-time.
Water Haze Fluid: Water-based haze fluids are safer and leave no residue, making them ideal for indoor events. The formulas are usually 98% distilled water, with food-grade glycol or glycerin added to create the required density and visual ‘fog’ effect during the heating process (otherwise it would just be steam).
Oil Haze Fluid: Traditional haze fluid is made from mineral oil, which is a heavily refined petroleum product. It is extremely economical in use as it can take hours to dissipate, compared to water-based haze which has a hang time of just a few minutes, meaning the machine is in constant use to maintain the effect.
Traditionally it would leave a thin oil residue on surfaces after extended use, though modern oil formulas now features additives that dry it on surface contact.
Common Questions and Considerations
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Is smoke from smoke machines harmful?
Smoke produced by these machines can contain small particles that may cause irritation for some individuals, especially those with respiratory conditions. Water-based fluids are considered safe are completely non-toxic formulations, but it’s advisable to ensure good ventilation when using any type of atmospheric effect machine.
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Can a fog machine trigger a smoke alarm?
Yes, both fog and smoke machines can trigger smoke alarms due to the particles they release. It doesn't affect all alarms, it just depends if they are ionisation or optical detectors, so It’s advisable to test the machine in your venue to see if its a problem.
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How long can you leave a smoke machine on?
Smoke machines can be left on for extended periods, but they usually have duty cycles, requiring a pause to reheat the fluid. Budget models can also overheat with constant use and their thermostat will need a cool-down period to allow further smoke production. Continuous output models are available for professional use, but they come at a higher cost.
This is true of all heater and pump-based machines, so smoke, fog and water haze units. Oil-based hazers are the exception to this as they are a compressor-driven design which doesn't require heating, so will run indefinitely.
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Is it okay to use a fog machine in the house?
Using a fog machine indoors is generally safe, provided you use the correct fluid and ensure proper ventilation. The water-based fluid is non-toxic and safe to breathe. Avoid oil-based fluids in enclosed spaces as they can leave a residue and make floors slippery.
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Do smoke machines leave a residue?
Yes, especially if oil-based fluids are used. Water-based fluids are less likely to leave a residue, making them more suitable for indoor use, though heavy usage can leave a fine film to surfaces.
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Can you colour smoke from a smoke machine?
An often asked question, and one that’s not helped with companies colouring their smoke fluid, which leads to the assumption that the smoke produced will be coloured. Smoke, fog, and haze machines can only produce standard white/grey smoke, regardless of any colouring the fluid may have in the bottle. You can't create coloured smoke with these machines.
If you see coloured smoke at an event it will have been produced by an incendiary device such as a smoke bomb or flare.
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What is the difference between fog liquid and smoke liquid?
While often similar, fog-specific liquids are specifically formulated to create low-lying effects and may include additional chemical components to enhance this property. They also are heated at a lower temperature which decreases the density of the output.
Smoke liquids are designed to create thicker clouds that rise and spread throughout the space. They come in different formulas which have the glycol content tweaked to increase or decrease with the in-air duration (hang time) or the overall fog density.
Special Features and Applications
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Remote Controls and DMX Compatibility:
Many modern machines come with either radio or infrared remote controls, allowing users to trigger the effect from a distance. Advanced models also offer DMX compatibility, integrating with lighting and stage control systems to sync the atmospheric effects with the rest of the show.
Depending on the features of the machine, DMX can offer you the ability to manually adjust burst interval times and firing timers that allow the smoke systems to be timed to light shows or music.
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Built-in LEDs:
Some fog and haze machines now feature built-in LEDs, which can colour the fog or haze as it is emitted eliminating the need for separate lighting fixtures and creating vibrant, multi-coloured effects.
This can be anything from a basic single-colour wash effect to full RGBW multi-colour lights with strobing. The LEDs will often be separately switchable and on units with DMX will be controllable in the same way as any professional effects light unit.
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Maintenance and Cleaning:
Regular maintenance is essential for the longevity of these machines. Prior to heating, the water-based glycol fluid will sit in the tubing and pump and can become a bit gummy if the machine is only used occasionally due to the glycerine forming a sugary type of goop. Smoke and fog machines often need their fluid tanks cleaned and syphon tubes checked to clean any build-up and prevent clogging.
Haze machines using oil-based fluids require less frequent cleaning but should still be monitored to ensure optimal performance.
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Safety Tips:
Always follow the manufacturer’s guidelines for fluid use and machine operation. Always use the correct fluid for your machine, as the pump and heat exchanger will have been designed for that specific viscosity of fluid.
Ensure good ventilation when using any atmospheric machine, and be mindful of individuals with respiratory issues. Testing the equipment in your venue beforehand can help prevent unexpected issues, such as triggering smoke alarms or causing excessive smoke buildup.
For mobile work always make the smoke machine the first thing you unplug at the end of the night. It gives them time to cool down so they can be handled safely as the bodies of the machines get extremely hot during use.
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Select the Right Machine:
Depending on your event, choose the machine that best fits your needs. For instance, use haze machines for subtle lighting effects and smoke machines for dense, dramatic effects.
Be realistic with your expectations. A budget 500W smoke machine is simply not going to be powerful enough for large events, so don't do it to yourself. Professional users should be looking at 1500W machines as a minimum, and these larger machines will have better fluid storage tanks and extra features that allow them to operate trouble-free for extended periods.
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Proper Fluid Selection:
Ensure you use the correct fluid for your machine to avoid damage and achieve the desired effect. Water-based fluids are safer for indoor use, while oil-based fluids provide longer-lasting effects.
Not all effects fluids are the same chemical composition, and using some unknown budget liquid you found online is a fast way to ruin your machine's internals, and risk causing bad health reactions from your audience. Remember, this is something that people are going to be breathing in, so do not cheap out on it. If the manufacturer of your machine makes fluid designed for it then just buy that.
Also, never attempt to modify effects fluid in any way. The ratios are specifically designed to heat the correct way for atomisation. Stories of destroyed fog machines because the fluid was ‘watered down to last longer’ are just crazy. Do it the proper way, or not at all.
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Test Before Use
Always test your machine in the venue to check for any potential issues, such as setting off smoke alarms or causing visibility problems. The smoke alarm question comes up a lot, but its one of those things that differ with every venue, so testing is the only way. It will also show you how the smoke output will cluster or linger which gives you a better idea of optimum placement.
Best Practices for Using Atmospherics
Final Thoughts
By understanding the differences and applications of smoke, fog, and haze machines, you can create the perfect atmospheric effects for your event or production.
Atmospheric mist or fog is part of your lighting system and is essential when using moving head lights, strobes, and laser light systems, which require the airborne particles of the smoke to allow their light output to become properly visible.
Each machine has unique advantages and considerations, making them all indispensable tools for enhancing the visual experience in various settings. It's simply a case of the right tool for the job.