The safe way to add scent to a fog machine is to use fog fluid that is already scented, or a scent additive made by your fluid’s maker for that fluid. Never put essential oils, perfume or fragrance oils into a heater-based fog machine.
Oils don’t mix with water-based fog fluid, and they can scorch on the heater, clog the machine and void your warranty. If you want a stronger smell, the easy fix is to scent the room separately, and this guide shows you how.
Why Oils and Perfume Don’t Belong in a Fog Machine
Most party and Halloween fog machines are heater-based. A small pump pushes water-based fog fluid (distilled water mixed with glycol or glycerin) through a hot heat exchanger, which turns it into fog.
Essential oils and fragrance oils don’t dissolve in that fluid, so they float and reach the heater in concentrated drops. There they can burn, leave sticky residue and clog the heat exchanger or nozzle.
Perfume, body spray and many room sprays contain alcohol, which is flammable. Nothing flammable should ever go near a fog machine heater.
Fog machine makers such as Chauvet and ADJ tell you to use only fluid approved for your machine, and the wrong fluid can void the warranty. Check your machine’s manual before you put anything new in the tank.
| Scent option | Safe to use? |
|---|---|
| Pre-scented fog fluid made for your type of machine | Yes |
| Scent additive made for your brand of fog fluid | Yes, at the maker’s dose |
| Essential oils in the fog fluid | Never |
| Perfume, body spray or other alcohol-based fragrance | Never (flammable) |
| Fragrance oils, candle oils or scented baby oil | Never |
| Plug-in, reed or ultrasonic diffuser elsewhere in the room | Yes, kept away from the machine |
Know Your Machine Type First
Before buying scented fluid, check whether you have a water-based fog machine, a water-based hazer or an oil-based hazer. The manual or the label near the fluid tank will tell you which fluid it takes.
Water-based fog machines and hazers use glycol or glycerin fluids. Oil-based hazers use a special mineral-oil haze fluid, and only the fluid their maker specifies.
Never mix water-based and oil-based fluids, and don’t put haze fluid in a fog machine unless the manual says it’s made for it. If your manual tells you to flush the machine with water, use distilled water, never tap water.
Option 1: Use Pre-Scented Fog Fluid
The simplest way to get scented fog is to buy fog fluid that already has scent in it. Several fog-fluid makers sell scented fluids for water-based fog machines, often in seasonal scents for Halloween and parties.
Pick one that is labeled for your type of machine, and fill the tank the way your manual says. Don’t mix brands or top up scented fluid with a different fluid.
Expect a light scent, not a strong one. The smell fades as the fog clears, so for a big room you may want to add a room diffuser too (see Option 3).
Option 2: Use a Scent Additive Made for Your Fog Fluid
Some fog-fluid makers sell concentrated scents designed to be mixed into their own fluid. If you go this route, use only an additive made for your brand of fluid and add exactly the amount on the label.
Don’t add extra for a stronger smell, because too much can leave residue in the machine. If a product doesn’t say it is made for fog machines, it doesn’t go in the tank.
Option 3: Scent the Room, Not the Machine
You can keep your fog machine on plain fog fluid and add scent to the room separately. This gives you more scent choices and keeps oils away from the heater.
- A plug-in or reed diffuser placed where the air moves across the fog.
- An ultrasonic essential oil diffuser (cool mist, no heat) set a few feet away from the fog machine.
- A small fan behind the scent source to push the smell along the same path as the fog.
Keep any scent source a few feet from the fog machine and well away from its outlet. Skip candles and other open flames near the fog, since people can’t see them well once the room fills up.
If pets will be in the room, be careful with essential oils. The ASPCA warns that many oils, including tea tree, peppermint, eucalyptus and citrus oils, can be toxic to cats and dogs, and birds are especially sensitive to anything in the air.
If you want a diffuser that doubles as decor, see our picks for the best flame essential oil diffuser.
Safety Tips for Scented Fog
- Never add anything flammable to a fog machine: no perfume, alcohol, essential oils or other oils.
- Ventilate the room. Scent and fog can bother people with asthma or fragrance sensitivity, so go light.
- Keep fog away from smoke detectors and use short bursts, but never disable a smoke detector.
- Don’t let the machine run dry, and refill it only with the fluid it is meant for.
For more on breathing fog, see are fog machines safe to breathe?
Cleaning Your Machine After Scented Fluid
Scented fluid can leave its smell in the tank and lines, so clean the machine before you switch back to plain fluid or put it away. Run a cleaning cycle with the maker’s fog machine cleaner, or flush with distilled water if your manual allows it.
Then empty the tank and let the machine dry before storage. Our guides on how to clean a fog machine and how to store a fog machine cover the full steps.
Keep scented fluid in its original bottle, tightly capped, away from heat and sunlight.
Troubleshooting Scented Fog
Scent too weak: This is normal with scented fluid. Add a room diffuser instead of adding more scent to the tank.
Burning smell, smoke or spitting: Turn the machine off, unplug it and let it cool. This usually means the wrong fluid or something added to it, so drain the tank and clean it per the manual before you run it again.
Weak fog after switching fluids: Old fluid may still be in the lines. Run a few short bursts with the new fluid, or clean the machine per the manual.
Frequently Asked Questions
Can I put essential oils in my fog machine?
No. Essential oils don’t mix with water-based fog fluid and can burn on the heater, clog the machine and void your warranty. Use scented fog fluid instead, or run a diffuser elsewhere in the room.
Can I put perfume in a fog machine?
No. Most perfumes and body sprays contain alcohol, which is flammable, so they should never go into a heated machine.
How long does the scent from scented fog last?
It depends on the fluid, the size of the room and how much air moves through it. In most cases the scent fades soon after the fog clears.
Will scented fog leave residue on furniture?
Any fog fluid can leave a light film near the machine with heavy use, scented or not. Keep the machine back from furniture and avoid heavy fog over hard floors people walk on, since the film can make them slippery.
Is scented fog safe around pets?
Keep pets out of heavy fog and ventilate the room. Never put essential oils in the machine, and keep any diffusers out of pets’ reach, since many oils are toxic to cats and dogs.
Conclusion
To add scent to a fog machine, use pre-scented fog fluid or an additive made for your fluid, and follow the maker’s directions. Never put essential oils, perfume or fragrance oils into a heater-based fog machine.
For a stronger smell, scent the room separately with a diffuser placed away from the machine. Clean the machine after using scented fluid, and check your manual whenever you’re unsure.
