A fogger is a device that turns a liquid into a fine fog or mist of tiny droplets. Whether you have seen a pest-control technician treating a garden, a cleaning crew disinfecting a room, or a cloud of atmospheric fog rolling across a party tent, there is a good chance a fogger was doing the work. In this guide we explain exactly what a fogger is, how it works, the main types available, what people use them for, and how to choose the right one.
What Is a Fogger?
A fogger is a machine that breaks a liquid, such as an insecticide, a disinfectant, or a special fog fluid, into extremely small droplets and disperses them into the air as a visible fog. Because the droplets are so fine, they stay suspended longer and spread into corners, cracks, and open spaces that a spray or wipe would miss. That combination of coverage and reach is what makes foggers so useful across pest control, sanitation, agriculture, and entertainment.
How Does a Fogger Work?
All foggers share the same basic goal, turning liquid into fog, but they do it in two main ways:
- Thermal foggers heat the liquid so it vaporises and instantly condenses into a dense, visible fog when it hits the cooler air. This produces very fine droplets and a thick cloud.
- Cold foggers use air pressure or a fast-spinning mechanism to shear the liquid into droplets, with no heat involved. These are often called ULV (ultra-low volume) foggers.
The size of the droplets, measured in microns, is a key difference. Smaller droplets hang in the air longer and cover more space, while larger droplets settle faster onto surfaces.
Types of Foggers
Thermal foggers
Thermal foggers create a thick, highly visible fog and are popular for outdoor mosquito and insect control over large areas such as gardens, yards, and open events.
Cold foggers (ULV)
Cold or ULV foggers work without heat and are versatile for both indoor and outdoor use. They are widely used for disinfecting, odour control, and applying water-based solutions.
Pest control and insect foggers
This category includes handheld and backpack foggers as well as “total release” foggers, sometimes called bug bombs, which discharge their entire contents to treat a closed room for insects.
Disinfectant and sanitising foggers
These apply disinfectant as a fine mist to cover large surface areas quickly, a method that became especially common for sanitising offices, gyms, and public spaces.
Fog machines for events and entertainment
Event fog machines, the kind used at concerts, parties, festivals, and Oktoberfest-style event tents, are a type of fogger that vaporises a glycol or glycerin-based fluid to create atmospheric haze for lighting and stage effects.
Agricultural and greenhouse foggers
In farming and horticulture, foggers apply pesticides or add humidity and cooling in greenhouses, helping to protect crops and control the growing environment.
Common Uses of Foggers
- Mosquito and insect control in gardens, yards, and outdoor venues.
- Disinfecting and sanitising indoor spaces.
- Odour elimination in rooms, vehicles, and HVAC systems.
- Humidity and temperature control in greenhouses.
- Atmospheric fog and haze for events, stages, and photography.
Thermal vs Cold Fogger: Which Should You Choose?
Choose a thermal fogger when you need a dense, far-reaching fog outdoors, for example large-scale mosquito control. Choose a cold (ULV) fogger when you want flexible indoor and outdoor use, precise droplet control, and the ability to apply water-based disinfectants without heat. Many professionals own both because each suits different jobs.
How to Use a Fogger Safely
Foggers disperse chemicals into the air, so safety matters. Always read and follow the product label for the liquid you are using, wear appropriate protective equipment such as a mask, gloves, and eye protection, and ensure good ventilation. For indoor total-release foggers, keep people and pets out for the stated time, and never use more product than the label recommends. Keep foggers away from open flames when using flammable solutions.
How to Choose the Right Fogger
When comparing foggers, consider the job you need it for (pest control, disinfecting, or events), whether you will use it indoors or outdoors, the tank capacity for how long you can work between refills, the adjustable droplet or particle size, and whether a handheld, backpack, or trolley design suits your space. Matching the machine to the task is the single most important step.
Frequently Asked Questions
Is a fogger the same as a bug bomb?
A bug bomb is one type of fogger, specifically a total-release fogger that empties its full contents to treat a closed room. Not all foggers are bug bombs; many are refillable handheld or backpack machines.
Are foggers safe to use indoors?
Many cold and disinfectant foggers are designed for indoor use, but you must follow the product label, ventilate the area, and keep people and pets out during treatment when required.
What liquid do you put in a fogger?
It depends on the purpose: insecticide for pest control, disinfectant for sanitising, or a glycol or glycerin-based fluid for event fog machines. Always use a liquid the fogger is rated for.
What is the difference between a thermal and a cold fogger?
A thermal fogger uses heat to create a dense visible fog, while a cold (ULV) fogger uses air pressure without heat and offers more control for indoor use.
Conclusion
A fogger is a simple but powerful tool that transforms liquid into a fine, far-reaching fog. From controlling mosquitoes and disinfecting rooms to creating atmosphere at an event, the right fogger, used safely and matched to the task, makes big jobs faster and more effective.