Which is Better: Thermal Fogger vs. ULV Fogger Sprayer

A fogger sprayer is a device or a machine filled with a liquid solution. When the machine is turned on, the backpack sprayer will turn the liquid solution into fine mists or fog. Depending on what type of liquid solution is added, it can disinfect the surfaces, and kill flying pests like mosquitoes.

There are two main types of fogger sprayers, namely thermal fogger and ULV fogger sprayer. We delve deeper into these two types and figure out the differences between the two and which one is the best fogger sprayer for you. Let’s begin!

What is a fogger sprayer machine used for?

A fogger sprayer machine is a versatile piece of equipment that turns the liquid solution into fine mists or fog. They are often used in pest control to kill flying pests and prevent them from coming back. The particles produced by mosquito foggers can stay in the air for a long time making them very effective in pest control. 

Man using a fogger sprayer machine to kill mosquitoes. Invatech Italia

For this application, the mosquito fogger machine is usually filled with insecticides or pesticides to get rid of flying insects. 

A fogger sprayer can also be used for sanitation. The disinfectant fogger machine became very popular because of the COVID-19 surge.

The disinfectant fogger machine is filled with disinfectant solution and used to disinfect all the surfaces in the treatment area. Using a disinfectant fogger with an effective disinfectant solution is highly effective in sanitizing and disinfecting hospitals, medical environments, spacious rooms, parks, food preparation areas, and more.

An outdoor fogger machine can be used in odor control, agriculture, and protecting your crops, animals, and stock. 

There are many applications of a fogger sprayer. It will depend on what liquid solution you added to its tank.

What is a thermal fogger sprayer?

A thermal fogger sprayer is a type of fogging machine which uses heat to turn the liquid solution into fine mists or fog. Typically, the particles produced by a thermal fogger sprayer are about 0.05 - 10 microns. It comes with a heat barrel, preheated to reach a high temperature using electricity, gas, or propane, depending on your fogger sprayer.

When a liquid solution is added to the thermal fogger machines, it will move to the heat barrel which instantly vaporizes the liquid solution. Because of vaporization, the particles produced by your thermal fogger sprayer are extremely small leading to dense fog, resembling smoke.

Because of the extremely fine and small particles produced by thermal fogger sprayers, the solution stays in the air longer making them ideal for pest control. Thermal foggers are the best mosquito fogger and are often designed with a backpack sprayer for ease of use.

What is a ULV fogger sprayer?

A ULV fogger sprayer is also called a cold fogger sprayer because of the cold fog and mists it produces. In general, the particles your cold fogger sprayer produces are in the 5 to 20 micron range which is bigger compared to thermal fogger sprayers. It uses air pressure to turn the liquid solution into fog and mists. They are powered using gasoline, compressed air, or electricity.

Professional using a ULV fogger sprayer to disinfect washroom. Invatech Italia

When a liquid solution is added to the ULV fogger sprayer’s solution tank, the tank pumps it using the motor. At the tank’s nozzle, pressure is applied to the liquid solution and turns it into fog and mists. 

Many ULV fogger sprayer lets you control the size of the particles they produce. Also, because heat is not used in the process of turning the liquid solution into mists or fog, they are ideal and safe for indoor use.

Difference between thermal fogger and ULV fogger sprayer

A fogger sprayer has two main types, thermal and ULV fogger sprayer. The objective and purpose of both fogger machines are the same. But in reality, they use different operations and require different liquid solutions. In addition, each type of fogger sprayer can be better used for a specific application compared to the other.

Let’s take a closer look at the differences between a thermal fogger sprayer and a ULV fogger sprayer. 


As the name suggests, the thermal fogger sprayers use heat to turn the liquid solution into mists and fog. It comes with a heating coil or barrel which is preheated to a high temperature. When your fogger sprayer is turned on, the heating coil will start to heat up inside the motor. And when the liquid solution gets in contact with the heated barrel, the solution will start to vaporize. Because of the vaporization, the fog and mist it produces are denser and finer compared to the ones produced by a cold fogger sprayer.

On the other hand, ULV fogger sprayers apply air pressure to turn the liquid solution into mists and fog. It is also called a cold fogger sprayer because it operates using cold fogging methods. To turn the liquid solution into mists and fog, the ULV fogger sprayer comes with a low-pressure, high-power air stream. When your cold fogger machine is turned on, the liquid solution is pumped into the special nozzle which is designed to make the air inside begin to flow in a swirling motion. The high pressure produced from this pushes the liquid solution through the nozzle into fine particles.

Particle Size

The particle size produced by your fogger sprayer will depend on the model of your fogging machine. However, a thermal fogger sprayer produces smaller particles, averaging from 0.5-10 micron range. On the other hand, a ULV fogger sprayer produces a bit bigger particles, averaging from the 5 to 30-micron range.

Professional in a protective suit using a fogger sprayer in room. Invatech Italia

Because of the smaller particles a thermal fogger sprayer produces, they are effective both indoors and outdoors. In addition, the mist and fog produced stay in the air longer making them perfect for pest management. The fog produced is very thick and visible to the eyes making it easy to see and control its direction. 

On the other hand, a ULV fogger sprayer produced bigger particles compared to a thermal fogger. Because of this, cold fogging machines are perfect for disinfecting and sanitation.

Uses of thermal fogger and ULV fogger sprayer

Both thermal and ULV fogger sprayers are used in similar ways. They can also use either or both water and/or oil-based liquid solution depending on the model of your fogger sprayer. However, there are cases when a thermal is more effective compared to ULV and vice versa. 

Thermal fogging machines produce finer particles and visible fog making them ideal for the following uses:

Insect control

For insect control, a thermal fogger sprayer is beneficial because the fog and mist are smaller. Meaning, that the insecticide and pesticide you use will stay in the air longer and will penetrate through dense vegetation better.

Direct outdoor application

Because the fog produced by your thermal fogger sprayer is more visible, it will be easier for the operator to control the direction of the fog and monitor the operation better. Also, heat is used in turning the liquid solution into fog or mist making them more ideal for outdoor use.

The smoke from mosquito fogger sprayer contrasts with the sunlight. Invatech Italia

Small, hidden areas

The smaller-sized particles produced by the thermal fogger sprayer can penetrate through smaller cracks and crevices in the floors, ceilings, walls, and other small and/or narrow areas.

A ULV fogger sprayer doesn’t heat up, reducing the risks of fire. In addition, the fog and mist it produces are not visible to the naked eye making them ideal for residential areas. Also, they are quieter compared to thermal foggers. Because of all these, ULV foggers can be used in the following:


As mentioned above, a cold fogger sprayer doesn’t produce too much heat making them ideal for indoor use.

Sanitizing, disinfecting, and odor control

The particles produced by your ULV fogger sprayer are larger and don’t stay in the air that long. These particles will drop to the surfaces in the treated area, sanitizing and disinfecting all the surfaces. Just add the right disinfectant solution to your cold fogger.

Mold and fungal control

Your cold fogger sprayer can be filled with fungicides and a mold control liquid solution.

Which fogger sprayer is better?

Both thermal and cold fogger sprayers have their own use, pros, and cons. Here are some advantages and disadvantages of both to help you choose which one is better depending on how you are going to use them.

Infographic Thermal vs.  ULV mosquito fogger sprayer. Invatech Italia

Choosing which type of fogger sprayer is better will mostly depend on what your goal is. If you are planning to use your fogging machine to get rid of mosquitoes and other insects, go for thermal. But if you want to start your own sanitizing and disinfecting business, choose ULV fogger sprayers.

Whichever type of fogging machine you choose, you will not go wrong with Invatech Italia. Contact us to find out more about fogger sprayers.