How to Use an Ozone Generator to Kill Mold


This post may contain affiliate links. When you buy through some links on this post, we may earn an affiliate commission.

When your home has been damaged by water, you may find the unpleasantness of mold. There are a few ways to eliminate it, but does an ozone generator kill mold? While ozone generators may be an air purifier, they can also kill mold spores. Even professionals use ozone generators to kill mold.

Some people might tell you the dangers of using an ozone generator, but they are one of the most effective air purifiers if you use it safely. For these reasons, we've created guidelines for safe O3 machine operation.

The dangers of using an ozone generator come from the ozone itself. Ozone is composed of oxygen molecules that have three oxygen atoms in them. This is more than the normal oxygen molecule, which has two.

Because ozone gas is composed of these three-atom oxygen molecules, it is very reactive to organic things. “Organic” is just another way of saying “living”.

This means that it can negatively affect humans, pets, and plants. However, this also implies mold, bacteria, and viruses are affected. There are many dangers of using ozone, but there are ways to use it safely.

Because ozone is so reactive to organic things, it can cause damage to their respiratory system, make their cells act differently, and more. It’s unsafe to breathe in, but ozone generators are one of the best things to obliterate living spores.

Note: Ozone generators can kill mold spores, but it will not remove the dead mold. It also does not correct the conditions that allowed the mold to grow in the first place.

What is mold?

Mold is a multicellular organism that grows in warm, damp areas. The type that grows in your house can be toxic to you and others around you, so it should be removed.

House molds can also weaken the home's foundation, allowing rot and insects to come in and cause pricey repairs. However, it can also cause a lot of problems for people. It can leave you with discomfort in your chest and head, make it difficult to breathe, and even cause fatigue.

People who are sensitive to mold can end up with sickness or worse. It’s extremely difficult to eliminate, so a professional may need to be contacted first.

How Do Ozone Generators Kill Mold?

As stated above, ozone generators produce ozone and ozone affects organic things. Mold is organic, considering it is a fungus. While ozone won’t completely kill all the mold in your home, it will do well to get all the spores and keep it from spreading.

If you’re not sure how to remove mold completely, you should start on finding where the water is coming from. This can range from a leaky pipe to humidity, so learn how to repair water damage first.

Since ozone is composed of three oxygen molecules, it can combine itself with things like mold and mold spores. It will change them in such ways that it kills the spores and cells that compose the mold. This is the same way it removes odors and other things: killing the bacteria that cause it.

Because of its highly reactive state, the mold and mold spores will die from the gas messing with its chemical makeup.

Keep in mind that ozone generators do not kill mold completely by themselves. They must be used in conjunction with other mold remedial processes like replacing surfaces, antimicrobial substances, and water damage restoration. It will certainly help the mold and mildew smell that will come with it and stop the spreading of the mold, though.

How To Use Ozone To Kill Mold


Prepping The Space

mold on drywall

Before getting started, it's important to remember that ozone will not penetrate through walls, floors, etc. It can only affect what it can get to, which means that it can't kill mold spores that are growing deep inside building materials like drywall, wood, etc.

These types of porous materials must be removed to get rid of the mold that is growing on them. Ozone may remove the smell, but it doesn't physically remove mold or mold spores. Physical removal requires mold remediation services.

To begin preparing the room, you should clean the room as thoroughly as possible first. A bathroom, for example, will need all hard surfaces in the room cleaned with a strong surface cleaner such as bleach.


Dehumidify The Space

For the ozone to work effectively, you need to dehumidify the space. Ozone works best in a dry environment.


Vacate The Space

Remove people, pets, and plants from the space while treatment continues. This includes fish in aquariums.  Ozone is a gas that can cause severe respiratory distress and even death if you're exposed to it for too long. Do not risk this.


Set The Timer For 3-30 Hours

Set up the ozone generator in the middle of the space to be treated. Leave a window cracked slightly to allow new oxygen in; if you leave the space completely sealed up, the machine will run out of oxygen to convert into ozone, which won't be as effective.

Depending on the space size you're dealing with, you want to run the machine anywhere from 30 minutes to a couple of hours.

If your ozone generator doesn't have a timer on it, you should purchase a smart plug like this one on Amazon that you can use to shut the machine off without going into the room. You don't want to rely on going into the room to shut it off.


Turn The Machine off And Wait

Your machine should turn off by itself if it's on a timer. If it isn't, turn it off using the app for the smart plug recommended previously. We don't recommend holding your breath and entering the room to do this. You should also open the space up to allow the ozone to dissipate. Stay away from the entryway.

After the machine is off and the space is opened up, you must wait at least a few hours to let the ozone fade before re-entering.


While ozone can harm humans and other living things, it kills mold and bacteria. With the mold spores killed from the air, it will eliminate the moldy smell that comes with it. Ozone generators are not a magical box that will make all your problems disappear, though.

There are many applications for ozone, and it can be a great tool if used properly and safely. If you choose the ozone route, look at our buyer's guide. We understand how they work, why they work, how to use them, and a strong understanding of output and quality from real-world experience in the field.

Many use an ozone generator in conjunction with your local emergency restoration services, such as water damage and mold remediation, like our company provides to make sure mold never comes back or starts after having water damage in the home.

If you’re ever unsure and don’t want to risk anything, many professionals are out there. They can help you with your mold problem. Ozone is dangerous. That much can be said. However, it is one of the best air purifiers, considering it kills the mold spores and bacteria that will cause odors. These are unpleasant smells, so consider using an ozone generator to eliminate them.

Recent Posts