The truth about ozone and how it can be used safely to disinfect your mini-split air conditioners

The truth about ozone and how it can be used safely to disinfect your mini-split air conditioners

Our air conditioners and mini-split systems are important appliances to have in our home. It's a necessity that helps us stay cool during the hot summer and warm in the winter months. But did you know that your mini-split AC can also be one of the dirtiest appliances in your home?  Most people don't realize this, but mold and bacteria grow on the coils inside the unit and could lead to respiratory disorders or possibly worse if not cleaned properly. In fact, according to research from Yale University, indoor levels of certain pollutants are often higher than outdoor levels because many homes have poor ventilation systems, very little window area for fresh air exchange and the recirculation of air through our heating and cooling devices. So how do we safely disinfect our AC system without harming ourselves? The answer is ozone! Ozone is a disinfectant that kills airborne bacteria, viruses and mold spores. It's safe to use indoors when applied correctly. In this blog post, we'll show you why ozone is so effective and how it can be used safely to disinfect your mini-split AC.


What is ozone?

Ozone is a gas with three atoms, each of which has one oxygen atom. As per the EPA’s website “Stratospheric ozone is formed naturally through the interaction of solar ultraviolet (UV) radiation with molecular oxygen (O2). The "ozone layer," approximately 6 through 30 miles above the Earth's surface, reduces the amount of harmful UV radiation reaching the Earth's surface.”

Oxygen and Ozone Molecule

Molecular oxygen (O2) is the normal oxygen we breathe and is present throughout the atmosphere. It can be split apart by the sun's rays into two single oxygen atoms and one of these can then recombine with an O2 molecule to form O3, ozone. The gas has a distinctive scent reminiscent of chlorine, and can sometimes be smelled after a thunderstorm, when lightning zaps oxygen molecules apart.

Ozone can also be created artificially by means of extremely high voltages or by means of UV-light. Both methods involve the decomposition of the oxygen molecule. This causes oxygen radical formation. These oxygen radicals can bind to oxygen molecules, forming ozone (O3).

Ozone as a disinfectant

Ozone has a greater disinfection effectiveness against bacteria and viruses compared to chlorination. Unlike chlorine, ozone leaves no harmful by-products in the water or the environment. Ozone quickly reverts back to pure oxygen if unused. Ozone has many other uses as well: It purifies water systems and may be used to protect food from spoilage or decay, while at the same time preserving its flavor. It is used regularly in hospitals and on medical devices for high disinfection. And, onsite generated ozone has been found to be effective at killing household germs by creating an environment that prohibits their growth.


What is ground-level ozone?

As brought out by the EPA, Tropospheric, or ground level ozone, is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). This happens when pollutants emitted by cars (the biggest culprit), power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight. So in a nutshell, ground-level ozone is air pollution, which at unhealthy levels does impact humans, animals, and vegetation.

Ground Level Smog


Why use ozone for a mini-split air conditioner?

Mold is a common problem in air conditioners, and the issue can be exacerbated by high humidity. Mold thrives on organic matter that has been exposed to water for long periods of time. The heat from your AC then causes the mold to grow faster than it otherwise would due to higher temperatures. With the air from the mini-split AC constantly circulating through the unit into your home, mold spores are sometimes picked up and pushed into your living areas. It’s important to remove the mold spores so as not to inhale them causing respiratory disorders or more. You can clean the visible mold but the issue is what do you do about the areas you can’t see inside? This is why ozone is so valuable and effective in this kind of disinfection. As mentioned earlier, ozone is a gas, and gas has the ability to penetrate into areas that we, or anyone else, never could reach. Unlike another option, UV light, which only can disinfect what it sees, ozone floods the internal components, specifically high mold and bacterial buildup areas such as inside the coils and blower wheel. Any mold, mildew, bacteria and other contaminants that are touched by ozone; are instantly killed and deactivated.

Mold in Air Conditioner Mini Split

Another benefit of regularly using ozone for mini-split disinfection is that ozone has the ability to inhibit and slow the growth of mold. Mini-split ACs inner components are naturally dark and damp environments which lead to continual mold growth, but using ozone regularly means even the organic buildup of mold can be controlled in between scheduled maintenance.

A pain point of many mini-split air conditioner owners is that they find that their system starts to give off an extremely unpleasant smell. (hint hint … what you are most likely smelling is old mold inside the unit). Sometimes referred to as a ‘dirty sock syndrome’, musty, mildewy, sour or even a vinegar like smell.  All of this can be rectified with the use of ozone. Not only does the ozone disinfect, but ozone can eliminate the smell of VOCs.


How PureAC uses ozone safely inside the home

We discussed what ozone is, how it’s an effective disinfectant and even talked about cautions with ground-level ozone. After reading all this information maybe you would like to use ozone to disinfect your mini-split AC but are still worried about making sure it is safe for you and your family inside the home. PureAC has done this for you. Let’s explain how PureAC works and why you can feel confident about it’s safety.

PureAC Secure Specialized Cover

Cover: The PureAC device was engineered with a specialized cover that is ozone resistant, which means when placed over your unit the cover seals tightly around the edges. This advanced fabric encloses the disinfecting ozone within your wall handler, not allowing it to radically be released into your home environment. In addition, the specialized fabric will not degrade over continuous ozone cycles and aids in the process of making sure the ozone inside stays at an effective disinfectant level. You can also be assured that PureAC makes sure that its device stays within all acceptable EPA guidelines for ambient air exposure. 

PureAC Converting Filter

Filter: Built into the PureAC cover is a secondary safety which is an ozone filter. Ozone when passed through activated carbon immediately converts back to O2, breathable oxygen, and all oxidizing properties are removed. 

PureAC Disinfecting Device

Device: Once properly installed over your mini-split AC, PureAC generates ozone onsite. The complete disinfection process is 30 minutes. This includes 12 minutes of generated ozone and then an 18 minutes processing and rest time. Ozone has what's called a half life which means that it naturally will break down back to oxygen on it’s own. The processing time is not only important for disinfection but this also makes sure that when you remove PureAC from your unit that there is zero residual ozone remaining.

Another safety feature of the device is there are multiple safety switches. If while the PureAC is in a disinfection cycle and the unit is accidentally moved, immediately the safety switches will disengage and the unit will stop producing ozone.

Although many people are unfamiliar with ozone, it's a great disinfectant that when used properly is safe for the environment and our health. PureAC is a device that attaches to your mini-split air conditioner for use as an ozone disinfectant. Ozone kills microorganisms such as mold, mildew, bacteria and more importantly onsite. Here at PureAC we love using it on our own mini-splits because we want to make sure that the circulating air that is coming out is clean, pure air. If you would like more information about how this process works or are interested in purchasing, please contact us at

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