what are the ways to kill mold?

We Rank and Compare the Best Ways to Kill Any and Every Type of Mold

Whether you do DIY or hire a professional you have only five options for killing mold: steriliants, disinfectants, ozone , UV Light, and environmental probiotics.

For sterilants and disinfectants you have two methods — fog or liquid.  To kill mold alone is not enough, which we discuss below.  The last step which we will very briefly go over the different options for removing or covering up the dead mould in order to eliminate the visual eyesore of visible dead mold and / or take out building materials that are need to be removed because they no longer serve their purpose well. 

Your Options for Killing Mold

Disinfectants & Sterilants


UV Light

Environmental Probiotics

Water sustains and cultivates mold. Unlike a plant, you can’t kill mold by not giving it water, but you can at least make it go dormant so that it stops growing and stops releasing spores with toxins into the air that then could create a whole host of health issues.Eliminating source(s) of excess moisture is the most important thing you can do, and must be done first!  However cutting off the water source won’t stop the mold from sporing immediately.This leads us to the next most important thing to do, which is to kill the mold(s).All four go-to solutions we discuss here are effective in this mission. Like every comparison in life though, each has its pros and cons, and each depends on other factors, like how the solution is applied, and the skill of the individual applying the solution. Our objective on this page is to compare the efficacy of different ways to kill mold, not to share what you need to do to kill it.  If you want to learn how to kill mold, and get a lot of your questions answered from a third-party resource, we recommend: https://www.epa.gov/mold.   There you will find lots of good advice if you plan to do it yourself, or need further information to help you evaluate who to hire.The short answer to the question of the most effective way to kill mold is:  a sterilant or disinfectant applied as a dry fog, followed-up with a preventive environmental probiotic automatically dispensed into your air 24/7 which will keep every-day mold at bay in your air and on surfaces throughout your property.  This answer is biased.  However, below we explain why any other solution doesn’t even come close to being as effective.


The EPA does not publish a list of broad-spectrum fungicides. So we have to rely on the individual fungicidal claims of household and commercial-grade  disinfectants, sterilants and sporicides, then look up those claims one by one through the EPA’s search tool — https://search.epa.gov/epasearch.  The reason for this may have something to do with there being over 100,000 types of fungi and molds.  It also may be because there are so many different chemicals with fungicidal properties. There are hundred of fungicidal chemicals -https://en.wikipedia.org/wiki/List_of_fungicides.

Given the complexity how could the most effective disinfectant ever be determined?! And is it realistic to expect a disinfectant to kill all molds? 

An absolute answer is tough, but the claim of killing all molds can be made with near 100% accuracy.

Practically speaking, you will only encounter a very small percentage of these molds in your home. Most molds simply won’t thrive in a home environment, like they do in nature and agriculture, and therefore you really only need to kill a small number of molds to get real results. Also, if a disinfectant can eliminate the most difficult type of mold to kill, it can be safely assumed it will get rid of the rest.  Most disinfectants fall into this category

A “sporicide” capable of killing c dif is considered to be effective against every other fungi, bacteria and virus on earth.  An epa registered K-list “sporicide” is the most powerful cleaner available. These are really only necessary for use in hospital environments. 

The next most powerful type of cleaner is a sterilant.  It does what it says it does; it sterilizes an environment.  It is only slightly less powerful than a sporicide, literally capable of killing everything but c dif spores.

The next most potent are antimicrobial disinfectants. There are hundreds of different EPA registered products to choose from, and all will have fairly similar efficacy in killing all types of mold.  Disinfectants are usually sufficient for the job, and represent sufficient level of potency.  But you will soon learn, that, potency is not necessarily the most important factor when it comes to efficacy

Let if suffice that if you were to do a search online almost any EPA registered antimicrobial disinfectant will show it has registered claims for one or more specific molds.

The Pros

  • All disinfectants and sterilants that we are aware of come in a liquid form. However it can be dispensed with a soaked rag, via a mist, or by using either a wet fog or dry fog. It can flex to resources and budget.
  • The biggest pro is that when fogged, it can reach wherever there is airflow, including behind walls, and into HVAC systems and insulation and rugs.
  • If atomized small enough, the droplet size can be smaller than most mold spores, allowing it to go wherever a spore goes
  • Dry fog with the right sterilant or disinfectant allows you to treat soft surfaces effectively. This is a bigger deal than it sounds. 
  • Can be the least expensive. 
  • Certain fungicidal disinfectants and sterilants can denature the mold DNA – crucial so that the dead mold doesn’t continue to cause allergic reactions
  • Certain fungicidal disinfectants and sterilants can cut through biofilms protecting mold
  • effectively kills viruses and bacterium as well

The Cons

  • Application with a wet rag using fungicides like bleach, can actually make mold spread.
  • Atomizing certain chemicals into a fog increases the liklihood of damaging your longs and you will want to have proper PPE
  • Certain fungicidal disinfectants and sterilants don’t denature the mold DNA
  • Certain fungicidal disinfectants and sterilants are ineffective at cutting through biofilms that protect mold

Use the wrong solution and use the wrong method to apply it, and/or don’t include demolition when absolutely necessary, and your experience could be similar to the following…

" February and March of 2008 we “killed” mold, sprayed with Lysol, bleached subfloor and ran fans, replaced carpet but left mold in the subfloor, walls, etc. Eight months later I was so sick I could not get out of bed."


Sterilants are a stronger form of disinfectant. See “Disinfectants” above. 

All cleaners that have cidal properties are usually referred to as disinfectants. 


Ozone is extremely straightforward. It comes in one gas form, that is dispensed by an ozone generator.  It takes the air your home and generates ozone gas to begin the process of sterilizing the air and everything else in your home. 

Ozone particles are extremely tiny. Smaller than any droplet can be made of any liquid sterilant or disinfectant solution.  It would seem like it would be the best solution out there.  Problem is, it has very strong negative side-effects. 

The Pros

  • Dispenses only as a gas — extremely unmessy process
  • It can reach virtually everywhere, including behind walls, and into HVAC systems and insulation and rugs.
  • Can treat soft surfaces effectively. 
  • You can purchase an ozone generator inexpensively on Amazon.
  • Mixed messaging, but it appears to denature mold – it seems to be produce of concentration
  • Can cut through biofilms protecting mold at high concentrations
  • Effectively kills viruses and bacterium
  • It helps get rid of chemical off-gassing and fragrances in a home

The Cons

  • Effective ozonating requires high doses, and at high doses – ozone can destroy belongings which forces you to throw away belongings
  • To avoid loss, move all belongings out of your space
  • Can’t return to an ozonated property for days, possibly longer
  • Can trigger or create smells that make you sick, and may not be solvable.

"The last time I used ozone something went terribly wrong, it felt increidbly toxic after and I had severe reactions, and I was never able to return to that rental house. My belongings were ruined as well."

UV Light

UV light wins as the best disinfection solution in many applications, it is clean, healthy, non-toxic; although you don’t want to be in the room for an extended period when running. 

The Pros

  • An un-messy solution
  • Extremely good when engineered for dedicated tasks
  • Can denature at the correct wavelengths and strengths 
  • poor penetration into the matrix of biofilms
  • Effectively kills viruses and bacterium
  • kills fairly quickly
  • Hands off, so it is not labor intensive
  • Immediate re-entry into the room
  • Relatively safe, meaning the precautions are intuitive
  • Can slightly bleach certain surfaces – but likely to have no effect in a one time mold remediation project

The Cons

  • Effective destruction of some viruses and most mold and bacterial spores usually requires much higher UV exposure than is provided in a typical home unit.
  • For the effective use of UV light – DIY is not a realistic option
  • The biggest issue is it will miss a lot of the mold you are trying to kill

UV light is good, but it only kills what is shines on in sufficient doses. If there is a complimentary to use it, we are not aware, but UV light alone for mold remediation feels like a guaranteed least effective solution.

Mold has lived, survived and thrived on earth for millions of years in spite of 12+ hours of UV radiation.  The example research is a very typical and predictable outcome…

"UV-C administered as a 1-minute cycle in a UV-C box or a 30-minute cycle by a room decontamination device reduced contamination but did not meet criteria for decontamination of the viruses from all sites on the N95s. The high-level disinfection cabinet was effective for decontamination of the N95s and achieved disinfection with an extended 31-minute cycle."

Methods of Application




UV light


wet fog

dry fog

The method of application matters as much as the solution used to kill mold.  In some cases like ozone and UV light the application medium is already “baked-in.”  But the concentration is not.  Regardless of the application method the three most important things are: surface area treated, the concentration of the solution, and the proper sufficient dwell time.  Get those three right, and it will be worthwhile, but perhaps not worth the cost for the given quality of the end result.

Surface Area Treated

Nothing may be more important than ensuring that all surface areas that need to be treated are treated.  How good is a maid surface that you pay to clean your whole home, but leaves once they have cleaned 15% or even 60% of it? 

Ozone wins on this metric, it is the smallest molecule capable of penetrating every gap that air is able to penetrate..  Of course UV photons are smaller, but they just can’t reach everything in a safe, consistent and economical way.  It is effective but way too damaging at the required concentration levels to be a practical way to kill mold. 

This means the clear winner highly atomized dry fog, like the patented dry fog atomization process used by Mold Busters Greenville.  With our fog, we easily treat 10X to 1000X more surface area than any other mold remediation method.  Because it goes on dry, leaves no residue, is safe and dissipates into natural , environmentally friendly components, we can literally fog every single visible surface at your property, as well as most of the invisible and hidden surfaces.   No method at our level of safety comes anywhere close to treating the surface area we treat. This is why it is so easy to guarantee results for our customers.  

If you don’t get mold that has taken root, and is dormant, the next 24 hour period that you have 60% humidity or greater in that space, the mold can become capable of sporing again. 

We are less costly than other options, and we know we are far more effective, so there is no reason to consider any of the other options.


We all  understand that if water something down too much it can make it ineffective.  If I attempted to clean with vinegar or hydrogen peroxide for example, and poured a little in a big bucket of water, I would never create a solution lethal enough to mold to have any effect. 

This is a crucial aspect, but it is typically easy to get right, if you just follow the instructions from the solution provider.  Whether that solution is  disinfectant, UV light, ozone or any other solution.

Dwell Time

Dwell Time is the amount of time that a chemical is actively working to kill what it is being targeted. 

Like concentration, this feels like common sense, but most people are completely unaware of how important it is.

Remember there are hundreds of different disinfectants and sterilants you could use, but some may require that the solution remain wet and in contact with the mold for 3 minutes or 5 mintues or 10 or maybe even 20 minutes in order to be sure that you killed it.  If you get the concentration right and even coat all surface areas, but don’t get the dwell time right — you may not kill but a very small percentage of the mold. And end up spending a lot of money for nothing. 

With dry fogging, if there is a fog touching a surface, then the disinfectant is at work. When we fog we maintain a foggy enviroment that far exceeds the required dwell time for the hospital grade sterilant and antimicrobial disinfectants that we  use. 

Want the most effective solution, by a landslide, for killing mold?


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