Because most mold spores are microscopic, when you find those fuzzy splotches on the wall, you see only a fraction of the mold that’s actually there.

That means cleaning the visible mold won’t always get rid of all the mold. Mold foggers are designed to help with this problem by applying a mold-killing mist to a broad area. While these devices offer some benefits, they’re only a small and optional part of an effective mold remediation plan.

How Mold Fogging Works

A mold fogger produces a mist of antimicrobial and odor-controlling solution designed for mold remediation. This mist evenly coats everything in the area and either kills or encapsulates mold on all types of surfaces. Available in handheld and stationary forms, mold foggers can be used to treat entire rooms, small spaces such as cupboards and cabinets or individual pieces of furniture. They also work outside the house, such as in the garage, car, or storage shed.

Fogging is an effective treatment offered by mold remediation specialists and often manageable with a do-it-yourself kit, but its effects are limited. Most mold fogging solutions kill mold spores, stopping them from spreading and reducing or eliminating musty odors. They cannot, however, clear away actively growing mold or prevent more mold from showing up when the cause of the problem hasn’t been solved. Even dead mold spores are allergens and potentially toxic, so fogging alone isn’t enough. It’s primarily useful as an extra precaution and it’s never necessary.

© burdun –

Consider fogging only after you or a qualified professional have taken all the essential mold remediation steps. Start by correcting the conditions that allowed the mold to grow, such as high humidity or poor ventilation. Then dry out wet areas and remove porous material that can’t be cleaned. That might mean removing drywall, insulation, carpet, and carpet padding. Fogging can treat these materials if they might have picked up some mold spores, but it can’t save them once they have visible mold growth. Finish by cleaning up with a HEPA-filter vacuum and a HEPA-filter air cleaner.

Today’s Homeowner Tips

Fogging is especially useful in cases where replacing affected material isn’t possible or practical. If you find a patch of mold somewhere in your heating and cooling ductwork, fogging after clean-up is more affordable than replacing all the ductwork.

Choosing the Right Fogger

If you decide to fog an area yourself, you’ll need to choose fogging equipment and a mold fog solution to use in the equipment. Look for a true fogger that produces particles of 50 microns and finer, not a mister that produces only larger particles.

While handheld foggers are convenient for small areas such as cupboards, a stationary or static model might be more comfortable for large areas. A heavy-duty fogger can treat as much as 400 sq. ft. in one go. If you need to treat hard-to-reach areas such as the attic or crawlspace, look for a high-powered fogger that can spray the distance you need.

When you choose a mold fogging solution, read the directions carefully. Some products commonly used for mold fogging aren’t actually approved for that purpose. An antimicrobial product that might be perfectly safe applied as a liquid can be harmful when turned into a fine mist and inhaled. Hydrogen peroxide fog, for example, can damage household items and, more importantly, your lungs. This also applies to products registered with the EPA under the Pesticide Act.

When you’ve found a safe product, look over the producer’s claims. Some only encapsulate mold, meaning they cover it and stop its spread, but don’t immediately kill it. Others claim to kill the mold and even remove mycotoxins.

Check that the product works on the surface you want to treat, such as wood, drywall, concrete, or fabric. If you have pets or children, make sure the product is safe for use around them and their bedding and toys. A product that dries fast is also a plus.

Today’s Homeowner Tips

Be wary of water-based botanical products. Mold spores are hydrophobic and repel water, so fungicides in a water-based product might not reach the mold spores. What’s more, fogging water can add to your moisture problem.

Using Your Mold Fogger for Optimal Effectiveness

How you use your mold fogger affects how well it can do its job. Correct use varies by equipment, so always follow the manufacturer’s directions. The basics are simple:

  • Prepare the area by removing or covering electronics and items that might be damaged by moisture, such as paper and delicate textiles.
  • Add the mold fogging liquid to the fogger tank and adjust the settings. The finer the mist, the less risk of damage.  
  • If you’re using a handheld fogger, hold it 18 to 24 inches away from the surfaces you want to treat. For a stationary fogger, place it a minimum of 18 inches away from any surface.  
  • Let the fogger run for around 10 minutes. For a stationary fogger, turn the equipment by a one-quarter turn every two or three minutes to prevent run-off.
  • Turn the fogger off, leave the room, and let the fog dissipate for around half an hour.
  • Dry the area by opening windows or turning on fans. Leave again until the area is thoroughly dry.

Mold foggers do work, but their role in mold remediation is a minor one. If your goal is to stop any lingering mold spores from taking hold and get rid of musty odors, fogging is worth the effort. Even so, it should be the last step in your mold removal process.

Editorial Contributors
avatar for Henry Parker

Henry Parker

Henry Parker is a home improvement enthusiast who loves to share his passion and expertise with others. He writes on a variety of topics, such as painting, flooring, windows, and lawn care, to help homeowners make informed decisions and achieve their desired results. Henry strives to write high quality guides and reviews that are easy to understand and practical to follow. Whether you are looking for the best electric riding lawn mower, the easiest way to remove paint from flooring, or the signs of a bad tile job, Henry has you covered with his insightful and honest articles. Henry lives in Florida with his wife and two kids, and enjoys spending his free time on DIY projects around the house. You can find some of his work on Today’s Homeowner, where he is a regular contributor.

Learn More