Updated May 2022
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BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We only make money if you purchase a product through our links, and all opinions about the products are our own. Read more  
BestReviews spends thousands of hours researching, analyzing, and testing products to recommend the best picks for most consumers. We buy all products with our own funds, and we never accept free products from manufacturers.Read more 
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Buying guide for Best mold killers

What can you do when mold makes an unwelcome appearance in or around your home? You could break out the soap and water, get a scrub brush, and start applying a lot of elbow grease, or you could take care of it the easy way: with a mold killer.

Mold can cause a lot of health-related problems, so you need to address it as soon as it appears. There are lots of choices available. Some mold killers are best used on concrete but not wood while others are designed specifically for use on wood. Mold killer can take several forms, too. There are sprays, foams, gels, and concentrates that need to be diluted before you use them.

It’s crucial that you pay close attention to safety issues with mold killers due to the chemicals they contain.

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Many mold removers are based on bleach or bleach derivatives, which is why there is a strong odor associated with them.

Key considerations

Mold is classified as part of the fungi kingdom. It doesn’t use photosynthesis from the sun to get its energy. In fact, UV rays from the sun inhibit mold growth. Mold derives energy from the material it is growing on, “eating” it as it grows.

Periodically, mold releases spores into the air, like tiny floating seeds. Once those spores land on a suitable material under the right conditions, they will begin a new colony of mold. Let’s take a deeper look at what causes mold.

Expert TIp
Always store mold killers out of the reach of children and pets.
BestReviews Cleaning Expert

What causes mold?

Mold needs a food source such as cotton, drywall, or wood. It only grows in the dark, so to thrive, it needs an area that is sheltered from the sun. It also needs warmth and moisture. Mold can’t grow in freezing temperatures or dry climates.

A shaded backyard near a swimming pool is an excellent place for mold to grow.

What health problems can mold cause?

Mold spores that are released into the air can cause health problems such as allergies and lung infections. It can even cause hair loss. In extreme cases, mold can cause death.

How can I remove mold?

Given the danger posed by mold, you need to get it out of your house. Because molds “eat” the surface they’re growing on, they need to be removed before the surface is weakened or destroyed.

Step one: The first step is to spray the affected area lightly with water. This helps prevent the escape of spores into the air.

Step two: Next, scrub the area lightly with a scrub brush. This will knock off the outer layer of mold and break up the inner layers, exposing them for the next step.

Step three: Spray the area with mold killer. Be careful to follow the directions on the bottle concerning ventilation, PPE (personal protective equipment), treatment surface, and other cautions. Many mold removal products will cause damage if you use them on the wrong surface. Luckily, there are mold killers for almost any surface.

Step four: Once the mold killer has finished its chemical work, thoroughly rinse the area to remove any remaining chemicals.

PPE

The EPA recommends the use of PPE when cleaning mold, regardless of any recommendations from the product manufacturer. At a minimum, the EPA says you should always wear a respirator, goggles, and rubber gloves. This is to protect you from mold spores, not the cleaning product. However, you may need to wear PPE to protect yourself from the chemicals in the mold remover, too.

Features

Inside/outside

Mold treatment inside the house poses special problems due to the strength of many mold removers. The chemicals in mold killers are often hazardous, acidic, even toxic. They can burn your skin, and the fumes can irritate your eyes, nose, mouth, and lungs.

Before using a mold remover, vent the room to the outside by opening as many windows and doors as possible. Use two or three fans to pull air from the rest of the house and blow it through the affected room out of the house. Make sure all of this is done before you begin applying the mold killer.

Note: Gels might seem like they would be safer than sprays, and some are, but some of them have been reported to create the same toxic fumes as sprays. Read the label thoroughly before use.

Expert Tip
Before each use, always read the back of the bottle. Mold killer cannot be applied to certain materials, and you don't want to ruin the thing you're trying to clean.
BestReviews Cleaning Expert

Chemicals

Dodecyl dimethyl benzyl ammonium chloride, an ingredient in some mold removers, is a surfactant (surface active agent), meaning it sticks to things. If a mold killer contains it and you get some on you, it won’t come off easily. Whatever it is mixed with will stick to you, as well.

Bleach and ammonia are common chemicals in mold removers, and both produce strong toxic fumes. Other active ingredients often used are sodium percarbonate and N,N’ethylenebis (N-alkylamide).

Sodium hypochlorite salt (hypochlorous acid and sodium) is another ingredient found in many mold killers. The MSDS (material safety data sheet) on this substance is seven pages long and contains many cautions and warnings.

In short, mold killers are excellent products, but they are composed almost entirely of hazardous chemicals. You must be cautious when using them.

Untreatable surfaces

Due to the chemical ingredients in mold removers, many of them should not be used on colored fabrics, aluminum, steel, copper, and metal ductwork. The chemicals can permanently stain or discolor these surfaces and materials. If you have mold growing on your wooden deck, remember that there are mold killers that can be safely used on wood, but there are others that cannot be used on wood. Carefully read the label and/or description for each product.

Concentrate form

Some mold killers are sold as concentrates that must be diluted with water before use. Be sure you know which is which. If you use a concentrated mold remover without diluting it, you could cause permanent damage to the surface you’re treating.

"Mold removers will not work on paintings. Prevention is your only option."
STAFF
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Accessories

Scrub brushAlthough many mold removers claim to be “scrub-free,” it’s better to have a scrub brush just in case there is some stubborn mold that doesn’t want to come off.

Cleaning gloves: To protect your hands from any harsh chemicals in the mold killer you use, you'll want to use a pair of cleaning gloves. Make sure your gloves are in good condition with no cuts or tears.

Respirator: Avoid inhaling mold spores by using a respirator. 

Expert TIp
Wear gloves and protective eyewear every time you use mold removers.
BestReviews Cleaning Expert

Mold killer prices

Inexpensive

The low price range is under $10 per 32-ounce bottle. These mold removers are usually not as effective as pricier products. Other than gloves, PPE isn’t usually required.

Mid-range

The medium price range is between $10 and $25 per 32-ounce bottle. These are strong chemicals that work, but they definitely require the use of PPE.

Expensive

The high price range for mold removers is anything over $25 per 32-ounce bottle. These are usually professional-grade cleaners. Some may require the use of a full face mask.

Tips

  • Always stand “upwind” of the area you’re spraying so none of the mist drifts back onto you.
  • If you stand too close to the surface you’re spraying, some of the mold remover could splash back on you. Hold the remover at arm’s length and keep the nozzle 12 to 24 inches away from the surface.
  • Store the mold remover in a cool, dry place away from any flames or sources of ignition.
  • If areas of your home and yard provide the right conditions for mold, check those areas several times a year, such as during your spring cleaning and when you winterize your home. Mold spreads, and if allowed to grow can be expensive and difficult to remove.
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As a general rule, you can gauge the strength of the fumes by the speed with which the mold remover works. The faster it is supposed to work, the stronger the smell is likely to be.

FAQ

Q. Can any mold remover be used on clothes?

A. No. Detergent and hot water are the best way to remove mold from clothes.

Q. Are gel mold removers better than sprays?

A. There is less chance of misapplication with a gel, but it is the active ingredients that determine the effectiveness, not the method of application.

Q. Can I reapply mold killer as prevention?

A. It depends on the product. Many products can be safely reapplied once a month after the initial cleaning. As always, though, you should read the directions for your particular product (and your particular surface) before taking action.

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