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Common Types of Household Mold

Most of us know about mold. We know it’s bad for our homes and can be costly and difficult to remove. We also know that mold comes with potential health risks and can affect people of all ages.

Understanding what mold is, how mold grows, how to keep it away, and what to do when it appears can be important for your overall health.

Let’s take a closer look at mold and see what you can do to keep you home clean. 

What is Mold?

Mold is a type of fungus, a biological family that includes yeast and mushrooms. Mold grows in multicellular structures called “hyphae” which grow in a thread-like shape.

Although the individual structures are too small to be seen with the naked eye, mold growth usually appears as black, blue, or green. The color of the mold is often influenced by the nutrient source; in other words, what the mold is eating.

Mold Growth in Your Home

Like all lifeforms, mold requires water and food to stay alive and grow. It also needs oxygen and temperatures ranging roughly 40 to 100 degrees Fahrenheit.

Indoor mold gets its food from decomposing organic substances, and it can find these substances from most paper and wood products.

This is why gypsum wall board and other wood materials are particularly susceptible to mold.

Mold can also digest synthetic materials, including adhesives, paint, and pastes. While it can’t get nutrients from metal, glass, plastic, or concrete, it can feed off of dust and dirt layering these materials.

Mold is very resourceful and only needs a small amount of water to survive. Even though mold fungi often grow from water damage, mold can typically get enough water from the air itself, provided conditions are humid. In many cases, mold will grow when the relative humidity is 60% or more.

Therefore, places like Florida are havens for mold and mildew growth.

By feeding itself on these nutrient sources, as well as the available water and moisture, mold grows by extending the hyphae as if they were microscopic hairs.

To reproduce, mold releases spores, which are essentially tiny seeds. These spores are particularly rugged, able to withstand conditions of heat, cold, dry, and wet that mold colonies would not be able to handle. 

The spores are extremely small and light, and measure roughly 10 to 30 microns. To put that into perspective, human hair can be as large as 300 microns. Mold spores are so small that even the slightest air current can send them traveling for miles. Spores can land anywhere, and when they land on a damp surface, they are able to become full-grown mold.

Wherever you find decaying organic matter, you will likely find mold. Piles of wet leaves in the fall are a prime example of the perfect mold habitat. We don’t mean to frighten you, but when you step outside, you are stepping into a world of mold.

While you can’t do anything for the outdoor mold, you can create an indoor environment that does not welcome mold growth. Mold is all around us, but high concentrations can cause significant health problems, which is why keeping mold from growing indoors is always important.

What are the Different Types of Mold?

You might assume that all mold is the same. But mold, like all life forms, is incredibly diverse and comes in many different shapes and colors. Like birds, bugs, fish, and mammals, there is a diverse range of life in the mold family tree.

Here are a few types that are a particular concern for homeowners.


This type of mold grows extremely well on wood, hay, paper, and cardboard. This is the type that is commonly called “black mold” or “toxic mold” although these are unofficial terms that are often used to describe different molds. Stachybotrys mold usually requires extremely damp conditions with days or even weeks to fully grow.

Toxic molds, also known as mycotoxins, can also be found in office buildings. We see this in offices with poor ventilation and indoor water source like a fountain. While water indoors may look pretty, if there is not proper ventilation as well as temperature and humidity control, it can be a breeding ground for black toxic mold.


Aspergillus mold is one of the most common forms of household mold. It has 185 different sub-species (we told you mold was diverse!), with 22 sub-species known to cause illness.


This is also a common form of mold that has a pretty ugly reputation. It has been blamed for skin lesions, nail fungus asthma, and lung infections.


This type of mold is actually common in soils, but it can work its way into homes. Mucor mold is often found in duct work and inside air conditioning systems. It grows fast, has a whitish or grey color, and can grow quite thick.

Penicillium Mold

Anyone who’s studied medicine knows that penicillin is commonly used as an antibiotic against various types of infections. It can grow on walls and many types of food, and it’s actually used quite often in food processing.

However, when this mold known as Penicillium grows in the home, it can cause medical issues, so it’s a useful mold that can also be a health threat.


This mold can be particularly troublesome because it creates potent toxins that have the ability to damage immune systems, organs, and bone marrow. It’s even been linked to potential problems with mental abilities.


This is another common soil mold that usually affects humidifiers and plants. It can produce toxins that could be harmful to circulatory and nervous systems. If this mold does affect someone, it’s usually through ingestion (such as eating contaminated grains), but it is not unheard of for people to inhale the spores and have problems as well.

What Factors Increase the Risk of Mold?

Mold needs a very specific environment to grow, but it is resilient and, once it finds the right environment, can grow quickly.

It can also be difficult to remove under the right conditions. In those cases you may need to consider a mold remediation expert. 

As we discussed above, the first thing mold needs is a damp environment; without water, mold, like other life forms, cannot grow.

Unfortunately, mold can grow with a tiny amount of moisture. It also needs a food source, which it can find from wood, dust, drywall, cotton, and many other materials.

Mold also needs darkness.

Mold has a difficult time growing in direct sunlight, because UV rays are harmful to the spores and cells of mold. For this reason, mold is often found in basements and hidden locations, well protected from the harmful effects of UV light. (We’ll elaborate on UV light and mold below.)

It will also need an ideal temperature. Mold spores can survive in a wide temperature range, from just above freezing to roughly 120 degrees Fahrenheit. The mold colony itself, however, needs a much narrower temperature range.

Unfortunately, this temperature is almost the exact same range that humans find comfortable: about 60 to 90 degrees Fahrenheit. Mold can also lay dormant during freezing temperatures.

These factors (water, food, temperature) are the three basic elements that mold needs to thrive. If you can limit or eliminate one or more sources, you’ll go a long way towards preventing mold in your home.

Limiting temperature is, for all intents, impossible (unless you want to live in a cold or hot house). So, limiting available food and water (especially water) becomes the most workable solution.

Mold and Your Health

When we discuss air quality and health, on any subject, we always make sure to reference authority organizations and cite the most important scientific and medical studies possible. With that in mind, let’s look at some important information on mold and how it can affect the health of you or your family members.

According to the Centers for Disease Control, mold can cause symptoms such as “nasal stuffiness, throat irritation, coughing or wheezing, eye irritation, or, in some cases, skin irritation” in people who are sensitive to the mold spores. If people have allergies, there can be severe reactions. For people with compromised immune system, serious infections are always possible.

A review of medical information published in Environmental Health Perspectives, looked at results from multiple studies on dampness, mold, or microbiological agents and the connection to respiratory health and mold allergies. The review concluded that as dampness and mold increase, so do allergic symptoms and respiratory effects.

There is also speculation that mold can have other effects, but these mostly remain unproven or unfounded. There are theories that mold can contribute to memory loss and diseases among infants, but as of now these are basic theories with little to no scientific evidence.

However, the clear connection between mold and respiratory health is significant enough to warrant preventative measures, as well as rapid removal if mold becomes present in your home.

Mold Prevention: Preventative Measures

The first step you should take is to keep mold of all types from ever finding a place to grow in your home. As you probably realize, this starts with controlling dampness and humidity levels.

Use a Dehumidifier

One of the common tools for controlling humidity is a dehumidifier. These appliances trap airborne moisture and collect it in small tanks, which can then be emptied manually. Some models even have hose connections, allowing the water to flow to nearby drains. This reduces the amount of time and effort you have to put into using a dehumidifier. Sources like WebMD even recommend the use of a dehumidifier to prevent mold growth.

When using a dehumidifier, aim to keep humidity levels below 60% for the best mold prevention; this can be measured with a convenient tool called a hygrometer, which can be purchased at most home improvement stores. Always keep the dehumidifier’s pan and hoses clean, and make sure drain lines are free of obstructions for the best results. 

Clean Wet Areas

It’s important that you clean up wet areas as quickly as possible to prevent mold growth. Don’t allow water to sit on the floor of the kitchen or bathroom, as this can increase the likelihood of mold and create a potential safety hazard.

Fix Seepage and Leaks

Preventing water from entering the home, especially in the basement, is vital. Take measures to seal the home from moisture, and repair any cracks in the foundation that allow water to enter. Don’t let leaky pipes drip for too long, and make sure connections to appliances and sinks are fully sealed.

Increase Ventilation

Open windows, open doors, and running fans, can increase the air circulation in a home, which will reduce the chances of mold. Of course, this depends on the weather conditions outside as well as air quality concerns such as pollen, dust and air pollution.

Run the Bathroom Fan

The bathroom is one of the most common places for mold. If it weren’t for basements, it would be the undisputed #1 location for mold growth.

However, you likely have an important tool for combating mold that you may not have thought about. The ventilation fan at the ceiling is not just for removing odors, it can also be used to increase circulation and reduce moisture levels.

Use Mold-Resistant Products

This is obviously a more intense step, but if you are remodeling, adding a wing to the home, or building a new house, use mold-resistant materials wherever possible.

For example, use mold-resistant drywall, which is gypsum plaster covered with fiberglass instead of paper. This eliminates the nutrient source for mold. It also makes the drywall moisture-resistant, furthering the material’s anti-mold characteristics.

Landscape Away from the Home

Water needs to be directed away from the home to reduce the chances of basement seepage and dampness. Inspect the outside perimeter of your home to see if there is any sloping into the foundation. Better yet, wait for a heavy rain, then see if there are puddles around the foundation.

If so, either hire someone to fill in the landscaping or do it yourself. This will prevent water from pooling at the side of your house and eventually seeping into the basement.

Use an Air Purifier

With proper air flow and a high-quality air filter, an air purifier can become one of the best tools for keeping mold from affecting your home.

Using high efficiency air filters, air purifiers can remove the airborne mold particles as well as other particles that are much smaller than mold spores. They can also remove dust, pet dander and other potential sources of indoor mold growth.

Air Purifier Note: Use UV Light Air Purifiers to Destroy Mold Spores

Before we dive into mold removal, it’s important that we discuss one of the most effective technologies for mold removal: UV light. Air purifiers that use UV light pull in air and move it through a chamber that exposes it to UV light. The light breaks down the DNA of a mold spore, making it ineffective for creating new colonies.

Mold Removal: What to Do When You Find It

If you discover a serious mold problem in your home, you will want to take significant measures to completely remove it. Depending on the problem and the location, it may be necessary to hire a professional mold remediation team.

It is possible, however, to remove it yourself...

A bleach solution is commonly used to remove mold. Bleach contains chemicals that destroy the proteins of mold, and can be effective for removing mold, as well as the stains it can leave behind. However, you must use extreme caution when using bleach; if you’re not 100% sure on proper mixtures and solutions, always hire a professional.

Vinegar is another liquid that can kill mold. Distilled white vinegar applied to nearly any surface can kill mold because of the vinegar’s acid levels. This is a natural and non-toxic option, and can even help mold from growing in the future. However, it is not as strong as bleach or commercial mold-cleaners.

Hydrogen peroxide, borax, and many other household products can also be used to remove mold, but in some cases, it may be necessary to hire a professional. If you choose to go with a professional, make sure you get multiple quotes and have a clear understanding of the work that will be done.

Choosing the Right Air Purifiers for Mold Allergies and Prevention

Air purifiers can be a powerful tool to prevent mold growth and reduce mold allergy symptoms. By trapping or killing mold spores, an air purifier makes it harder for mold to grow in a home or to be breathed in.

So, what are the best options?

Fortunately, Oransi has top-quality purifiers for you to choose...

mod+ Air Purifier

The mod+ air purifier is rated to clean rooms measuring 1,361 square feet with two air changes per hour, which means it is perfect for large home living areas, offices, healthcare facilities, and spacious basements. It’s so powerful that it is a common choice for mold abatement. Despite its power, it is extremely quiet. We also offer a small option in the mod jr. air purifier that is just like the mod but cleans 878 square feet with two air changes per hour. 

Find the Perfect Air Purifier for Your Home with Oransi

Whether you are looking for an air purifier that can remove mold spores or eliminate pet dander, Oransi has the perfect items for your home.

With a full inventory of top-quality products, you’ll find everything you need when you order your air purifier from Oransi.

You’ll not only have leading air purifiers, you’ll have convenient access to all the right filters and accessories for excellent long-term performance!