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SanAir Technologies Laboratory, Inc.

AIHA accredited environmental microbiology laboratory, specializing in testing for asbestos, mold, lead & metals, and bacteria. Free overnight shipping.

What is the Difference between Mold and Mildew?

Man Examining And Repairing RoofMold and mildew are both types of fungi that are often found in homes. Humidity and excess moisture leads to their growth. They both spread easily and can grow on various surfaces. They must be treated during early stages to keep your house, furniture or clothing from being harmed.

In order to remove mold or mildew from your house, you must first identify which fungus is spreading. Many people get confused when it comes to differentiating between mold and mildew, but it is the first step that needs to be taken so that an appropriate remediation can be performed.

Mold vs. Mildew:

Mold is fungus with multi-cellular growth. It reaches below the surface of materials and affects them from inside. It can be seen near water leaks and leaking roofs, but it can be easy to miss when it is growing under the surface in an enclosed area. In these circumstances, it usually inflicts more harm as it only appears when enough damage is done already.

Mildew is a type of mold that grows on the surface of materials. It is easier to remove mildew because it grows on the surface. Scrubbing with an appropriate cleaner will remove mildew.

Physical Appearance:

Mold is divided into five categories and can be of black, green, yellow, white, blue, gray or brown colors. It appears fuzzy and can grow on plants, walls, floor, attic or roof.

Mildew is one of two types; downy and powdery. Powdery mildew is white or gray in color but gets yellowish brown with time. Downy mildew grows on agricultural items and ranges from yellow to brown. When growing on plants, they both appear as patches or spots on different parts of plants or trees.


Mold is capable of growing on both plants as well as other materials inside homes. It can damage the surface as well as the structure of a house if left untreated. Plants decay with time due to mold growth. To treat plants, either the affected branch needs to be removed or you may have to remove tree or plant entirely. 

Mildew is only found on plants, agricultural products, and crops. It is a parasite for which preventive measures must be taken in order to save attractive plants.

Health Effects:

Exposure to mold results in various health issues and needs to be treated early. It may cause depression, sinus infection, sore throat, pneumonia, allergies, skin problems, eye irritation, inflammation, extreme joint pain, respiratory problems, and migraines.

Mildew typically causes less severe problems including difficulty in breathing, cough, sore throat and headaches. 

Both mold and mildew may affect health of children, the elderly,  and those having weakened immune systems more severely than they do that of a normal healthy adult


Mold that grows outside the house is actually beneficial in many ways. It helps in returning the energy and nutrients from dead organisms back to the ecosystem. Certain types of mold fungi are used in the production of cheese, like blue cheese.  Due to its effectiveness in fighting bacteria, mold is also used to make some antibiotics and penicillin. Mold is also used in chemical industries to ferment organic acids.

If you see mold or mildew growth in your home you should seek the help of a professional. For help with air mold testing supplies and analysis, please get in touch with us today. SanAir Technologies Laboratory conducts sampling and testing of all hazardous materials present in your environment. Call us at 804-897-1177 or visit for further details.

SanAir Technologies Laboratory, Inc.