Does UV Light Kill Mold?

UV light in home to kill bacteria and mold.

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Mold is not something anyone wants to have in the home. It can cause health issues and also spreads fast. Sometimes homeowners will use ultraviolet germicidal irradiation (UVGI) cleaners to destroy biological pollutants such as bacteria, viruses, and other molds. The molds it will kill are usually on HVAC surfaces. Since UVGI cleaners work well in other parts of the home, often homeowners wonder, does UV light kill mold? No, it doesn’t kill molds and bacteria in the home as it needs higher UV exposure than what is in most home units.

Let’s take a look at UV light.

UV light on hands to see if they are clean and free of bacteria.

What Is UV Light?

Ultraviolet germicidal irradiation (UVGI) is used in hospitals to kill bacteria, and inside ductwork in a home to avoid the spread of mold. Additionally, it is used in some water systems in homes to kill bacteria in the water. UVGI lamps use ultraviolet light which is the same light that is found in the sun. The purpose of UV light is the penetrate the cells of the mold or bacteria and eliminate its DNA. In doing so, the cell can no longer function or reproduce. The cell has no choice but to die and be removed.

How Does UV Light Kill Bacteria?

When it comes to killing bacteria there aren’t a lot of options. Let’s take a look below at what UV light can do to kill bacteria.

  • How they work – UV lights will send a short wavelength of energy to penetrate the mold. This light then destroys the DNA inside of the mold spores which inactivates the mold spores.
  • UV light direct – To completely destroy the mold or bacteria that you are pinpointing, you will need to place the UV-C light directly onto the mold or bacteria areas.
  • Install one – You can install a UV light inside of your HVAC system as part of the system. While mold spores dance around your air ducts, the UV lamp will ensure that they are killed.
  • Keep away from you – UV lights can be harmful to any homeowner. Be sure not to expose your eyes or skin to UV light while using one.

How Does It Work?

UV lights work in various ways to kill mold and bacteria. Keep in mind that not all UV lights have the capability of wiping out mold spores. In many cases, UV light systems are best used in HVAC and water filtration systems. Spot-killing mold or bacteria can be done by putting on your UV-protective goggles, turning off all other lights in the home, and using your UV lamp. Shine the UV lamp directly onto the mold and let it sit for two hours. Then change the angle of the UV light so that all areas of the mold get a dose. Consequently, you will want to repeat these steps for every area of the home that has mold. Additionally, you will need to run an air filtration system in the area where you are killing the mold spores. This system will trap and dispose of all dead mold spores.

Cons of Using UV Light

Just because UV light can assist in killing some mold spores and bacteria does not always mean that it is the best choice. Let’s take a look at what some of the negative reasons for using UV light might be.

  • Direct contact – The UV light must come into direct contact with the mold spores in order to actually kill them. This could cause the light to miss any deeply tucked away mold spores in areas with a porous surface, such as drywall.
  • Cost – To Install a UVGI system to cover an entire room could cost you as much as $9,000 or more. Also, consider that spending $100 on a small UV-light lamp, might not be a great idea as it only covers a small area. Consequently, this could be time-consuming.
  • Dangerous – UV light usage can be dangerous to any homeowner. It is an artificial light that can cause extreme burns if exposed to the skin. Also, if pointed in the direction of your eyes, it could cause blindness.
Mold spores are dangerous to your health.

Other Ways to Get Rid of Mold

Now that you know about UVGI treatment, there are other ways to get rid of mold. If you have a flood or a leak, you may need to throw away insulation, furniture, carpet, or porous materials that end up with mold on them. You may be able to reach out to a mold remediation specialist to save these items. Unfortunately, porous surfaces are difficult to remove mold and you may have to part with these items.

If you are trying to get the mold off a surface, you can spray white vinegar on the mold and then let it sit for an hour. However, make sure you don’t put the vinegar on stone or wood countertops. If you find it doesn’t clean easily, you can also use 1 teaspoon of baking soda mixed with 2 cups of water. Do this in a spray bottle. Then, spray this concoction on the area and use a stiff brush to wipe it. After you scrub it well, take warm water to rinse the area and let it dry. Once it has dried spray again, but this time just with white vinegar and allow it to dry. Letting it dry instead of rinsing it will let it work on any spores that remain and prevent regrowth.

Other Recommended Maintenance

Now that you know more about UV light, let’s take a look at some other areas of maintenance. One of those is mold on the pool deck. If you find that black mold is showing up, you can use bleach, a scrub brush, water, a pressure washer, and a vacuum to clean it. To avoid this in the future, you can seal the patio or deck and this should help.

Another one is the accuracy of air mold tests. If you have a musty smell in the home, it is a good idea to start with an air mold test. Then, you can find out from a professional the levels of mold in the home. it is important to find out this information for the sake and safety of the people in your home.

Lastly, if you are buying a home and you order a home inspection, it is good to know that home inspectors check for mold. They do a visual inspection and sometimes may do mold sampling. If there is mold, work with your local inspection company to remedy the problem.

When Do I Call A Professional?

Anytime you are dealing with mold spores you will want to reach out to a professional mold remediation team. If you aren’t sure how to access a mold remediation team, reach out to your local home inspection team. They can conduct a mold inspection of your home during a full home inspection. Also, they can refer a reputable mold remediation team to assist with any necessary mold removal.


Homeowners that deal with mold removal on their own are risking some serious health issues. It is best to reach out to professionals for mold removal. There are a variety of toxic molds out there and attempting to remove them from your home could stir up the mold spores into your air. Doing this could cause some major health issues in your home. Call on your local home inspection team to conduct an air quality and mold inspection in your home. Reach out to Fox Mountain Property Inspections for a mold and air quality inspection during a full home inspection in Maryland, Pennsylvania, Virginia, and West Virginia states.

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