Mold growth is a common problem that many homeowners face. Excess moisture in the air allows mold spores that are naturally present in any environment to germinate and grow, forming visible colonies. Indoor mold can cause a variety of health problems, especially for people with allergies or asthma. It can also damage building materials and furnishings. Controlling indoor humidity levels is crucial for preventing and eliminating mold. A dehumidifier is an effective tool to reduce moisture and inhibit mold growth. In this blog post, we will discuss tips on using a dehumidifier properly to rid your home of mold and prevent future outbreaks.
How Mold Grows
Mold is a type of fungus that produces microscopic cells called spores as its means of reproduction. Spores are very tiny, measuring only 2 to 10 microns in size. To give some perspective on how small that is, the diameter of a human hair ranges between 17 to 181 microns. These tiny spores travel easily through the air and are found everywhere, both indoors and outdoors. When the spores land on a damp surface, they can germinate and develop into mold colonies which are comprised of filamentous branches and roots.
Mold needs moisture to proliferate. Indoors, some sources of moisture that can facilitate mold growth include flooding, roof and plumbing leaks, high indoor humidity, damp basements, moisture condensation on windows, walls or pipes and all wet building materials. Ideal relative humidity levels for occupants are below 60%. But mold will thrive at humidity levels exceeding 70%, especially if the moisture persists for over 48 hours. Cellulose-based materials used in construction like wood, drywall, fabrics, carpets and insulation are very vulnerable. Mold can even grow on dust, dirt and lint accumulations if they become damp. Controlling moisture is the key to inhibiting mold growth.
Health Effects of Mold Exposure
Some people are more sensitive to mold than others. Allergic reactions are common, especially among those with asthma or other respiratory conditions. Symptoms may include nasal congestion, dry, itchy throat, wheezing, coughing, burning or watery eyes, headaches and fatigue. People with weakened immune systems are at higher risk for opportunistic infections from certain toxic molds like Aspergillus. Prolonged exposure has also been linked to upper respiratory tract symptoms, even in non-allergic persons. Some studies suggest molds may exacerbate asthma and contribute to development of asthma in susceptible children. Although more research is needed, there are concerns mold exposure may be associated with other inflammatory illnesses affecting the lungs, skin and nasal cavities. Monitoring and maintaining safe, low humidity levels helps minimize mold risks.
How Dehumidifiers Control Moisture
Dehumidifiers work by drawing moist air into the unit using a fan. The air passes over cooled metal coils which cause the moisture to condense, much like what happens to a cold glass on a humid day. The water droplets run down the coils into a collection reservoir while the cooled dry air recirculates back into the room.
The capacity of the dehumidifier, measured in pints collected over a 24 hour period, must be properly matched to the size of space being dehumidified. Large capacity dehumidifiers often have a humidistat built in to automatically regulate moisture based on the relative humidity setting. Various features like auto shut off when the reservoir is full or when the target humidity is reached add convenience. Many units have settings for continuous operation if needed in damp conditions.
Tips for Using a Dehumidifier Against Mold
Here are some key tips for using a dehumidifier to eliminate an existing mold issue and prevent future outbreaks:
- Size the capacity appropriately – Choose a dehumidifier adequate for the total square footage of the area being treated. As a rule of thumb, medium to large capacity units (45-85 pints/day) work best for home use.
- Select the proper location – Place the dehumidifier in a central area where air circulates well. For whole home protection, a basement installation near the furnace may be ideal to treat air as it enters ductwork.
- Clean all moldy surfaces – Thoroughly clean any visible mold with detergent and water. Scrub porous materials like drywall to remove root threads. Dry all areas quickly and completely.
- Discard moldy porous items – Dispose of any materials like drywall, insulation or soft furnishings that remain damp or have mold damage after cleaning. Mold roots can re-grow in porous substances.
- Run the dehumidifier continuously – To eliminate existing mold, initially run the unit continuously 24/7 on high fan speed if possible. This rapidly draws moisture from the air and building materials.
- Use exhaust fans – Run kitchen and bathroom exhaust fans, especially during cooking or showering, to vent moist air outside. Keep closet and cupboard doors open to improve circulation.
- Aim for relative humidity of 45-50% – Use a humidistat or hygrometer to monitor progress lowering humidity. Reduction to 45-50% relative humidity inhibits mold growth.
- Maintain lower humidity – Once mold appears eliminated, maintain relative humidity below 60% to prevent re-growth. During humid seasons or in damp climates, continual dehumidifier use may be needed.
- Check for water leaks – Detect and repair all plumbing and roof leaks, especially in basements or crawlspaces. Use vapor barriers and insulation to reduce dampness from condensation.
- Improve air circulation – Open blinds/curtains to allow sunlight in. Move furniture away from exterior walls. Ensure adequate ventilation from outdoors.
- Clean and disinfect the dehumidifier – Follow manufacturer directions to keep the unit clean. Dirty filters or coils reduce efficiency. Clean the collection tank regularly to avoid reintroducing mold and other allergens into the air.
- Consider other moisture-control equipment – For serious, ongoing moisture problems, consider installing whole-house ventilation, central HVAC air scrubbers or commercial dehumidification equipment.
How To Use A Dehumidifier To Eliminate Mold
A dehumidifier can begin to eliminate mold after running continuously for 24-48 hours. The reduced humidity inhibits further mold growth and over several days active colonies will die off as moisture levels remain too low for mold to thrive. Expect 1-2 weeks of continuous dehumidifier use at proper humidity levels to fully kill off mold.
How Do You Use A Dehumidifier Properly?
To use a dehumidifier properly, size the unit correctly for the space, select a central location with good air circulation, set the humidity level between 45-55%, run it continuously during initial drying and mold removal, then maintain lower humidity levels ongoing to inhibit mold growth. Also regularly clean the unit and empty the water reservoir.
What Should A Dehumidifier Be Set At To Prevent Mold?
To prevent mold growth, a dehumidifier should be set to maintain relative indoor humidity below 60%, with an ideal target between 45-55%. This humidity range deprives mold of the damp conditions needed for proliferation.
Should A Dehumidifier Run Constantly?
A dehumidifier should run constantly, 24 hours a day, when first being used to eliminate existing mold. Continuous operation rapidly pulls moisture from the air and building materials to dry out the area. Once mold is removed, the dehumidifier can cycle on and off to maintain lower humidity levels for prevention. Units with humidistats simplify maintaining optimal humidity.
Does A Dehumidifier Help With Black Mold?
Yes, a dehumidifier can help eliminate black mold by lowering humidity below mold growth thresholds. Reduce relative humidity to 45-50% and run continuously for 1-2 weeks to kill black mold. However, any visible black mold should first be cleaned using protective gear as it is toxic. Seek professional mold remediation if infestation is severe.
When to Seek Professional Help
While home dehumidifiers can effectively manage moisture and mold for typical residential situations, it is wise to contact professionals for the following scenarios:
- Extensive visible mold colonies exist, especially if you have health conditions making you more vulnerable to mold. The remediation process to remove large infestations requires special protective gear and containment protocols best handled by mold remediation specialists to prevent spore dispersal during cleanup.
- You experience recurring mold outbreaks during humid seasons or in damp basements that consumer devices cannot control sufficiently. Commercial dehumidification systems may be needed.
- The source of moisture is a substantial roof leak, flooding, sewage backup or other catastrophic water damage. Water extraction, repairs or mitigation should be done by qualified contractors.
- HVAC inspection determines your ductwork is contaminated with mold. Thorough duct cleaning will be required.
- You wish to test for specific mold species, especially if concerned about toxic varieties. Professional sampling can identify the type of mold present. This also provides documentation should health issues emerge.
- There are doubts about how far mold has spread into building cavities or materials. Contractors have equipment such as boroscopes and infrared cameras to inspect behind walls and into insulation. Swab or air testing can also detect mold not visible.
For many homeowners, using a well-sized dehumidifier conscientiously can successfully tackle routine moisture control and minor mold outbreaks. But do consider consulting mold abatement experts for any large infestations or if health concerns exist. With proper humidity management, your home can stay mold-free.
For professional mold remediation around North and Central Georgia, contact Southeast Water Restoration immediately!