Humidity Levels and Mold Growth

High Humidity Causes Mold Growth

Humidity, Dew Points, and the Myrtle Beach Climate

In order to understand the relationship between humidity levels and mold growth, we first need to understand that our South Carolina climate is considered "muggy" for 5.2 months of the year. If you live here, this is no surprise. You can sum up a Myrtle Beach summer in two words: hot and humid.

We typically measure humidity with what's known as the "Dew Point." The dew point, simply, is the temperature at which water vapor condenses into liquid water. The dew point is a good indicator of how much moisture is in the air. In Myrtle Beach, lower dew points occur in the winter and higher, "muggier" days make up most of the weeks from May-October. Muggy weather, or weather with a high dew point, makes it easier for mold and mildew to grow.

Conditions for Mold Growth

Mold spores live and grow on and in organic material. Around your home this may be wood, carpeting, insulation, or paper. These organic materials are the "food" source for mold. Mold growth is not just a respiratory and health problem, it also can slowly destroy the structural integrity of walls, framing, and flooring.


While there are some molds that can thrive in cold temperatures, most mold thrives in warm, moist areas. For this reason, indoor mold growth can run rampant, especially in hot, sticky areas like an attic or a poorly ventilated room.


If mold spores grow and spread in these areas, a professional mold removal service is required. After successful remediation, the best way to prevent returning mold is to control indoor humidity and ventilation.

Signs of High Indoor Humidity and How to Control It

Indoor mold growth is often a clear sign of indoor humidity, but you may see other signs as well. Indicators of high indoor humidity include:


  • Condensation on windows, walls, and around plumbing
  • Mildew on kitchen or bathroom surfaces
  • Feeling sticky and uncomfortable indoors


High indoor humidity (and resulting mold growth) often means your HVAC system is inefficient. After mold removal by a professional service like MasterTech Environmental of Myrtle Beach, you'll want to work with an HVAC company to address humidity, ventilation, and air circulation concerns.


As a result, using portable dehumidifiers are a good temporary solution. Used in poorly ventilated and humid rooms, dehumidifiers are inexpensive tools that will remove excess moisture from the air. Although this may take some of the work off your HVAC systems plate, it's a temporary solution if the cause is poor air flow.

Take Care of Humidity Levels and Mold Growth This Summer

MasterTech Environmental of Myrtle Beach is your locally-owned and operated mold removal specialist on the Grand Strand. Let our team wipe out your mold problem and find solutions that address the causes of humidity levels and mold growth.

Mold inspection in Myrtle Beach
By Jonathan Smith September 26, 2025
Schedule a professional mold inspection in Myrtle Beach and take back control of your air because protecting your family’s health and your home starts with finding what you can’t see.
By Jonathan Smith September 20, 2025
You smell something musty when the AC kicks on — is it coming from your attic? It’s unsettling when a wave of mustiness greets you every time your air-conditioning starts. The odor wafts from vents, yet looking around your living room reveals no visible problem. Eventually, you climb into the attic and find black and white patches on the roof decking and rafters. You may feel embarrassed for missing it, angry about the potential cost, and worried about what your family has been breathing. That mix of emotions is normal. Hidden attic mold often goes unnoticed because attics are rarely visited and because spores can travel quietly through ductwork. When mold establishes itself overhead, it isn’t just an eyesore; it becomes an air-quality issue for your entire home. Molds release spores whenever they are disturbed. An HVAC system that passes through or near a moldy attic can carry those spores into bedrooms and living spaces, exacerbating allergies and asthma. Any mold growth indoors indicates a moisture problem and needs to be addressed promptly. Attic mold remediation isn’t about cosmetic cleaning—it’s about eliminating a contamination source, fixing the underlying moisture and ventilation issues, and protecting your air ducts from becoming a delivery system for spores. How Attic Mold Enters Your Living Space Mold contamination in the attic rarely stays contained. The attic may be hidden above your head, but the pathways that connect it to your living space are surprisingly efficient. Airflow, ductwork, and even subtle pressure changes in your home can act as invisible highways, carrying spores downward where your family lives and breathes. Understanding these entry points shows why attic mold is more than an isolated issue; it’s a whole-house problem. Here are the most common ways attic mold infiltrates the rest of your home. · Supply and return ducts run through or near a moldy attic. Warm air traveling through cool, humid attic spaces can condense on ducts, creating wet spots where mold colonizes. Once mold grows on or near the ductwork, spores are easily pulled into the system and distributed to the rest of the house. · Negative pressure draws attic air downward. When bathroom fans or dryers operate, they can depressurize living areas, pulling attic air (and mold spores) into the house through small openings around light fixtures and access hatches. · Running a contaminated HVAC system spreads spores. If heating or cooling equipment is contaminated with mold, operating it can push spores throughout the building. Moisture and Ventilation Issues Are the Real Culprits It’s easy to blame mold itself for the problem, but mold is more of a symptom than a cause. The real enemy is moisture, and in the confined environment of an attic, even small amounts of dampness can create a breeding ground. Mold takes advantage of humidity, condensation, and leaks, thriving wherever water lingers longer than it should. Without addressing these underlying triggers, any cleanup is only temporary. The most common culprits behind attic mold include the following: · High humidity or inadequate ventilation. Warm, humid air trapped in an attic condenses on cooler surfaces. Blocked soffit vents, improperly vented bathroom fans, or missing ridge vents allow moisture to accumulate and keep attic lumber damp. · Roof or flashing leaks. Small leaks around chimneys, vents, or roofing materials provide direct moisture and can drip onto insulation and rafters unnoticed. · Poorly insulated ceilings or ducts. Temperature differences between conditioned living spaces and an unconditioned attic cause condensation on ductwork or the underside of roof sheathing, encouraging mold growth. · Long run times for undersized HVAC systems. Oversized fans running continuously re-evaporate water sitting on cooling coils and push moisture back into the attic and ducts. What Professional Attic Mold Remediation Does Differently DIY attempts often focus on surface-level fixes, such as bleach sprays or paint, but these solutions only mask the problem temporarily. Professional attic mold remediation is different because it treats the issue as a whole-house health hazard, not a cosmetic blemish. The process is carefully designed to protect your family during cleanup, remove contaminated materials thoroughly, and prevent mold from coming back. A trained remediation team follows a multi-step approach that includes: · Containment and protection of living areas. Professionals install physical barriers and negative-pressure units so that air flows into, not out of, the work area. This prevents spores from traveling to clean parts of the home. Simply painting over or covering mold is not an acceptable solution. · Removal and cleaning of contaminated materials. Technicians remove severely damaged insulation or duct sections, clean salvageable wood using HEPA-vacuuming and antimicrobial treatments, and may sand or dry-ice blast rough lumber to remove deep growth. · Addressing the root moisture problem. There is no lasting benefit to removal if humidity and leaks are not fixed. Professional remediators locate and repair roof leaks, correct ventilation deficiencies, insulate or encapsulate ductwork, and may recommend installing a dedicated dehumidifier. Attic Mold Remediation in Myrtle Beach: Protect Your Air Before It’s Too Late Mold in the attic is more than a hidden blemish; it’s a whole-house problem that contaminates your air every time the HVAC kicks on. We’ve seen how spores spread through ducts, how moisture and poor ventilation create the perfect breeding ground, and why surface-level fixes never last. Together, these factors turn a neglected attic into a serious health and structural hazard. The takeaway is simple: attic mold remediation isn’t optional or cosmetic — it’s essential. Professional containment, thorough removal, and moisture control protect your family’s health, preserve your home’s integrity, and prevent the cycle from repeating. So when that musty odor lingers, don’t dismiss it. It’s your home’s way of warning you. Act now, and secure cleaner air and a safer house with professional attic mold remediation.