What influences the level of humidity?
Indoor humidity constantly changes due to weather, ventilation, heating systems, production processes, and occupancy. When humidity becomes too high or too low, it can affect product quality, employee comfort, static electricity, mold growth, and energy consumption. Understanding what influences humidity is the first step toward creating a stable indoor environment.
- What is relative humidity?
Relative humidity is the amount of water in the air compared to the maximum amount the air can hold at that specific temperature. It is shown as a percentage. A reading of 100% means the air is completely full of moisture, while 0% means the air is totally dry. For example, during winter time people often experience issues with low humidity indoors. This is because the buildings are heated up. And warm air can hold much more moisture than cold air. So when the cold air from outside enters a building the relative humidity level drops, since no additional moisture is added.
This is what a room with 100% RH looks like
There are many factors which have influence on the RH
- Ventilation
The level of ventilation in a building can impact indoor humidity. Proper ventilation allows for the exchange of indoor and outdoor air, which can help control humidity levels. Inadequate ventilation can lead to higher humidity as moisture becomes trapped indoors, while excessive ventilation in very dry conditions can result in lower humidity.
- Temperature
As mentioned earlier, temperature plays a role in humidity. When the indoor temperature increases, the air’s capacity to hold moisture also increases, leading to lower relative humidity. Conversely, lower temperatures reduce the air’s moisture-holding capacity, resulting in higher relative humidity. This is why humidifiers are especially important during winter time.
- Air conditioning and heating systems
HVAC systems can influence indoor humidity levels. Air conditioners extract moisture from the air as part of the cooling process, leading to lower humidity. However, some modern air conditioning systems also include features to control and maintain desired humidity levels. Heating systems, such as forced-air systems, can dry out the indoor air, lowering humidity levels.
- Building insulation
The level of insulation in a building affects the exchange of indoor and outdoor air. Well-insulated buildings are more airtight, which can trap moisture indoors and potentially lead to higher humidity levels. Insufficient insulation may result in higher humidity as outside moisture can penetrate the building.
- Occupancy
The number of employees and their activities in a building can impact indoor humidity. People release moisture into the air through respiration, perspiration, and other daily activities. A crowded space with high occupancy can raise humidity levels.
- Humidifiers and dehumidifiers
The level of insulation in a building affects the exchange of indoor and outdoor air. Well-insulated buildings are more airtight, which can trap moisture indoors and potentially lead to higher humidity levels. Insufficient insulation may result in higher humidity as outside moisture can penetrate the building.
- Outdoor weather
Outdoor conditions have a significant influence on indoor humidity. Seasonal changes, rainfall, temperature, and wind all affect the amount of moisture entering a building. This is why humidity levels often fluctuate throughout the year unless an active humidity control system is used.
Recommended humidity levels per industry:
- Automotive: 50-60%
- Bakery: 40-60%
- Chicken hatch: 60-70%
- Electronics: 30-70%
- SMT: 30-50%
- Greenhouse: 40-70%
- Mushroom cultivation: 80-90%
- Printing: 40-60%
- Textile: 40-60%
- Wine cellar: 50-60%
Signs your humidity level is too low
- Static electricity
Static electricity is one of the most common signs of low humidity, especially during winter. When the air is dry, electrical charges cannot dissipate easily, causing static to build up on people, products, and equipment.
In industrial environments, static electricity can:
- Attract dust and contaminants.
- Cause products to stick together.
- Disrupt automated production lines.
- Damage sensitive electronic components.
- Create uncomfortable shocks for employees.
Maintaining the correct humidity significantly reduces static build-up and improves process reliability.
- Dry products
Many materials naturally release moisture when the surrounding air is too dry. As a result, products may shrink, crack, warp, or lose weight.
Examples include:
- Wood products developing cracks or warping.
- Paper curling or shrinking.
- Textiles becoming brittle.
- Food products drying out and losing weight.
- Fresh produce losing moisture.
- Mushrooms becoming dehydrated.
Stable humidity helps preserve product quality and reduces waste.
- Dust becomes airborne
Dry air allows dust particles to remain suspended for longer periods instead of settling. This creates a dustier working environment and increases cleaning requirements.
Excessive airborne dust can:
- Contaminate products.
- Reduce indoor air quality.
- Increase equipment maintenance.
- Affect employee health.
- Increase the risk of combustible dust hazards in certain industries.
- Cracking or warping of materials
Many hygroscopic materials absorb and release moisture depending on the surrounding humidity. When the air becomes too dry, these materials lose moisture and may change shape.
Materials affected include:
- Wood
- Paper
- Cardboard
- Leather
- Textiles
This can lead to dimensional changes, reduced product quality, and increased rejection rates.
- Dry skin, eyes, and respiratory irritation
Low humidity not only affects products but also employee well-being. Dry indoor air can remove moisture from the skin and respiratory system, causing discomfort throughout the workday.
Common symptoms include:
- Dry skin.
- Chapped lips.
- Dry or irritated eyes.
- Sore throat.
- Dry nasal passages.
- Increased susceptibility to respiratory irritation.
Maintaining an indoor humidity between 40% and 60% RH generally provides a more comfortable working environment.
- Product quality issues
Many manufacturing processes require stable humidity to achieve consistent results. Low humidity can lead to product defects, reduced yields, and increased scrap.
Examples include:
- Uneven printing.
- Static problems in electronics manufacturing.
- Drying of adhesives or coatings.
- Cracking of pharmaceutical tablets.
- Dehydration of food products.
- Poor performance during textile processing.
Maintaining the correct humidity improves product consistency and production efficiency.
Control your humidity levels precisely with the Japanese technology, AKIMist®
- Humidifying with water without wetting equipment (no water drops)
- Prevents static electricity at production site
- Easy installation by adding on to existing HVAC
- Easily adaptable to changes in the floor layout
- Its double advantage of cooling while humidifying
- Reducing product loss and scrap
- Improving product quality
- Low maintenance
Download our catalog to learn more about the techology behind AKIMist® and Dry Fog
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