Maintaining an ideal indoor humidity level is essential to ensuring the best performance from both building systems and occupants. More often than not, building conditions don’t fall within the optimal humidity range. So, what can facility managers do to get within this level?
The ideal indoor humidity level
Experts have long recommended maintaining indoor relative humidity between 40% to 60%. However, research shows commercial buildings’ levels often fall somewhere outside of this range. In one study, office buildings were below the minimum threshold around 42% of the time and above the maximum threshold 7% of the time during weekdays.
When humidity levels are too low or too high, facility occupants often experience discomfort. They might experience symptoms varying from sore throats to excessive sweating. Prolonged exposure to inadequate humidity levels may adversely affect their well-being, reduce their productivity, and make them vulnerable to illnesses. As a result, the facility’s absenteeism rate will eventually increase.
Conversely, keeping the humidity level within the 40% to 60% range can improve peoples’ well-being. Research shows hydrogen peroxide—a naturally occurring disinfectant agent—can spontaneously form in microdroplets of water. Its concentration increases by a factor of around 3.5 as the humidity level increases from 15% to 50%.
Ensuring buildings maintain the ideal indoor relative humidity level is not just about occupant comfort—although that should be a priority for any facility manager. If decision-makers ensure humidity levels remain within the acceptable threshold, they can manage condensation, indoor air quality, and structural integrity.
Optimal humidity reduces building equipment wear, allowing electrical, plumbing, and HVAC units to consume less energy and operate more effectively. In addition to improving equipment performance, optimal humidity can reduce the likelihood of premature equipment failure, extending systems’ life spans.
Facilities often exhibit numerous clues when they deviate from the ideal indoor humidity range.
Signs of high humidity
When a facility rises above 60% relative humidity, adverse effects are inevitable. Structural damage becomes increasingly likely as time passes. Adhesives degrade, paint bubbles, and wood swells. Sweating slab syndrome—a phenomenon that occurs when condensation builds up on the floor’s surface—can cause foundation issues. Moreover, it creates a slip-and-fall hazard.
Energy efficiency diminishes as building systems work harder to compensate for elevated wear. For example, condensation can corrode an HVAC unit’s evaporator coils and condenser fan blades, causing leaks or even premature equipment failure.
Even if levels are only slightly above the acceptable range, microorganism growth is a possibility. Warm, humid environments encourage mold, pathogenic bacteria, and dust mite proliferation. If these issues go untreated for too long, they spread from the source. Merchandise, furniture, walls, and ceilings will quickly become contaminated.
Signs of low humidity
The effects of high indoor humidity are often visible to occupants and therefore frequently prioritized. However, low humidity levels can be just as damaging, causing wood to crack, adhesives to dry out, and paint to chip. While the type of damage varies between humidity extremes, both will accelerate the wear of building materials.
Anything below the ideal indoor humidity range encourages the movement of viruses, bacteria, and dust particles. Without water microdroplets to weigh them down, these air pollutants become airborne and circulate through the HVAC system more easily, worsening indoor air quality.
There’s also the risk of electrostatic discharge, which may damage electronic systems, rendering them inoperable. Typically, wet surfaces are more conductive than dry surfaces. However, the lack of moisture in the air allows electrostatic charges to accumulate, increasing the risk of electrostatic-induced equipment failures.
Top causes of humidity issues
Common causes of humidity problems in commercial buildings include the following:
- Poor ventilation: Over- or under-ventilation is a common cause of humidity issues. Since less than 10% of facilities have building automation systems, it is up to managers or service contractors to manually adjust systems as needed. Unfortunately, this allows room for human error.
- Water leaks: When leaks spring from roofs, plumbing fixtures, or HVAC systems, the relative humidity level increases. Unless managers have monitoring technologies installed or receive timely reports from custodial professionals, issues can remain hidden in the walls, ceilings, or floors for weeks.
- Inadequate sealing: Regardless of whether sealing was improperly installed or has degraded over time, inadequate sealing can force a commercial building outside of the ideal indoor humidity range. If too dry or too humid air from outdoors makes its way inside, it will mingle with the air inside, disrupting the balance.
Methods to optimize the humidity level
Before optimizing indoor humidity, management should take preventive measures to protect facility equipment. For example, using cable isolators can protect sensitive electronic equipment from electrostatic discharge caused by low humidity. These components can withstand temperatures ranging from -300°F to 500°F, so minimal upkeep is required.
Mitigating equipment damage, electrostatic discharge, structural damage, and air pollutant circulation as soon as possible is ideal. By addressing pressing issues immediately, managers gain more time to perfect their optimization strategy.
Leveraging devices like internet-connected sensors and smart thermostats allows for remote, real-time monitoring. Moreover, these technologies are often more energy efficient. For instance, facilities can achieve a 90% energy consumption reduction after switching from a conventional humidifier to a smart version.
At the very least, building service contractors (BSCs) should routinely inspect HVAC systems, as they can easily become reservoirs for mold and bacteria. If the issue goes unaddressed for too long, mold spores or air pollutants can spread throughout the building.
The bottom line on humidity level optimization
Facility managers and BSCs must work together to proactively mitigate humidity-related issues and achieve and maintain an ideal indoor humidity level. By doing so, they can enhance the facility’s performance while contributing to the safety and health of its occupants.
