People spend over 60% of their lives indoors, making indoor air quality, including correct temperature and humidity levels, critical to personal health and comfort.
Without precise humidification management, school facilities that are air conditioned during the summer and heated in the winter are likely to struggle with sub-optimal humidity in the long run.
Continuous exposure to a humidity level below 40%RH will negatively affect the comfort and health of school staff and students. A high absence rate and decrease in productivity are common results.
Below the threshold of 40%RH, the most commonly known first effect of dry air is electrostatic shock. Further, less apparent symptoms can include dull hair, itchy skin, sore eyes and sinuses, contact lens discomfort and increasing dehydration. Maintaining optimal humidity levels, however, is proven to prevent these effects and furthermore decrease the danger of airborne viruses, such as influenza, transmitting in classrooms and office environments.
To protect human health and create a comfortable, productive environment the ideal humidity level lies between 40-60%RH. Installing industrial humidification systems within the central air conditioning system will ensure precise management and effortless maintaining of the ideal RH value. However, in-room humidifiers are an available option that can introduce moisture directly to a room's atmosphere.
Correct humidity plays an essential role in human health. Deviations from the mid-range of relative humidity (RH) of 40-60% decrease the quality of air substantially and can cause increased growth of bacteria, viruses, fungi and mites.Studies have shown that when the indoor RH drops below 40 percent, absenteeism due to illness increases. Conversely, if the air is too moist (above 60%), allergies and asthma increase due to the growth of fungi and mites.
Adequately humidified rooms feel warmer and immediately more comfortable. In colder climates where heating systems are a necessity this can make a big difference to one’s overall well-being.
The Sterling Chart – optimum RH for health
The Sterling Chart visually demonstrates the effect of RH levels on human health and comfort. Colds, flu, sore throat, dry eyes, itchy and cracked skin are well-known effects of low indoor humidity levels during the cold dry months of the winter. The increase in bacteria, viruses and ozone production (caused by static electricity) in low RH levels all have an adverse affect on health.
How does the outdoor temperature affect the indoor humidity level?
Allowing cold outdoor air into an indoor environment will lower the indoor humidity. When the lower temperature outdoor air is brought indoors and heated, it loses moisture and reduces the overall RH.
For example: if the outdoor temperature is 0°F and 50% RH and the air comes indoors and is heated to 70°F, the residual moisture after heating the outdoor air will only be about 3% RH. Even on a nice, sunny 35°F and 50% RH day, the residual indoor RH will only be about 14%.