The large number of faculty, staff and students as well as the number and variety of buildings making up the University community combine to present many unique indoor environmental quality challenges. The types of heating, ventilating and air conditioning (HVAC) systems may vary from building to building. The scheduled HVAC upkeep, ranging from daily cleaning to equipment service is carried out by Physical Facilities staff.

The HVAC system includes all heating, ventilation and cooling equipment serving a building. A properly designed and operating HVAC system will:

  • Control temperature and relative humidity to provide thermal comfort
  • Distribute sufficient amounts of outdoor air to meet the ventilation needs of University operations
  • Isolate and remove odors and contaminants through pressure control, filtration and exhaust fans

Thermal comfort and ventilation needs are met by supplying conditioned air that is a mixture of outdoor and recirculated air that has been filtered, heated or cooled and dehumidified. A number of variables interact to determine whether people are comfortable with the temperature and relative humidity of the indoor air. The amount of clothing, activity level, age, and physiology of people on campus varies widely, so thermal requirements for comfort can vary.


The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 55 describes the temperature and humidity ranges that are comfortable for most people engaged in non-strenuous activities.

Recommended Ranges of Temperature and Relative Humidity

Relative   Humidity

Temperature (Heating)

Temperature (Cooling)


68.5ºF – 75.5ºF  

74.0ºF – 80.0ºF


68.0ºF – 75.0ºF

73.5ºF – 80.0ºF


68.0ºF – 74.5ºF

73.0ºF – 79.0ºF


67.5ºF – 74.0ºF

73.0ºF – 78.5ºF


When indoor temperatures are either above or below recommended comfort zones, people sometimes feel that there is something wrong with the building’s indoor air quality.  However, this is not necessarily the case. Sometimes a simple temperature adjustment can increase occupant comfort.

During cold weather months, there is generally very little moisture in the outdoor air.  As the cold outdoor air is drawn into a building’s ventilation system and subsequently heated, the amount of moisture in the air is reduced further resulting in dry indoor conditions.

Although it is possible to humidify the indoor air in your office through the use of portable humidifiers, Environmental Health and Safety discourages this practice. If indoor moisture levels (relative humidity) rise above a certain level, fungi and bacteria may begin to grow, causing very real indoor air quality problems. Often, humidifiers are not maintained in accordance with manufacturer’s specifications. The water reservoir in these humidifiers may then become an incubator for bacteria and fungi.


Contact EH&S at 7-2211

Last Updated: 3/4/16