Putting It Into Practice

Controlling the Environment

Typical HVAC Problems

Architectural and building design features (such as windows and vapor barriers) and building operation practices (24-hour systems and the availability of heating and cooling) greatly influence the effectiveness of HVAC systems. Some typical problems with HVAC systems stem from the efforts of facilities personnel to save energy, while others may be due to ignorance or poor maintenance. You should guard against the following:

• Raising the temperature of the chilled water will reduce the ability of the system to dehumidify the air (less water will condense out of the air when it passes over the cooling coil).
• Some systems are not able to dehumidify the air when the outside air is damp, but not warm enough for the air conditioning to go on.
• Turning systems off or setting back the temperature at night and/or on weekends will lead to damaging fluctuations in climate.
• The use of economizer cycles that bring in 100% outside air when outside conditions are moderate may result in higher pollutant levels.
• Humidifiers may be removed or disabled, perhaps due to their need for frequent maintenance. Be aware that disabling a humidifier may be a plus, if it was not working properly in the first place.
• Variable air systems may not deliver a constant volume of treated air to all collection spaces.
• Particulate and gaseous filters that are not changed frequently enough will not function properly.
• System sensors that are not calibrated may lead to undesirable levels of temperature and humidity.
• Keeping doors and windows open will keep the HVAC system from maintaining the desired conditions.

  See a Climate Control Checklist (PDF, 440k).