Summary

• Proper heating and cooling system design, equipment selection, and optimization can lead to conditioned spaces that are more comfortable, more productive, and save money, energy, and the environment.
  
  
• Choose high-efficiency equipment that matches loads.
  
  
• Reduce fan energy, if possible, since fans typically represent between 20 to 30 percent of total HVAC energy usage and often present a significant opportunity for energy savings. Two-speed fans, adjustable speed drives, and variable air volume systems can considerably reduce fan energy.
  
  
• Take advantage of natural cooling where available. Free cooling can be achieved by the use of economizers that take advantage of outdoor air to meet cooling loads. Specify integrated air economizers for most systems greater than 7.5 tons. Where appropriate, use temperature and enthalpy controls.
  
  
• Reduce reheat energy in mild climates by using an air-side economizer and by capturing heat that would normally be wasted, particularly in areas like commercial laundries where heat recovery for water heating is often cost-effective due to the significant quantities of waste heat generated.
  
  
• For central systems, where feasible, specify modulating equipment or multiple small boilers or chillers with staged operation.
  
  
• Commission new building systems to make sure the system is performing as it should. This process includes starting, testing, and balancing all equipment. ASHRAE publishes guidelines for building commissioning (ASHRAE. 1996. Guideline 1-1996-The HVAC Commissioning Process. Atlanta, Ga.: ASHRAE).
  
  
• Establish operation and maintenance protocols and conduct routine maintenance of all building systems. These protocols should include regular filter changes; verifying that fan belts, compressors, and dampers are operational; cleaning of cooling and condenser coils, fans, drains, and flues; calibrating controls; checking and adjusting fluid levels (i.e., refrigerant or lubricants); and adjusting the fuel/air mixture of any gas- or oil-burning equipment. If you do not have full-time staff available for maintenance, it is wise to retain a qualified maintenance service organization.
  
  
• Monitor system performance to better understand the "typical" operating profile of the building and to identify any system and component failures. Recommission building systems periodically to ensure continued successful, efficient performance.