HVAC systems serving commercial buildings contain many working parts and are a costly, yet necessary, investment. Routine maintenance of existing HVAC systems is necessary to keep them working optimally for the longest time possible. However, each system has a limited life expectancy. Replacement or retrofitting can provide an opportunity to utilize more energy efficient equipment that will reduce operating costs over the life of the system. Consideration for high efficiency systems and advanced control strategies when laying out a HVAC system for a new building can also positively impact operating costs. Sometimes even paying back the cost to implement them.




Maintenance of an existing facility is improved by developing and following a Preventive Maintenance Plan (PMP). Equipment and equipment that are good candidates for inclusion in your PMP will have the following characteristics:

  • The repair/replacement costs are high
  • Maintenance must be performed routinely
  •  The equipment is critical to occupant comfort and your company’s success.

The following equipment information is useful to include in your PMP:

  • Make and model of the equipment
  • Serial number
  • Basic specification and capabilities
  • Asset number, brass tag number, or unit number
  • Category (HVAC, plumbing, electrical, etc)
  • The location of the equipment
  • The department who holds responsibility
  • Any high cost or long lead time items of the asset

Additional maintenance requirements can be found in the manufacturer’s operations and maintenance manuals provided with the equipment. Once all the information has been gathered, a list of maintenance actions and frequency can be established and assigned to personnel. It is important to anticipate equipment operating life so budgeting for a replacement can occur at the proper time.

Tables are available from ASHRAE with median service life listed for various equipment types at



Retrofitting equipment and controls can be beneficial when looking to reduce energy use in an existing facility. A good starting point is to set a baseline for your building’s energy performance. We recommend using the Energy Star Portfolio Manager®. This is a free tool used to compare your building energy use with similar buildings throughout the country. Some Building Controls retrofit strategies include:

Supply Air Temperature Reset
• Reduces amount of reheat energy required

Supply Water Temperature Reset
• Lower return water temperature entering boiler increases equipment efficiency

Programmable Thermostats/Occupancy Sensors
• Setback/Setup temperatures in spaces when unoccupied for energy savings

Lastly, replace existing inefficient equipment with new, high efficiency




New Construction

New Construction allows for the incorporation of high efficiency equipment. Some basic information is as follows:

High Efficiency Equipment
• While there is a premium price for higher efficiency equipment, paybacks are usually less than 5 years.
• In some cases utility rebate programs also help reduce costs.

Energy Recovery
• Can reduce outside air heating/cooling up to 75%.
• Prohibited from use in some applications (labs, kitchens).

• Payback varies greatly depending on local soil conditions, application and comparison system.
• Will usually require in depth analysis to determine if viable; don’t always trust simple paybacks.
• Request Geotech report. Test bores recommended.


For more information on Effective Facility Maintenance and Energy Management of HVAC Systems in Commercial Applications or other HVAC topics, please contact:


Christopher Staab, PE, LEED AP BD+C
Vice President
Director of Mechanical Engineering
direct 414.918.1223