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checkPerform economizer maintenance.

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Improve energy efficiency and reduce the risk of compromised indoor air quality by regularly inspecting economizer operation and repairing linkages that may be broken or stuck, reducing system performance.

  • Project Talking Points

    • Enhances energy efficiency, reduces costs, and extends the life of equipment by maintaining the equipment so it operates as designed. Maintenance of economizers is particularly important because if they fail with the outside air damper open energy consumption could sharply increase.
    • System reliability is improved by scheduling maintenance activities proactively, rather than in response to a disruption in service. 
  • Triple Bottom Line Benefits

    • Cost benefits: Energy savings and increased equipment life result in cost savings.  Economizer maintenance is less expensive than early replacement of equipment and often results in energy savings. See case studies for specific examples. 
    • Environmental benefits: Reducing energy use reduces emissions and environmental impact (see Benefits Calculator Page).  Extending the life of equipment also has both cost and environmental benefits that are harder to quantify but can be duly noted.
    • Social benefits: Depending upon the improvements made to equipment, controllability and thermal comfort may be improved which enhances patient and staff experience.
    • Quality and outcomes - Metrics are in development. If you have suggestions, please contact us or participate in the discussion below.
  • Commissioning Connections

    The ASHE Health Facility Commissioning Guidelines and accompanying Health Facility Commissioning Handbook are good information sources for undertaking this performance improvement measure.

    • 6.1 The Retrocommissioning Process (in both books)

    (24) Develop revised air-handling unit sequences of operation and set points for optimum energy efficiency (supply air temperature control, humidity control, economizer cycles, damper sequencing, supply air temperature set-point reset, and supply air static pressure set point reset).

  • Purchasing Considerations

    If you have suggestions for purchasing considerations, or suggested sample contract language for any product or contracted service, please participate in the discussion below.

  • How-To

    1. Determine who's on the team: commissioning agent, building engineer, HVAC maintenance personnel, BAS manager.
    2. Review historic data from the building automation system (BAS) to identify economizers that may not be working properly. For example, a supply- and exhaust-air imbalance may signal that an outdoor air damper is stuck in the open position.
    3. At least twice a year, perform a facility walkthrough to inspect and repair economizer equipment.
    4. A good way to check the performance of damper operation and calibration is to take CO2 or dry-bulb temperature readings at various damper settings (including outside air damper closed position) and use the following formula to correlate actual outside airflows:

      % OA = (Xr-Xs)/(Xo-Xs) X 100%


      Xr= return air CO2 or dry-bulb temperature

      Xs= supply air CO2 or dry-bulb temperature

      Xo= outside air CO2 or dry-bulb temperature

    5. At minimum, check the following:
      • Corrosion and deposits of dirt and moisture that could cause the outside air damper and/or linkages to freeze in place
      • Actuator or linkage loose connections
      • Temperature or enthalpy sensor
      • Operating mixed air temperature to see if it is too high or too low
      • Control settings for high-limit temperature, lockout temperature, and building pressure
      • Economizer damper blade seals to inspect for proper sealing when the economizer is in fully closed 
    6. Clean and lubricate the outside air damper. Replace if a damper is corroded beyond repair.
      • Clean linkages and verify they are properly connected to the damper.
      • Verify the actuator is connected to a power supply and functioning properly.
      • Calibrate the enthalpy sensor, and check that it is functioning properly. (An enthalpy sensor helps control the amount of moisture in the air and helps determine when sensible heat can be recovered.)
      • Program the BAS to “exercise/cycle” the economizer regularly by opening and closing the dampers to reduce the risk of freezing up in between maintenance inspections.
      • Continue to track economizer performance using BAS trending data.
      • Integrate the economizer maintenance program into performance improvement measure Retrocommission HVAC controls and performance improvement measure Practice preventive maintenance of major HVAC equipment.
  • Tools

    If you have an ROI tool, calculator, or similar resources to share, please contact us or participate in the discussion below.

  • Case Studies

    Advocate Good Samaritan Hospital (Downers Grove, Ill.)

    • Key Points
      • Hospital received a $50,400 incentive for a project costing $82,999. Less than 17-month payback period.
      • Majority of repairs were related to the economizer: dampers, humidity sensors, setpoint.

    Pacific Gas & Electric Retrocommissioning Program for Hospitals

    • Key Point
      • Comparison of ROI for economizer repair projects on three hospitals ranging from 8.4- to 14.4-month simple payback periods.
  • Regulations, Codes and Standards, Policies

    American Society of Heating, Refrigerating and Air-Conditioning Engineers (

  • Cross References: LEED

    • LEED for Existing Buildings: Operations + Maintenance
      • Energy & Atmosphere Prerequisite 1: Energy Efficiency Best Management Practices—Planning, Documentation, & Opportunity Assessment
      • Energy & Atmosphere Prerequisite 2: Minimum Energy Performance
      • Energy & Atmosphere Credit 1: Optimize Energy Efficiency Performance
      • Energy & Atmosphere Credit 2.1: Existing Building Commissioning—Investigation & Analysis
      • Energy & Atmosphere Credit 2.1: Existing Building Commissioning—Implementation
      • Energy & Atmosphere Credit 3.1: Performance Measurement—Building Automation System
      • Energy & Atmosphere Credit 5: Measurement & Verification
    • LEED for Healthcare: New Construction and Major Renovations
      • Energy & Atmosphere Prerequisite 1: Fundamental Commissioning of Building Energy Systems
      • Energy & Atmosphere Prerequisite 2: Minimum Energy Efficiency Performance
      • Energy & Atmosphere Credit 1: Optimize Energy Efficiency Performance
      • Energy & Atmosphere Credit 3: Enhanced Commissioning
      • Energy & Atmosphere Credit 5: Measurement and Verification
  • Cross References: GGHC

    • Green Guide for Health Care: Operations Section
      • Facilities Management Prerequisite 1: Energy Efficiency Best Management Practices—Planning, Documentation, & Opportunity Assessment
      • Facilities Management Prerequisite 2: Minimum Energy Efficiency Performance
      • Facilities Management Credit 1: Optimize Energy Efficiency Performance
      • Facilities Management Credit 3.1: Existing Building Commissioning—Investigation & Analysis
      • Facilities Management Credit 3.2: Existing Building Commissioning—Implementation
      • Facilities Management Credit 3.3: Existing Building Commissioning—Ongoing Commissioning
      • Facilities Management Credit 4.3: Building Operations & Maintenance: Building Systems Monitoring
  • PIM Synergies

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  • PIM Descriptors


    Level: Beginner

    Category List:

    • Building and Maintenance
    • Commissioning
    • Contracted Services
    • HVAC

    PIM Attributes:

    • Optimize Operations
    • Repair or Optimize Existing Systems (fix what you have)

    Improvement Type:

    • Commission/Retro-Commission
    • Retrofit/Renovations
    • New Buildings
    • Operations and Maintenance


    • Engineering/Facilities Management
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