View Entire PIM

checkReplace air-handling unit (AHU) filters regularly.

All PIM content was independently developed and reviewed to be vendor-, product-, and service provider-neutral.


Check and replace air-handling unit (AHU) filters regularly to ensure proper function and maximize system operation. Keeping filters and coils clean can dramatically improve the efficiency of the entire HVAC system.

  • Project Talking Points

    • Overloaded filters can increase the energy demand on fans.
    • Overloaded filters can reduce the volume of supply air, resulting in mproper system operation.
    • Continually assessing new filter technologies facilitates adoption of filters with improved efficiency and durability.
    • Increasing the filter cross-sectional area (angled filter bags, pleated filters) provides more energy-efficient filtration. 
  • Triple Bottom Line Benefits

    • Cost benefits: Energy savings result in cost savings. Regular filter replacement prevents pollutant overloading and improves energy performance. See case studies for specific examples.
    • Environmental benefits: Reducing energy use always has an environmental benefit (see the Roadmap Benefits Calculator page). In addition, filter replacement can result in more efficient filter function and improved air quality.
    • Health and safety benefits: Regular filter replacement should improve indoor air quality, enhancing patient and staff experience.

    Quality and outcomes: Metrics are in development.  If you have suggestions, please contact us or participate in the discussion below.

  • 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. Consult the infection prevention and safety officer regarding potential temporary shutdowns during filter changes in ventilation systems serving patient care areas.
    3. Perform a walk-through to inspect AHUs throughout the facility and document the results:
      • Develop an AHU log with the following information:
        • All AHU equipment locations by space designation, zone, location, and floor area serviced
        • For each AHU: the required filter size, quantity of filters, MERV rating of the current filter, and  manufacturer’s recommended differential pressure for change out
        • Which filters have differential pressure gauges and which are monitored by the BAS
      • Check for damage and/or moisture on existing filters and filter fasteners.
        • Damaged filters should be changed immediately to reduce the risk of microbial growth and (in the case of tears or punctures) dirt being introduced into the ductwork.
        • Maintenance personnel should identify and correct the source of moisture, whether a leak or condensation from HVAC equipment.
      • Check filter mounting racks and seals for proper sealing/mating. Check for evidence of leakage around the sealing surfaces.
    4. Verify that current filters meet ventilation requirements and are optimized to the existing HVAC system:
      • Review filtration requirements per space designation as outlined in Table 6.1 (Minimum Filter Efficiencies) in ANSI/ASHRAE/ASHE 170: Ventilation of Health Care Facilities (also pubished as part of the Guidelines for Design and Construction of Health Care Facilities).
      • If filters do not meet current MERV minimums, consider changing to filters with updated MERV ratings.
    5. When filters are to be replaced, notify occupants that the AHUs will be shut down for approximately 15 minutes duriing replacement. If possible, perform the replacement during off-hours to minimize disruption in operations.
    6. Shut down equipment prior to replacing the filters.
    7. When placing the filters in the filter rack, ensure the airflow arrow is pointing away from the cooling coil and the filter media is sealed in the frame to keep bypass air from entering the duct.
    8. Seal cracks between filter frames and between the filter bank and the duct wall.
    9. Consult with the building engineer or an outside engineering consultant regarding performing air balancing to maximize energy efficiency.
    10. Schedule regular filter replacements as recommended by the manufacturer. Replace filters more often under extreme conditions.
    11. If one is not already in place, consider installing a differential pressure measurement device across the filter bank to monitor pressure drops via the facility’s building automation system (BAS).
      • Monitoring the pressure drop across filter banks and adjusting replacement schedules according to actual conditions instead of using “time-based” replacement schedules can reduce maintenance labor and filter material expenses.
    12. Log all filter replacement activities in the AHU log.
    13. Coordinate with performance improvement measures Retrocommission HVAC controls and 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.

  • Regulations, Codes and Standards, Policies

  • 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
      • Indoor Environmental Quality Credit 1.4: IAQ Best Management Practices-Reduce Particulates in Air Distribution
    • 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
      • Indoor Environmental Quality Credit 5: Indoor Chemical and Pollutant Source Control 
  • 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

  • Education Resources

    If you have any information or resources to contribute, please contact us or participate in the discussion below.

  • More Resources

  • PIM Descriptors


    Level: Beginner

    Category List:

    • Building and Maintenance
    • Commissioning
    • HVAC

    PIM Attributes:

    • Environmental Health and Safety
    • 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
  • This resource was underwritten by  Camfil Clean Air Solutions


  1. Comment, and please add information, tools, or additional resources you think should be added to the PIM.
  2. Write a case study or a PIM to contribute to the Roadmap (links are to instructions).

Home About Topics Drivers Strategies Implementation Resources Terms of Use Privacy Policy
American Hospital Association | 155 N. Wacker Drive, Suite 400 | Chicago, Illinois 60606 | (312) 422-3000
©2010-2015 by the American Hospital Association. All rights reserved.