Air Conditioning Preventative Checklist

A proper preventative maintenance on your home’s Air Conditioning system will ensure years of comfort and economy. We all know that all equipment eventually needs replaced but with proper service, for minimal cost, done by qualified professionals, that lifespan can be extended. Additionally as utility costs continue to rise your largest appliance needs to be running correctly and efficiently in order to keep your costs minimal.

A proper preventative maintenance visit should include:

Initial Inspection:

  1. Does thermostat work?
  2. Air Handler (indoor unit) operational?
  3. Condenser (outdoor unit) operational?
  4. Air Temperature of home?
  5. Humidity of home?
  6. Are all duct registers and return grills open?
  7. Any warm spots?
  8. Any really cold areas?
  9. Air Filter (clean and size)?
  10. Fan switch operational to ON?

Outdoor Unit:

  1. Clean coil with coil cleaner and inspect for damage
  2. Remove any leaves and debris from around and inside system
  3. Clean and inspect fan blades
  4. Check contacts, relays, and all electrical connections.
  5. Check capacitor for proper wiring and ratings (mfd)/voltage
  6. Verify supply voltage
  7. Check fan motor for wear and shorts (oil if ports are available and not sealed)
  8. Check compressor motor windings (resistance and check for shorts)
  9. Reassemble unit (do air handler/indoor unit maintenance)
  10. Check amperage on outdoor fan and compressor, verify that they meet factory recommendations
  11. Check refrigerant charge using superheat, subcooling, and (for Lennox systems) approach temperatures
  12. After checking indoor temperatures/humidity verify that system is running per manufactures recommendations.

Indoor Unit:

  1. Inspect cooling coil (if cleaning needed, quote customer minimal charge)
  2. Check drain pan
  3. Flush condensate line and verify no leaks
  4. Check drain pan overflow cut-out (this prevents floods if line gets clogged)
  5. Inspect blower motor assembly, clean blower wheel (if cached and removal is needed, quote customer minimal charge)
  6. Check blower motor capacitor
  7. Verify all wiring meets manufacturer specifications
  8. Tighten any wiring terminal connections
  9. Verify transformer amperage draw
  10. Verify supply voltage
  11. Reassemble indoor unit and verify operation
  12. Complete air flow and cooling diagnostics

Air flow and Cooling:

  1. Turn down temperature set-point on thermostat and verify all equipment operational
  2. Allow to run for 5 minutes to stabalize
  3. Check supply duct pressure
  4. Check return duct pressure
  5. Verify total static pressure against indoor unit
  6. Check supply temperature
  7. Check return temperature
  8. Check humidity
  9. Verify temperature split and de-humidification meets manufacturers specifications
  10. Return system to normal operation

Customer Support:

  1. Speak with customer and go over all steps of process
  2. Provide written results and checklist
  3. Provide quote of any additional work that needs to be completed
  4. Provide recommendations for increased efficiency and comfort
  5. Answer any customer questions and address any additional concerns, if minor adjustments make them, if additional work needed provide quote and timeline
  6. Receive payment using approved options (Check, Cash, PayPal).


A good preventative maintenance visit takes a little over an hour to complete and requires specialized tools and chemicals. The technician doing these visits must have knowledge of air conditioning, refrigeration, air flow, and electrical. Preventative maintenance is important for comfort and to extend the lifespan of your equipment.