Learning Center
HVAC Maintenance Checklist
What homeowners can do themselves — organized by season — plus a complete list of what professional tune-up service covers.
What You Can Do
Homeowner Maintenance — Seasonal Checklist
No special tools or certifications required. These tasks take 5–30 minutes total and make a meaningful difference in system performance and lifespan.
Monthly (Peak Season — May through September)
Check and replace air filter
1-inch filters should be checked monthly during peak season. During NC pollen season (March–May), check every 2–3 weeks. Replace before it becomes visibly clogged — don't wait until it's packed solid.
Verify all supply and return vents are fully open
Closing vents in unused rooms is a common mistake — it increases system pressure and can cause coil icing and blower strain. All vents should remain open.
Check outdoor unit clearance
Keep grass, weeds, and shrubs trimmed to at least 18 inches from all sides of the outdoor unit. Remove any leaves or debris from the top of the unit.
Listen for new sounds
Any new rattling, grinding, clicking, squealing, or banging that wasn't present previously is worth noting and mentioning at your next service call — or calling sooner if it intensifies.
Spring (March–April) — Before Cooling Season
Replace air filter
Start the cooling season fresh, even if you recently replaced it.
Treat condensate drain line
Pour 1 cup of diluted bleach (1 part bleach, 1 part water) slowly into the condensate drain access port. This kills algae before it has a chance to clog the line.
Rinse outdoor condenser coil
Use a garden hose on a gentle setting to rinse pollen and debris from the condenser coil fins. Rinse from the inside out if possible, or gently from the outside. Never use a pressure washer — it bends fins permanently.
Test the system before it's hot
Switch to COOL mode and run the system for 10–15 minutes on a mild spring day. Verify cool air from vents and check that the outdoor unit is running. Much easier to address problems in April than in July.
Schedule professional tune-up
The best time for AC tune-up is April–early May, before peak season demand. In peak summer, scheduling a tune-up may take longer.
Fall (September–October) — Before Heating Season
Replace air filter
Start the heating season with a fresh filter.
Test heating mode
Switch the thermostat to HEAT and run for 10–15 minutes on a cool day. Verify warm air from vents before the first cold snap arrives.
Clear debris from outdoor unit
Falling leaves and seeds can accumulate around and inside the outdoor unit. Remove any visible debris.
Check thermostat batteries
If the thermostat uses batteries, fall is a good time to replace them before cold weather demands peak.
Schedule heating tune-up
Heat pump or furnace inspection in September or October catches problems before the heating season's first cold emergency.
Winter (December–February)
Monitor outdoor unit for excessive ice
Heat pumps form light ice on the outdoor coil during winter — this is normal and cleared by the defrost cycle. Thick ice that doesn't clear in 1–2 hours is not normal — call for service.
Confirm AUX HEAT operation
If the thermostat shows AUX HEAT continuously, even above 40°F outdoor temperature, the heat pump may not be generating enough heat. This warrants a service call before a cold snap arrives.
Keep return vents unobstructed
Winter furniture rearrangements often inadvertently block return vents. Check that nothing has been placed against or over return grilles.
Professional Service
What a Professional Tune-Up Covers
These tasks require specialized instruments, refrigerant certification, and HVAC training. They're performed during an annual tune-up visit and documented for warranty records.
Refrigerant pressure check and charge verification
Ensures the system is operating at designed refrigerant levels — critical for efficiency and compressor protection.
Capacitor testing (start and run capacitors)
Capacitor strength measured with a meter. Weakening capacitors identified before they fail and damage motors or the compressor.
Evaporator coil inspection and cleaning
The indoor coil accumulates dust, pollen, and mold spores over time. Professional cleaning with approved coil cleaner restores heat-transfer efficiency.
Condenser coil cleaning
The outdoor coil receives professional cleaning — fins straightened if needed, chemical coil cleaner applied and rinsed.
Condensate drain flush and treatment
Full drain line flush and algae treatment to prevent mid-season clogs and overflow.
Electrical connection inspection and tightening
All terminal connections checked for corrosion, looseness, or arcing damage. Tightened to spec.
Contactor inspection
The contactor switches high voltage to the compressor and condenser fan. Pitted or burned contacts indicate imminent failure.
Blower motor amperage and condition check
Motor amperage measured and compared to nameplate rating. Dirty blower wheel cleaned if accessible.
Thermostat calibration and operation test
Thermostat accuracy verified and cycling tested.
Airflow measurement at supply vents
Identifies duct leaks, restrictions, or imbalanced airflow across zones.
Heat exchanger inspection (gas furnace/dual-fuel)
Visual inspection for cracks that could allow combustion gases to mix with indoor air — a safety-critical check.
Defrost cycle test (heat pumps)
Defrost cycle functionality verified before winter heating season.
System performance report
Dated documentation of all measurements, findings, and any recommended work — valuable for warranty documentation.
Schedule Your Annual Tune-Up
Junior Collins HVAC performs the complete professional checklist above on every maintenance visit, with dated documentation. NC License #27258 · Serving the NC Foothills since 2003.