Seasonal HVAC Maintenance Checklist
Published on January 4, 2026 • 8 min read
Keeping your heating, ventilation, and air‑conditioning (HVAC) system in peak condition year‑round is essential for comfort, energy savings, and indoor air quality. A systematic, season‑by‑season maintenance routine helps you catch problems early, avoid costly breakdowns, and extend the lifespan of expensive equipment.
Why a Seasonal Checklist Matters
- Energy Efficiency: A clean, well‑tuned system can reduce energy usage by 10‑15%.
- Equipment Longevity: Regular care adds 3‑5 years to furnace and AC life.
- Health & Comfort: Proper airflow and filtration lower allergens, mold, and humidity‑related issues.
Winter (Heating Season) – October – February
- Inspect & Replace Furnace Filters: Use a MERV 13 filter; replace every 30‑60 days.
- Check Thermostat Calibration: Verify temperature accuracy; consider a programmable or smart thermostat for better control.
- Examine Heat Exchanger for Cracks: Look for soot or discoloration; a cracked heat exchanger can leak carbon monoxide.
- Test Safety Controls: Verify the operation of the high‑limit switch and flame sensor.
- Clean Blower Assembly: Remove dust from the blower wheel and motor housing.
- Inspect Ductwork for Leaks: Seal gaps with mastic or foil‑backed tape; unsealed ducts can lose up to 30% of heated air.
- Check Condensate Drain (if humidifier present): Ensure it’s clear to prevent water damage.
- Schedule Professional Furnace Tune‑Up: A certified technician will perform a combustion analysis, check gas pressure, and clean the burners.
Spring (Transition) – March – May
- Replace Filters Again: Spring pollen spikes demand fresh filters.
- Run the System in “Fan‑Only” Mode: Circulate air to dry any residual moisture in ducts.
- Inspect and Clean AC Evaporator Coil: A dirty coil reduces cooling efficiency; use a no‑rinse coil cleaner.
- Check Refrigerant Levels: Low refrigerant can indicate leaks; a professional should handle recharging.
- Test Drain Pan & Condensate Line: Ensure water is draining properly; clear any clogs.
- Schedule Duct Cleaning (if not done in summer): Remove dust, pollen, and any residual mold spores.
Summer (Cooling Season) – June – September
- Replace Filters with a High‑Efficiency (MERV 13) Model: Replace every 30 days under heavy use.
- Clean Outdoor Condenser Unit: Remove leaves, debris, and vacuum fins; ensure at least 2 inches of clearance around the unit.
- Inspect Fan Motor & Capacitor: Listen for humming or rattling; replace worn capacitors.
- Check Refrigerant Pressures: Verify both high‑side and low‑side pressures match manufacturer specs.
- Run a System Efficiency Test: Use a BTU calculator or have a technician perform a SEER verification.
- Inspect Duct Insulation: Ensure any exposed ducts in unconditioned spaces are insulated (R‑value ≥ 8).
- Schedule Professional AC Tune‑Up: Includes coil cleaning, refrigerant check, and blower inspection.
Fall (Transition) – October – November
- Replace Filters One Last Time Before Winter: Use a high‑MERV filter to capture autumn leaves and spores.
- Turn Off or Cover Outdoor Condenser: Protect it from falling leaves and early frost.
- Inspect Heat Pump Reversal Valve (if applicable): Ensure it switches correctly between heating and cooling modes.
- Check Thermostat Batteries or Power Source: Replace batteries or verify Wi‑Fi connectivity.
- Schedule a Full System Inspection: A comprehensive check before the heating season begins.
Year‑Round Tasks
- Monitor Indoor Humidity: Keep RH between 30%‑50% using humidifiers or dehumidifiers as needed.
- Test Carbon Monoxide Detectors: Replace batteries annually; ensure they’re within 10 ft of the furnace.
- Inspect and Clean Return Grilles: Remove dust and debris to maintain airflow.
- Run a Quick Energy Audit: Use a smart plug or utility‑provided tool to identify spikes in usage.
Quick Reference Table
| Season | Key Tasks |
|---|---|
| Winter (Oct‑Feb) | Filter change, heat‑exchanger check, blower cleaning, professional furnace tune‑up. |
| Spring (Mar‑May) | Filter change, fan‑only run, evaporator coil cleaning, refrigerant check, duct cleaning. |
| Summer (Jun‑Sep) | Filter change, condenser cleaning, refrigerant pressure check, SEER verification, AC tune‑up. |
| Fall (Oct‑Nov) | Final filter change, condenser cover, heat‑pump valve check, full system inspection. |
Cost vs. Savings Snapshot
Investing in a professional tune‑up typically costs $150‑$250 per season. The average homeowner recoups 60‑80% of that cost through reduced energy bills and avoided emergency repairs.
Bottom Line
Following this seasonal checklist empowers you to keep your HVAC system running efficiently, safely, and quietly all year long. Small, regular actions prevent big, costly failures and ensure the indoor air you breathe is clean and comfortable.