Fall HVAC Maintenance Checklist for San Antonio Homeowners

San Antonio winters are mild, but that first real cold front always seems to catch people off guard — and a furnace that hasn't run since March is exactly when small problems turn into no-heat calls. Run through this checklist in September or October, before you actually need the heat.

1. Schedule a Professional Furnace Tune-Up

A tune-up catches worn igniters, dirty flame sensors, and cracked heat exchangers while they're a scheduled visit instead of an emergency call. It's the single most effective thing on this list.

2. Replace or Check Your Air Filter

Filters clogged from a summer of AC use restrict airflow for your furnace too. Swap it now — see our guide on how often to change your filter in Texas conditions.

3. Test Your Heating System Before You Need It

Run your heat for 10-15 minutes on a warm day. It's far easier to fix a no-heat issue in 75-degree weather than at 6am on the year's first cold morning.

4. Check Your Thermostat Batteries & Settings

Dead batteries are a surprisingly common reason a furnace "won't turn on." If you have a programmable or smart thermostat, this is also a good time to set your winter schedule.

5. Inspect and Clean the Outdoor Unit

Clear leaves, grass clippings, and debris from around your outdoor unit. A summer's worth of buildup can restrict airflow well into fall.

6. Test Your Carbon Monoxide Detectors

If you have a gas furnace, working CO detectors are non-negotiable. Test them now, and replace batteries if needed — this is especially important the first time you fire up a furnace after months of sitting idle.

7. Check for Duct Leaks

Leaky ductwork wastes heated air before it reaches your rooms, especially in attic runs exposed to months of Texas heat. If certain rooms never seem to warm up, this is often why.

8. Clear Vents and Registers

Furniture, rugs, and curtains that shifted over summer can block vents without you noticing. Walk the house and make sure every register has a clear path.

9. Consider a Year-Round Maintenance Plan

A maintenance plan covers both your spring AC check and fall furnace tune-up, so you're never troubleshooting a system that hasn't been looked at in a year.