In Southern California, your air conditioner works hard all summer and then your heater sits idle for months — until the first chilly evening when you flip it on and hope for the best. October is the ideal time for a fall HVAC tune-up: the cooling season is winding down, heating season has not started, and a little maintenance now prevents the no-heat call nobody wants in December. Here is the checklist our technicians run through every fall.

Change the Filter and Check Airflow

Start with the simplest, most skipped step: the air filter. A clogged filter chokes airflow, which makes the system work harder in both heating and cooling modes and can cause the furnace to overheat and shut down on a safety limit. If you have been running the AC all summer, that filter is spent. Replace it now, and check it monthly through the winter — heating season moves a lot of air too.

Clear and Inspect the Outdoor Unit

Summer leaves its mark on the condenser: leaves, dirt, cottonwood fluff, and the occasional forgotten garden tool. Clear debris from around the unit and gently rinse the fins. While you are out there, look for anything visibly wrong — bent fins, damaged insulation on the refrigerant lines, or vegetation growing into the unit. Two feet of clear space on all sides is the rule of thumb.

Test the Heat Before You Actually Need It

Do not wait for the first cold snap to find out your heater has a problem. Pick a mild October day, set the thermostat to heat, and let the system run for 15 to 20 minutes. Listen for anything unusual — banging, squealing, or a burner that cycles on and off rapidly. Check that warm air is coming from the vents in every room. A faint dusty smell on first startup is normal; a strong burning smell or any smell of gas is not, and means you should shut the system off and call a professional.

Check the Thermostat and Carbon Monoxide Detectors

Fall is the time to make sure the thermostat is reading accurately and switching between modes cleanly. If you have an older manual thermostat, this is a good moment to consider a programmable or smart model — Southern California's big day-night temperature swings make setback schedules genuinely useful. And if your home has any gas-burning appliances, test the carbon monoxide detectors and replace batteries. Heating season is carbon monoxide season.

Look at the Ductwork

Ducts lose efficiency silently. Walk through the attic or crawlspace if you can access it safely and look for disconnected sections, crushed flex duct, or insulation that has slipped off. Rooms that never quite reach temperature are often a duct problem, not an equipment problem. Sealing and insulating ducts is one of the highest-return improvements a homeowner can make.

Do Not Forget the Electrical Side

Your HVAC system is one of the biggest electrical loads in the house. A fall tune-up is a good time to check that breakers are not running hot, the disconnect is in good shape, and the wiring to the unit is intact. Because we handle both HVAC and electrical, our technicians check the whole picture — the equipment and the power feeding it.

Schedule the Professional Tune-Up

The homeowner checklist covers the basics, but a professional tune-up goes deeper: measuring refrigerant charge, testing capacitors and contactors, cleaning the blower assembly, checking heat exchanger integrity, and verifying safe combustion on gas furnaces. An hour of maintenance in October is cheap insurance against a dead system on a cold night.

Get ahead of heating season now. Call Mars HVAC & Electric at 310.880.9718 to schedule your fall tune-up — we serve West Hollywood and the greater Los Angeles area from our shop at 8605 Santa Monica Blvd.