When fall arrives in Fullerton, the air has a light crispness that signals a welcome break from summer’s heat. As you swap shorts for sweaters and iced drinks for warm ones, your home also begins its seasonal transition. With the cooler weather, your HVAC system shifts from cooling to heating mode, pausing briefly before gearing up to deliver warm air. This seasonal change marks the perfect time to give your system some attention. A bit of care now can maintain HVAC efficiency, improve indoor air quality, and help prevent unexpected breakdowns. Follow this checklist to keep your system performing optimally and ensure your comfort during the mild but cooler days ahead.

Change or Clean Your Air Filters

If there’s one thing to do this fall, it’s to change your HVAC air filter. This small piece of material traps dust, pollen, pet dander, and other debris before they can get into your system. A clean filter allows warm air to flow freely in the cooler months, so your furnace or heat pump won’t have to work as hard. Throughout the fall, check your filters monthly and replace or clean them at least every 60 to 90 days. If you share your home with pets, smokers, or anyone with allergies, a high-efficiency filter can improve indoor air quality while protecting your HVAC components. During high-smog or wildfire seasons, consider changing filters more often. If you’re changing filters but still notice dusty air or weak airflow, you may want to call a technician. They can inspect your ductwork, coils, and blower assembly to make sure there are no bigger issues affecting airflow.

Check and Clean Air Vents and Registers

Uneven heating isn’t always a sign of a major furnace problem; sometimes it’s as simple as blocked or dusty vents. You might have furniture, rugs, or boxes covering registers. When that happens, the system can’t distribute warm air evenly, and your energy bills may climb because it has to work harder. Take this time to walk through your home and look at every vent. Make sure there are no blockages. Give the covers a quick wipe with a damp cloth or vacuum attachment. If you notice visible mold inside vents or a persistent musty odor when the heat kicks on, that’s not a DIY fix. While mold is uncommon in Fullerton’s dry climate, it can occur if there’s excess moisture. In that case, schedule a professional duct cleaning or inspection by a trained technician.

Test Your Thermostat

Thermostats tell your furnace or heat pump when to start and stop. Before the cooler weather settles in, switch your thermostat from “Cool” to “Heat,” or if you have a heat pump, simply change it to heating mode. If you set it a few degrees higher than the current room temperature, the system should respond promptly. If it doesn’t respond, or if the display is blank or flickering, try replacing the batteries. If problems persist, contact a professional. A technician can test the wiring, sensors, and control board. This is also a great time to upgrade to a programmable or smart thermostat. A trained tech can easily make that swap for you.

Clear the Outdoor Unit

While Fullerton doesn’t get snow, outdoor HVAC units still collect leaves, dust, and debris during the fall. Restricted airflow around the condenser or heat pump forces the system to work harder, shortening its lifespan and raising your utility bills. Take a few minutes to clear away leaves, trim plants at least 2 feet back, and gently rinse the outdoor unit with a garden hose. Be sure to shut off power to the system first and use light water pressure; avoid spraying directly into fan openings or electrical components. If you notice unusual noises, bent fins, visible damage, or refrigerant pooling near the unit, stop and call a professional. Attempting repairs on the outdoor component without training can lead to bigger problems.

Watch for Refrigerant Leaks

Refrigerant is the lifeblood of your cooling system and heat pump. While leaks are more noticeable in summer, low refrigerant levels can also reduce a heat pump’s heating performance in cooler months. This can decrease efficiency, drive up bills, and damage the compressor. Homeowners may spot warning signs such as frost on the refrigerant lines, oily residue, or a faint hissing sound near the outdoor unit. If you notice any of these, don’t attempt a DIY fix. Only EPA-certified technicians can handle refrigerant safely and legally in California. Call a certified HVAC professional to test, repair, and recharge the system if you suspect a leak.

Pay Attention to Noises and Odors

Your heating equipment should not rattle, squeal, or emit unusual smells. The first time you turn it on in the fall, a light burning smell is normal as dust burns off, but it should fade within minutes. If the odor persists or you detect a strong burning or gas smell, turn off your system immediately and call your gas company or HVAC technician. Listen for grinding, banging, or squealing noises. Note when and where you hear them, this helps technicians diagnose the issue faster. These are small issues that are easiest and cheapest to fix when caught early.

Schedule a Professional Tune-Up

A fall tune-up gives your HVAC system a full checkup. A certified technician will inspect burners or heating elements, clean coils and other components, check safety controls, and ensure everything runs efficiently. This is especially important if your system is more than a few years old. In Fullerton, homeowners can go months without using their furnace or heat pump’s heating function. That idle time allows dust to collect on burners, coils, and moving parts. Ignoring it can lead to problems when the first chilly night arrives. Scheduling a tune-up now helps catch small issues before they become major repairs. It also improves efficiency, extends equipment life, and may even help maintain your manufacturer’s warranty coverage.

Know When to Call the Experts

Some maintenance tasks make great DIY projects, but electrical inspections, refrigerant handling, or internal component repairs require specialized training. If your system keeps cycling, won’t turn on, or blows cool air when it should be heating, it’s time to call a professional. Your HVAC system is one of the hardest-working appliances in your home. It deserves a little attention as the seasons change. You can handle simple upkeep like changing filters, checking thermostats, and clearing debris, but always leave complex repairs to trained technicians. With the right maintenance and support, you’ll enjoy reliable, efficient comfort all season long.

Call for Professional Help Today

One Hour Heating & Air Conditioning® offers a 100% satisfaction guarantee and emergency HVAC services, so you’re never left out in the cold or the heat. Whether you need a detailed HVAC inspection, routine maintenance to keep your furnace or heat pump running smoothly, or a brand-new installation, our team is ready to help. Call One Hour Heating & Air Conditioning® today to schedule your HVAC service in Fullerton and stay comfortable in every season.