If you live in the San Gabriel Valley, you know fall weather doesn’t always behave. One day it’s sunny and 90° in Pasadena, and the next morning you’re reaching for a sweater in Glendora. These quick shifts can make it hard to know when to switch your thermostat from cooling to heating — but doing it the right way matters more than you might think.
Switching from AC to heat isn’t just flipping a switch. It’s about prepping your HVAC system to handle steady use after sitting idle for months. Taking a few smart steps now can prevent costly repairs later — and keep your home comfortable all season long.
When Should San Gabriel Valley Homeowners Flip to Heat?
There’s no official “heating season” in Southern California, but a good rule of thumb is to switch when your indoor temps drop below 68°F during the day and nights dip into the 50s — especially in foothill areas like Azusa, Monrovia, or La Verne.
Don’t wait until you’re cold to turn on the heat. Early to mid-fall is the perfect time to test your system. Once the first real chill hits, HVAC appointments fill up fast across the San Gabriel Valley.
Call Cypress Heating & Air Conditioning at (626) 963-9810 to schedule your fall tune-up before the rush.
Quick Safety Check Before Turning on the Heat
Before you flip that thermostat, take a few minutes to go through this quick checklist:
- Test Your Thermostat
Switch to “Heat” and listen for the system to kick on. If nothing happens, check your thermostat batteries or wiring. Consider upgrading to a smart thermostat for better comfort and energy savings. - Smell for Trouble
A slight burning-dust smell is normal at first, but if you notice gas, rotten eggs, or metal-like odors, turn everything off and call for service immediately. - Listen for Noises
Rattles, bangs, or squeals can point to worn belts, loose parts, or a cracked heat exchanger. Don’t ignore them — call Cypress for an inspection. - Check for Blockages
Clear leaves, dust, or debris around your outdoor unit and replace your air filter if it’s dirty. Good airflow means better performance and cleaner indoor air.
Prevent Short Cycling with Smart Thermostat Settings
One of the most common fall issues in SGV is short cycling — when your system keeps turning on and off before completing a full cycle. It wastes energy and wears out parts faster.
Keep your thermostat between 68°F–72°F, and avoid frequent manual changes. Use your thermostat’s “hold” or “auto” settings to keep it consistent. If short cycling continues, it could mean a blocked duct, low refrigerant, or sensor problem. Our technicians can diagnose it during your tune-up.
Replace Filters and Check Airflow
It’s simple but important — replace your air filter every 1–3 months. A clogged filter makes your system work harder and can raise your energy bills.
Then, walk through your home and make sure every vent is open and clear. Move furniture, curtains, or rugs that block airflow, and peek inside vents for dust buildup.
Special Tips for Heat Pump Owners
If you have a heat pump — common in newer homes or remodeled properties — follow these steps before switching to heat:
- Clear Outdoor Debris
Remove leaves, branches, and clutter from around your outdoor unit. - Check for Ice or Water
If you notice ice buildup or pooling water, turn it off and call for service. - Test the Reversing Valve
If it won’t switch from cool to heat, this valve may be stuck — it’s a professional fix. - Flush the Drain Line
A quick flush prevents leaks or mold growth - Book Preventive Maintenance
Cypress technicians can check refrigerant levels, clean coils, and verify performance before the heating season starts.
Seal Duct Leaks and Stop Energy Loss
Even mild winters in the Valley can reveal ductwork problems. Cracks or gaps in ducts — especially in attics and garages — can waste up to 30% of your heated air.
If you notice rooms that heat unevenly or feel extra dusty, you may need duct sealing or insulation. Cypress offers full duct inspections to pinpoint and fix leaks before they raise your bills.
Balance Indoor Air Quality and Humidity
As the dry Santa Ana winds roll through, indoor humidity drops. Combine that with heating, and you can end up with dry skin, static shocks, and scratchy throats.
Installing a whole-home humidifier helps maintain ideal humidity levels, keeps your wood furniture and flooring from cracking, and makes your home feel warmer without raising the thermostat.
Stay Ahead of Weather Swings
From Altadena to Covina, fall can bring triple-digit highs one week and chilly nights the next. Those temperature swings can strain your HVAC system, especially if it hasn’t been serviced recently.
Set your thermostat to “Auto” mode so it can switch between heating and cooling automatically. If your energy bills spike or you notice inconsistent performance, it’s time for a check-up.
Schedule Your Fall Tune-Up with Cypress Heating & Air Conditioning
Now’s the perfect time to prepare your home for the cooler months ahead. Our licensed HVAC technicians at Cypress Heating & Air Conditioning will inspect your furnace or heat pump, clean components, check safety systems, and ensure your equipment runs efficiently and safely.
We’ve proudly served the San Gabriel Valley since 1967 — from Pasadena to Glendora and beyond. Call (626) 963-9810 or schedule a service visit online.
