Why Your Heater Runs Constantly in Winter in Southern California

If your heater seems to run all the time during winter, the cause is often simple and fixable. In Southern California, this issue is more common than many homeowners expect.

Temperature Swings Are the Main Reason

Winter in Southern California is very different from colder climates. Nights can feel chilly, while afternoons may warm up quickly, especially when the sun hits windows and exterior walls. These daily temperature swings make your heating system work harder to maintain a stable indoor temperature.

When temperatures drop quickly after sunset, your heater may run longer cycles just to restore comfort. This doesn’t always mean something is broken sometimes the system is simply responding to changing outdoor conditions.

However, if your heater seems to run continuously even when the weather is mild, it’s worth checking a few common factors that may be reducing efficiency.

Airflow Restrictions Can Make Heating Slower

A clogged air filter is one of the most common reasons a heater runs longer than expected. When airflow is restricted, warm air cannot circulate efficiently, and the system needs more time to reach the desired temperature.

Blocked vents, closed registers, or furniture placed in front of vents can have a similar effect. Even small obstructions can reduce airflow enough to impact performance and comfort in different rooms.

Many homeowners don’t realize how quickly filters can become dirty, especially if the system was heavily used during the summer cooling season. Replacing the filter regularly is one of the simplest ways to improve heating performance.

If airflow has been an issue in your home, this guide may help: How to Improve Airflow in Your HVAC System.

Thermostat Placement and Settings Matter

Thermostats control your entire heating system, so even small issues can affect how long the heater runs. If the thermostat is located near a drafty window, exterior wall, or an area that gets direct sunlight, it may read temperatures incorrectly.

This can cause the system to run longer than necessary or cycle more frequently. Incorrect schedules or frequent manual adjustments can also make the system work harder than needed.

Sometimes the issue is as simple as recalibrating the thermostat or updating the temperature schedule.

You can also review this article to understand thermostat-related issues: How to Tell If Your Thermostat Is the Reason Your Heating Isn’t Working.

Insulation and Heat Loss Inside the Home

Another common reason heaters run constantly is heat loss. Even in Southern California, homes with older insulation or single-pane windows may lose heat faster than expected.

Warm air naturally rises and escapes through ceilings, attics, and poorly sealed windows or doors. When this happens, the heater must keep running to replace the lost heat.

Drafts around doors, gaps in attic insulation, and aging weather stripping are often responsible for this type of heat loss. Many homeowners notice that the heater runs longer at night or early in the morning when outside temperatures are lowest.

Simple Things You Can Check Yourself

Before calling a technician, there are a few simple steps you can take:

• Check and replace the air filter if needed
• Make sure all supply vents are open and unobstructed
• Verify thermostat settings and schedules
• Check doors and windows for drafts

These quick checks often resolve minor issues and improve system efficiency.

When It’s Time to Call a Professional

If your heater runs constantly and your energy bills are rising, there may be deeper issues such as duct leaks, worn components, or a system that needs calibration. These problems are common and usually easier to fix when detected early.

Regular maintenance helps prevent performance issues, improves energy efficiency, and extends the lifespan of your equipment.

If your heater is running longer than it should, call (949) 229 6766 or schedule a service visit today.