Top 5 Most Common Furnace Problems Homeowners Face (And When to Call for Furnace Repair)

If you rely on a furnace to keep your home warm during the colder months, understanding the most common furnace issues can help you avoid unexpected breakdowns. For homeowners in Santa Rosa, Modesto, and Fresno, CA, as well as Post Falls, ID, seasonal temperature swings mean your heating system needs to perform reliably. Below are the top five furnace problems we see most often—and when it’s time to call for professional residential furnace services from Next Day Air & Heating.

1. Dirty or Clogged Furnace Filters

One of the most common causes of furnace trouble is a dirty air filter. When filters become clogged with dust, pet dander, and debris, airflow is restricted. This forces your furnace to work harder, which can lead to overheating, reduced efficiency, and even system shutdown.

In areas like Fresno and Modesto where dust levels can be high, filters may need to be replaced every 1–3 months. In colder climates like Post Falls, ID, where furnaces run consistently through winter, regular filter changes are equally important to maintain proper airflow and protect internal components. If your furnace is short cycling or struggling to heat your home evenly, it may be time for a filter replacement—or a professional inspection.

2. Ignition or Pilot Light Problems

Modern furnaces use electronic ignition systems, while older units may rely on a standing pilot light. If your furnace won’t start or is blowing cold air, ignition failure could be the culprit. Faulty flame sensors, worn igniters, or gas supply issues are common causes.

Ignition problems should always be handled by a licensed HVAC technician. If you notice clicking sounds, delayed ignition, or a furnace that repeatedly attempts to start, it’s time to schedule professional furnace repair services to prevent further damage.

3. Thermostat Malfunctions

Sometimes the furnace itself isn’t the issue—the thermostat is. A malfunctioning thermostat can cause inconsistent temperatures, short cycling, or a system that won’t turn on at all.

With many homeowners upgrading to smart thermostats in Santa Rosa and surrounding areas, incorrect programming or wiring can also lead to performance problems. If your furnace isn’t responding properly, a heating professional can diagnose whether the issue lies in the thermostat, electrical connections, or the furnace control board.

4. Blower Motor or Airflow Issues

The blower motor is responsible for circulating warm air throughout your home. If you hear unusual noises like squealing, banging, or rattling, it could indicate worn belts, motor bearings, or loose components.

Restricted airflow can also be caused by ductwork issues, especially in older homes. Poor airflow reduces comfort and increases energy bills. Regular furnace maintenance helps identify these problems early before they lead to complete system failure.

5. Frequent Cycling or Rising Energy Bills

If your furnace turns on and off frequently (short cycling) or your heating bills are climbing without explanation, your system may be struggling. This could be due to overheating, airflow restrictions, aging components, or an improperly sized furnace.

In colder regions like Post Falls, ID, an overworked furnace may show signs of wear more quickly due to extended winter operation. In California’s Central Valley and Bay Area, fluctuating temperatures can also stress heating systems. If your unit is over 15–20 years old and frequently breaking down, it may be time to consider a furnace replacement rather than repeated repairs.

Schedule Residential Furnace Services with Next Day Air & Heating

If you’re experiencing any of these common furnace problems, don’t wait for a full system breakdown. The experienced technicians at Next Day Air & Heating provide trusted residential furnace repair, maintenance, and installation services in Santa Rosa, Modesto, Fresno, and Post Falls, ID.

From diagnosing minor airflow issues to performing complete furnace replacements, our team ensures your home stays safe, comfortable, and energy efficient. Contact Next Day Air & Heating today to schedule professional furnace service and keep your heating system running at peak performance all winter long.