When the temperatures drop Lubbock, a reliable furnace isn’t just nice to have—it’s essential. Most furnace troubles announce themselves with clear symptoms, and knowing how to troubleshoot them can save you time, money, and discomfort.

While some issues require calling a professional, many common problems have simple, DIY solutions. At Nugent Mechanical, we want you to be prepared! Here are the most frequent furnace issues and what you can do to address them.

 

Problem 1: The Furnace Isn’t Producing Heat (or Won’t Turn On)

This is the most common and immediate crisis, especially during a cold snap.

Likely Cause Your DIY Fix When to Call Nugent Mechanical
Thermostat Issues Make sure the thermostat is set to “Heat” and the temperature is set at least five degrees higher than the current room temperature. Check or replace the batteries if it’s a digital unit. If the screen is blank or the thermostat won’t trigger the furnace after checking the batteries.
Tripped Circuit Breaker Go to your main electrical panel. If the breaker is flipped, reset it by turning it completely OFF, then ON. If the breaker immediately trips again, this indicates a dangerous electrical short and requires professional attention.
Furnace Power Switch Check the emergency switch (often a red switch near the furnace or in the basement/attic). Ensure it is set to the “ON” position. If the switch is on but there’s still no power to the unit.
Clogged Air Filter A severely dirty filter restricts airflow, causing the system to overheat and shut down as a safety precaution. Replace the filter immediately. If replacing the filter doesn’t restart the unit.

 

Problem 2: The Furnace is Blowing Cold Air

Your blower is running, but the air coming out of the vents isn’t warm.

  • Pilot Light/Ignitor Failure (Gas Furnaces): If the pilot light is out (or the electronic ignitor fails), the furnace can’t burn gas to create heat. You can try to safely relight the pilot light following the instructions on your furnace, but if it won’t stay lit, the thermocouple may be faulty.
  • Dirty Flame Sensor: This safety device ensures the gas valve is closed if the burner flame goes out. If it’s covered in soot, it mistakenly senses no flame and shuts off the gas, resulting in cold air. A technician can safely clean or replace this sensor.
  • Overheated Unit: The heat exchanger may be so dirty (or the filter so clogged) that the furnace is immediately hitting its safety limit and shutting off the burner.

When to Call: If the pilot light won’t stay lit, or if the unit is repeatedly cycling on and off.

 

Problem 3: Strange Noises Coming from the Furnace

Your furnace should run quietly. Any new or loud sounds indicate a component is failing or broken.

Noise What It Likely Means
Squealing or Chirping Usually indicates a problem with the blower motor belt (needs lubrication or replacement) or a failing motor bearing.
Banging or Popping Often caused by expanding/contracting ductwork as the temperature changes, or sometimes by delayed ignition in the burners.
Rattling Could be a loose panel or screw that needs tightening, or debris inside the blower fan.

When to Call: If the noise is loud, persistent, or accompanied by a loss of heat. Worn belts and bearings put extreme stress on the motor and need immediate repair.

 

Problem 4: High Energy Bills

The furnace seems to be running fine, but your utility bill is unusually high.

  • Lack of Maintenance: This is the biggest culprit. An unmaintained furnace can lose up to 5% of its efficiency each year it goes without a professional tune-up.
  • Old Filter: A dirty filter forces the motor to run longer, wasting energy.
  • Poor Insulation/Drafts: Your home itself may be losing heat through drafts or poor attic insulation, forcing the furnace to run constantly.

 

Your DIY Fix: Enroll in a preventive maintenance plan and consistently replace your air filter every 30–90 days. Check windows and doors for drafts.

 

When to Trust the Professionals

While DIY fixes are great for simple issues like filters and switches, leave anything involving gas lines, electrical components, or internal repairs to the certified technicians at Nugent Mechanical. We use specialized diagnostic tools to locate the problem quickly and safely, ensuring a lasting repair.

Don’t ignore the warning signs! Contact us today for reliable service that keeps your furnace running efficiently and safely all winter long.