Common Furnace Problems and How to Fix Them
A furnace is an essential part of your home’s comfort system, especially during the colder months. However, like any appliance, furnaces can encounter issues that disrupt their performance. At RMR Heating and Cooling, we want to empower homeowners with knowledge about common furnace problems and how to address them effectively.

Why Understanding Furnace Issues Is Important

Recognizing common furnace problems early can save you from costly repairs, improve energy efficiency, and ensure your home stays warm and comfortable. While some issues require professional assistance, others have simple fixes that you can handle on your own.

1. Furnace Won’t Turn On

Possible Causes:

  • Thermostat settings are incorrect.
  • The circuit breaker has tripped.
  • A safety switch on the furnace door is open.

How to Fix It:

  1. Check the thermostat and set it to “Heat.” Ensure the temperature is set higher than the current room temperature.
  2. Inspect the circuit breaker panel and reset any tripped breakers.
  3. Ensure the furnace door is securely closed, as the safety switch may prevent the furnace from turning on.

Pro Tip: If these steps don’t work, contact RMR Heating and Cooling for professional diagnostics.

2. Insufficient Heat

Possible Causes:

  • Dirty air filters restricting airflow.
  • Blocked or leaky ductwork.
  • A malfunctioning thermostat.

How to Fix It:

  1. Replace the air filter if it’s dirty or clogged.
  2. Inspect ducts for visible blockages or leaks and seal them with duct tape or mastic sealant.
  3. Test the thermostat by adjusting the temperature settings. Replace the batteries if needed.

Pro Tip: Schedule a professional inspection to rule out internal furnace issues.

3. Furnace Blowing Cold Air

Possible Causes:

  • Pilot light is out (in older models).
  • The gas supply is turned off.
  • A malfunctioning flame sensor.

How to Fix It:

  1. For older models, relight the pilot light following the manufacturer’s instructions.
  2. Ensure the gas supply valve is turned on.
  3. Clean the flame sensor gently with a soft cloth or fine-grit sandpaper.

Pro Tip: If the problem persists, a professional technician can test the gas valves and flame sensors.

4. Frequent Cycling (Turning On and Off)

Possible Causes:

  • A clogged air filter.
  • An oversized furnace.
  • Issues with the thermostat.

How to Fix It:

  1. Replace or clean the air filter.
  2. Ensure the thermostat is placed away from heat sources like direct sunlight.
  3. If your furnace is too large for your home, consult an HVAC professional about potential solutions.

Pro Tip: Frequent cycling can strain your system and increase energy costs—don’t ignore it.

5. Strange Noises

Possible Causes:

  • Rattling may indicate loose components.
  • Whistling often points to clogged filters.
  • Banging could mean ignition delays.

How to Fix It:

  1. Tighten any loose panels or screws.
  2. Replace dirty air filters to improve airflow.
  3. If you hear banging, turn off the furnace and call a professional to inspect the ignition system.

Pro Tip: Regular maintenance can prevent many noise-related issues.

6. Furnace Won’t Shut Off

Possible Causes:

  • A faulty thermostat.
  • A blower motor issue.
  • Incorrect thermostat settings.

How to Fix It:

  1. Lower the thermostat setting to see if the furnace responds.
  2. Check the fan setting—ensure it’s on “Auto,” not “On.”
  3. Contact a professional to inspect the blower motor if the issue persists.

Pro Tip: Running your furnace continuously can increase wear and tear—address this issue promptly.

7. High Energy Bills

Possible Causes:

  • Poor furnace efficiency.
  • Dirty components.
  • Leaky ducts or inadequate insulation.

How to Fix It:

  1. Replace air filters and clean the furnace components.
  2. Seal any visible duct leaks and consider adding insulation to your home.
  3. Schedule a professional tune-up to improve efficiency.

Pro Tip: Investing in an energy-efficient furnace can save money in the long run.

Conclusion

Understanding common furnace problems and their solutions can save you time, money, and stress. Whether it’s a minor issue like a dirty filter or a more complex problem like a faulty blower motor, addressing furnace issues promptly ensures your home stays warm and comfortable all winter long.

At RMR Heating and Cooling, we’re here to help. Contact us today for professional furnace repairs, maintenance, and expert advice. Let’s keep your furnace running smoothly all season!