When your HVAC system starts making unusual noises, it’s often a sign that something isn’t right. As winter settles in, the last thing you want is for your heating system to break down in the middle of a cold night. If you hear any strange HVAC noises when the heat is on, don’t ignore them—some sounds could indicate serious issues that need immediate attention.
In this blog, we’ll cover the most common HVAC noises you should never ignore, what they mean, and how to address them. If your system is acting up, Boyle Energy is here to help with expert heating and air conditioning repair services in Delaware County and surrounding areas.
1. Banging or Clanking Sounds
Possible Causes:
- Loose or broken internal parts (e.g., blower fan, motor mounts, or heat exchanger)
- A misaligned blower wheel
- Debris inside the unit
What to Do: Turn off the system immediately and call a professional for an inspection. If left unattended, a broken part could lead to a complete system breakdown.
2. Rattling Noises
Possible Causes:
- Loose screws or panels
- Ductwork expansion and contraction
- A failing blower motor
What to Do: If your HVAC is making a rattling noise, check for loose panels and tighten them. If the noise persists, call a heating repair technician to inspect the motor and ductwork.
3. High-Pitched Screeching or Squealing
Possible Causes:
- A worn-out blower belt
- Motor bearing issues
- Fan motor problems
What to Do: If you hear squealing when your heating unit is on, schedule a service appointment. Lubricating the motor bearings or replacing the blower belt can resolve the issue.

Want To Know How We Deliver Ultimate Comfort Experience?
- Faster HVAC installation & maintenance in Havertown, Newtown Square, and Philadelphia area
- Reliable oil delivery services & competitive payment plans
- Timely propane delivery and seamless equipment installation
4. Loud Booming or Popping
Possible Causes:
- Delayed gas ignition (in gas furnaces)
- Expanding and contracting ductwork
What to Do: A booming sound could indicate a dangerous gas buildup in your furnace. This is a serious safety risk—turn off your system and call for emergency HVAC repair immediately.
5. Humming or Buzzing
Possible Causes:
- Electrical issues (e.g., faulty capacitor or wiring problems)
- Loose components
- A failing motor
What to Do: If your HVAC is making a buzzing noise, it could signal an electrical problem. Do not attempt to fix this yourself—contact a professional HVAC technician to check the system.
6. Whistling or Hissing
Possible Causes:
- Air leaks in ductwork
- A clogged air filter
- Refrigerant leaks (in heat pumps)
What to Do: First, replace or clean the air filter. If the noise continues, have a professional inspect your ductwork and refrigerant lines.
Why Prompt Repairs Matter
Ignoring unusual HVAC noises can lead to:
✔ Higher energy bills
✔ More costly repairs
✔ System failure during peak winter months
Call Boyle Energy for Expert Heating Repairs
Strange noises from your HVAC system are often warning signs of underlying mechanical issues. Whether it’s a banging, rattling, whistling, or screeching sound, addressing the problem early can prevent costly repairs and unexpected breakdowns.
At Boyle Energy, we understand how crucial a properly functioning heating system is during winter. Our expert technicians are ready to diagnose and fix any HVAC issues, ensuring your home stays warm, efficient, and safe all season long. Don’t wait—schedule your HVAC inspection today call Boyle Energy at 610-347-5197.

Experience unparalleled comfort year-round!
Ensure your home stays cozy with our expert Havertown HVAC service and tune-up

Patrick Boyle brings over three decades of expertise to Boyle Energy, carrying forward a family legacy that began with his grandfather, Joseph Boyle Sr., the company’s founder. With extensive technical proficiency, Patrick holds advanced certifications in both oil and HVAC systems, ensuring the highest standards of service and performance. Additionally, he is recognized as an NPGA-certified propane service professional, underscoring his commitment to safety and industry best practices. Under his leadership, Boyle Energy continues to deliver reliable and efficient energy solutions, grounded in generations of trust and innovation.