Common Signs Your HVAC Needs Replacement
Weak or No Airflow
What is the problem?
Air is either barely coming out of your vents or has stopped entirely, making it impossible to maintain a comfortable temperature in your home.
What caused it?
This is usually caused by a heavily clogged air filter restricting flow or a blower motor that has worn out and can no longer push air through the ductwork.
Will it happen again?
With regular filter changes every 30–90 days, you can prevent most airflow issues. However, mechanical parts like motors will eventually reach their end-of-life.
Unit Running But Not Cooling
What is the problem?
Your HVAC system is powered on and humming away, but the air blowing through the house isn’t actually cold.
What caused it?
The culprit is often a miscalibrated thermostat or a failing compressor. Because so many different components can cause this, a professional “Monster” diagnostic is usually required.
Will it happen again?
Electrical components like thermostats can fail due to age, but keeping your outdoor unit clear of debris helps protect the compressor from overworking and failing prematurely.
Refrigerant Leak
What is the problem?
Your system is losing the “coolant” it needs to remove heat from your home. This forces the unit to run longer cycles while producing less cooling.
What caused it?
Leaks typically develop over time due to formicary corrosion (pitting in the copper coils) or vibrations that cause connections to loosen and crack.
Will it happen again?
Simply “topping off” the refrigerant is a temporary fix. Unless the leak is found and sealed, the refrigerant will continue to escape until the system fails again.
Frozen Outdoor Unit
What is the problem?
Ice has physically built up on your outdoor coils or brass refrigerant lines, even when it’s hot outside. This effectively “insulates” the unit against doing its job.
What caused it?
This is typically triggered by restricted airflow (dirty coils/filters) or low refrigerant levels, both of which cause the coil temperature to drop below freezing.
Will it happen again?
If the underlying airflow or leak issue isn’t resolved, the unit will likely freeze up again within hours of the ice melting.
Loud Noises or Vibrations
What is the problem?
Your system is making unusual sounds—like banging, screeching, or buzzing—or you can feel the unit vibrating through the walls.
What caused it?
These are warning signs of mechanical distress. It could be something as simple as a loose fan blade or as serious as a motor bearing failing or a compressor “slugging.”
Will it happen again?
Mechanical noises rarely go away on their own; they usually get louder until the part fails completely. Early intervention prevents a small noise from becoming a total system replacement.