A burning smell from your furnace may indicate several issues, including:
Accumulated dust: Burning off dust that has settled on the furnace components during periods of inactivity.
Dirty air filters: Overheating due to restricted airflow caused by dirty filters.
Mechanical problems: Issues with the motor, belts, or electrical components.
Blocked vents: Obstructions preventing proper airflow.
It's essential to address the cause promptly to prevent potential safety hazards and ensure the furnace operates efficiently and safely.