HVAC Odors to Keep a Nose Out For

We normally associate residential HVAC equipment to fresh air, but sometimes it just plain stinks. Although not all unpleasant smells indicate something serious by nature, they nevertheless need to be investigated.

HVAC Odors to Keep a Nose Out For

If you notice any of the odors listed below, be sure to troubleshoot the underlying issue ASAP.

Burning Metal

When turning on your heating unit for the first time in a while, it may emit an electrical smell. This odor typically dominates the air as your HVAC equipment burns off the dust that’s collected on it since you last used it. Just wait it out because it should go away after 30 minutes.

If the metallic smell lingers, that suggests that something is overheating. When a furnace blower motor generates more heat than usual, the extreme temperature may melt the wires, producing the burning odor. You’ll need to call in an HVAC technician to get this repaired.


The smell of urine coming from air registers usually points to rodent infestation. It means that your ducts have become a mice lair. Needless to say, the pests in your house have to be exterminated, and your ductwork will need to be sanitized to prevent the spread of germs.


Does the air emanating from your furnace or air conditioner smell like rotting garbage? This smell is a good sign that something is decomposing in the ducts. The logical explanation for the rotting smell is that the carcass of a dead animal is lurking somewhere in your HVAC system. You’ll need to call in someone to locate and remove the carcass for you and clean and sanitize the ducts.

Stale Air

One of the very few consequences of living in a weathertight house is a lack of airflow. If your rooms don’t have adequate natural ventilation or mechanical ventilation devices to compensate for this, pollutants can affect your indoor air quality.

Be Aware of Unpleasant Residential HVAC Odors

To prevent residential HVAC problems from happening right under your nose, pay attention! Call Sierra Air at (775) 800-5500 to schedule an appointment any time you smell anything out of the ordinary coming from your heating or cooling system.