Your HVAC system is a lifesaver. It warms your home during the coldest winters and it cools your home during the long summers. We rely on our HVAC systems so much that sometimes when things out of the ordinary start to happen, we can’t help but freak out. The first thought is that the system has a major issue and you will be freezing in the winter.

If you have ever encountered a smell coming from your HVAC system do not be alarmed just yet. We will explain what smells are a sign of “bad news” and what smells are simple fixes.


This is one of the most common HVAC smells and it is a simple fix. The moldy smell is a result of the condensation within the unit. When water does not drain properly it allows mildew and mold to grow. What can you do? Call us to find the mold buildup and we will clean it up.


It might be your own garbage, but it could also be your HVAC system. The smell of rotten garbage is usually a sign of a small dead animal whose body has begun decomposing.

Cigarette Smoke:

If you or anyone in your home smokes, chances are that the fumes are now stuck in the condenser coil. Once that happens, the coil permeates the old cigarette smoke every time you use your air conditioner. Just cleaning the coil can get rid of this problem.

Rotten Egg:

Usually, the smell of rotten eggs means that there is a natural gas leak. If you are smelling, it might be because the leak is close to your air ducts. As soon as you smell it, leave your home and call the gas company since this could be a very dangerous situation.


This one is also a problem. The smell could be caused by a ruptured sewer vent pipe or a backed-up sewer line. Please call us right away to fix this issue.

Burning/Gun Powder:

These smells indicate a problem with the AC fan, compressor, AC motor, or circuit board. Immediately turn off your system to avoid a fire. And then give us a call!

As you see while some smells could be innocent, other smells could be incredibly dangerous. Our advice is to always call Complete Heating and Cooling as soon as you notice any weird smells. Avoid using your system and allow us to fix it!