What’s That Smell Coming From My HVAC System?

If you take a moment to consider the complexity and sophistication of modern HVAC systems, it’s a wonder they malfunction as rarely as they do. When HVAC problems do crop up, they’re usually accompanied by a variety of distinctive smells. Here are a few unusual odors to look out for that may signal the need for a minor or significant HVAC repair in the immediate future.

Wet Newspaper

One HVAC smell you’re guaranteed to encounter at some point is that of mold and mildew. More often than not, this lovely odor is caused by a backed-up condensate drain line. If the condensate line doesn’t drain properly, mold can rapidly proliferate throughout the HVAC system. Clearing the condensate drain line won’t always solve the dilemma. You may need to thoroughly clean ducts to get rid of the smell.

Auto Exhaust

Modern HVAC units rely on a variety of fluids to deliver superior heating and cooling. If one of those fluids is leaking, you’ll be able to smell it in short order through the vents. A smoky HVAC smell associated with leaking fluids can indicate that indoor air is contaminated with harmful particles. Furthermore, an exhaust smell is a good sign that a major repair is needed.

Burnt Plastic

Once you’ve smelled a failing electric motor, you’ll never forget the odor. It’s an HVAC smell that’s unlike any other you’re likely to encounter. The smell of burnt or burning plastic can indicate a variety of complications. Broken wire insulation resulting in a short circuit could be one culprit. Failing motor bushings could be another. Long story short, these smells should be investigated by a competent HVAC professional.

Expired Eggs

Generally speaking, the smell of sulfur is never a good sign, even if you encounter it far away from HVAC hardware. Rotten eggs are an HVAC smell that often points to a natural gas leak. If you smell rotten eggs, killing the gas and turning off the power is a good idea. Contacting an HVAC specialist to troubleshoot the issue as soon as possible is an even better idea.

Chemicals of Any Kind

A malfunctioning HVAC system will emit a variety of unusual smells when something is wrong. If your central HVAC unit or the air coming from the ducts smells like a high school chemistry lab or a garage, you need to address the trouble ASAP. You might smell turpentine or formaldehyde when a major issue crops up, depending on the make and model of your HVAC unit.

What to Do When You Detect a Potential HVAC Smell

Unless there’s a plausible alternate explanation for any of the smells mentioned above, you probably have an emerging HVAC issue that requires your attention. Do yourself a favor and call in an HVAC specialist quickly to size up the problem. By getting ahead of the situation, you’ll potentially save yourself thousands in repairs in the long run. When it comes to an awful smell, the nose never lies.

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