What’s that smell?

You may have run this internal monologue through your head recently: What’s that smell? It smells like something’s burning. No, that’s not it…Am I breathing poisonous gas?

Fortunately, we’re here to tell you that the answer is (most likely) no. This time of year, we start getting a lot of calls about funky smells in people’s offices, apartments, etc.

More often than not, these funky smells are usually associated with your air conditioning system stretching its legs for the first time this season. Here are some of the most common explanations for those unappetizing odors—and a few scenarios when you may need to call in an expert.

Dust has accumulated

If you’re experiencing a burning smell, the most likely cause is that dust has settled within your HVAC. When the system kicks on and warms up for the first time in months, dust that has built up on your circuit boards, power wires, fans, compressors, etc. may start to burn off and emit an unpleasant odor.

This smell should only be temporary and will disappear after most of the dust has been burned off. That said, if the odor doesn’t go away after a couple of hours, or it smells like gunpowder or plastic burning, you should turn off your system and contact an HVAC specialist. These signs indicate that an actual component may be burning (not dust) and needs to be repaired or replaced.

Your air filter needs to be replaced

With all of the water vapor, dust, bacteria and other particles that can get trapped in your air filters (or at least we’d hope so, since that’s they’re purpose), the potential for mold and mildew growth should come as no surprise. If you’re experiencing a musty odor, see if replacing your air filter fixes the problem. Ideally, air filters should be changed every 3 months (and even more frequently if you have pets).

It is also important to replace air filters regularly because an overly clogged filters can place an extra work load on your HVAC system and cause other parts to wear down faster.

Mold or mildew growth

If you have changed your air filter and are still experiencing a musty smell coming from your HVAC, you may have moisture accumulation in other parts of your HVAC. Water and water vapor can collect and condensate in the drain pan, drip lines, or ducts and lead to mold and mildew growth.

To help prevent mold and mildew growth, empty your HVAC drain pan in the fall before you shut down you system for the winter. It also doesn’t hurt to wipe down HVAC components with a little bit of diluted bleach in the spring before you put your system into use.

Foul or rotten smells

If you have a foul or rotten smell coming from your HVAC, there are two possible causes.

The first is that a critter or pest may have made its way into your system and gotten stuck. Whether is a bird, rodent, lizard, or insects, the only real way to get rid of this odor is to remove the trespassing creature.

The second (more worrisome) possibility is that you may have a gas leak getting into your ductwork. While natural gas doesn’t have a distinct smell on its own, utilities providers have added chemicals that emit a distinctive rotten or skunk-like odor to help us identify leaks. If you think this may be the issue, you should turn off your gas supply immediately and contact your utility provider to come and fix the issue.

Conclusion

In sum, funky smells coming from your HVAC can be worrisome. In high-risk environments (like hospitals), unfamiliar odors can be an immediate cause for concern and should be investigated by and IAQ specialist, Industrial Hygienist, or HVAC specialist as soon as possible. In lower risk settings, it may be okay to wait a day are so to see if the issue is simply a dusty system. Regardless, keeping your HVAC system clean and your filters fresh is always a good idea. If you have concerns about your HVAC as we enter cooling season, please do not hesitate to reach out to reach out to Dan Taylor at dantaylor@amienvironmental.com or 402-981-1000.

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