Spooky Science: Why is Fog Coming From My Air Conditioner?

Spooky Science: Why is Fog Coming From My Air Conditioner

At Brown Heating & Cooling, we sometimes get calls from homeowners concerned that they have a major problem on their hands. When they turn their air conditioning on, they suddenly experience a spooky scenario – it’s almost like they have their very own fog machine! Usually this fog is odorless, so it’s doesn’t flag as smoke, but it can be a little disconcerting for people who have never seen this phenomenon.

As we all know, Alabama can be a very humid place. Sometimes, when the conditions are just right, the air coming from your A/C unit is drier than the warm, moist air near the vent opening. When the cold dry air comes in contact with the warmer, more humid air, causing water vapor to form and condense into visible droplets, or what we know as “fog.” It’s harmless, and generally doesn’t indicate a major problem with your HVAC system.

How can you make the fog go away? Try running your system on high for a few minutes – this will help to balance the humidity differential more quickly, and the fog should disappear on its own.

That said, sometimes this phenomenon can be aggravated by a dirty air filter. Particulate matter helps to condense the water vapor, so fog can be a sign of air that isn’t at its cleanest. Your air filter is probably the first thing you should check if you notice this issue occurring on a regular basis. Depending on your HVAC system and how often you rely on air conditioning, your air filter should be replaced every 1-3 months.

While odorless fog is not a problem, any type of smoke that has an odor or stays around for a long period of time is definitely a problem! In that case, we recommend turning off your HVAC system completely and giving us a call so we can assess the problem.

Happy Halloween!