Re: What could cause a sulfur smell to come out of my air conditioning ducts

Mimi,

You did not specify what type of heater or air conditioning system you have - it 
is pretty important to the answer.  If your heater is fired by natural gas, you 
may want to get your local gas company to come and see if they can find a 
possible leak in the gas system.  Most companies do this free of charge.  If it 
is fired by propane, the same possibility exists.  However, if you have an all 
electric system, your problem can be one of a few things.  If the smell occurs 
after the systems have not run in a while, say, between heating and cooling 
seasons, and lasts only a few minutes, it is just mold that has started to grow 
in the ducts and you are moving the bad air (certain molds, and bacteria give 
off odors as waste products) out of the system.  If it is a continuous smell 
even after the systems have run for 2-3 hours, your problem will most probably 
be related to a dirty air system.  You may want to have an air conditioning 
company come out and see if there is dirt and lint and other material on the 
inside of your ducts.  This problem usually occurs in older house.

I hope this helps.  If not write back again with a few more details.

Carlin Gregory
Staff Chemist
Williams Gas Pipelines, SouthCentral