The mold is always a possibility wherever there is moisture. You could start by checking the coil. Look for black mold spores.

A properly-installed and maintained HVAC system should not be growing mold, but there are always problems that crop up. Look in your ducts and open up your air handler and look in there. Take pictures and report back.

You might find this book useful:

My House Is Killing Me!: The Home Guide for Families with Allergies and Asthma

Jeffrey C. May

also Healty House by John Bower.

anywhere you have moisutre and a food source..
like condensation and dirt..you have potential
for mold.

look inside ahu, inside return, and inside
ducts by removing supply grills.
lots of time mold will grow at duct take offs
at the plenum where the take offs are not mastic
sealed. dirty air is pulled in, condensation forms
and mold will grow inside plenum and ducts near
plenums. the mold will spread as far inside the ducts
as the moisture and food source reaches.

best of luck.

Great tips! I took a look in the ducts and did not see anything. I think I will have them cleaned though. I don't see anything blowing out when the A/C is on. My allergy problems could be coming from elsewhere but I thought I would ask.

Robin, if you have not been allergy tested, you probably should do it. Beyond making sure that your "home hygiene" is stringent, that is the most important thing. You can't approach a problem without defining it.

Duct cleaning is overrated. You really need to have a look inside the air handler at the AC coil and drip pan.

"Look for black mold spores."

Be sure you use a microscope.