New Kitten allergic to Air Conditioning!!

Ok, so this past thurs I adopted a new kitten (4mo old Male.) He came home with some sneezing.
I called the vet and they told me how common it was and he'd be fine. I made an appointment for him with the vet for Monday (today). But he was getting worse and worse, so when I got home from work Saturday morning, I rushed him to the kitty ER.
They gave him a shot of antibiotics and told me I should sit with him in the bathroom with hot shower running so the steam would help him breathe easier. They also told me to cut off the air conditioning and open up the house to let it air out, and also get him some humidity.
He seems to be bouncing back pretty well. He is eating, using the litter box, playing, and getting into normal kitten mischief.
So today is supposed to be way HOTTER than it was over the weekend. So I turned on the AC (only up to 80°)
But within 5 minutes of turning it on he started sneezing and wheezing all over again.
I have COPD myself. So there's a new filter on the AC intake, and I've got the individual vent filters throughout the house. I vacuumed and mopped the kitchen and bathroom floors before I brought him home. I don't know what else to do.
Any suggestions??

Thanks in advance!!

He may have allergies to the dust and what not that is circulating when the air is on. I would recommend seeing a vet so they can tell you what to use to help treat the allergies and ensure it is not asthma.

I had to do some power-washing today. So, of course, I had to close up the house and turn the AC back down. And, while he did sneeze twice at first, there was no weezing, congestion or change in his behavior.
And the sneezing only occurred when I very first turned on the air, and he ran to the vent to investigate...
So, I'm happy to report that all seems well for the moment.

I will definitely keep you updated.

PS-I did contact the vet, and he told me that I needed to give him time to acclimate to his new environment. Especially since he's coming from shelter with such poor ventilation

Thanks for updating.  It sounds like his URI was complicating things - I really hope this is resolved now.  Congratulations on your new kitten, btw! 

@Panda 925  We had similar issues too. On top of changing out the AC filter and doing deep cleaning, we added an air purifier with hepa filter. 

Yeah, I have actually been doing some research on air filters & humidifiers for both me and Simba. From everything that I've read, in order to get one that makes a noticeable difference you've really got to spend some serious money. But the way things are going, it's going to have to be done. Maybe I'll find a second hand one on Craigslist sometime before winter rolls around...