Help! I've had quite the AC saga over the last year and I really want it to be over. I live in a rural area where its getting one contractor is difficult, let alone multiple for bids/second opinions. 

Beginning last summer I noticed water in the drip pan and it seemed like the larger unit was getting condensation on it. Because the insulation was wet and needed to be dried/replaced it was going to be just as expensive as getting a new unit, so the two year old AHU was replaced. For additional context I believe the outside unit was replaced 8 years ago.

The smaller AHU was also having issues causing water to overflow into the drip pan, so it too was replaced. The whole system was still Freon-based, so we had to replace the outdoor unit too. It had a leak and we had folks out three times before it was finally (hopefully) fixed. 😩

Now, about a year after the AHU was replaced I noticed the large unit has visible confensation again. It's possible it was doing it previously but the issues with the small unit masked it. Additionally, it's only been warm here the last 3 months. I only noticed the water when I heard the drain gurgling as the air turned off. I assume since we've been through this already that it's something to do with the attic configuration as some of the building around it happened after the home was initially built. The smaller unit is not getting condensation. 

Our contractor suggested adding a fan to test if that helped, and if so we could perhaps raise the unit or wall off the space with both units to climate control it better. That seems to have resolved the condensation for now. However, after our contractor spoke to the manufacturer, it is now suggested the we change the termostat. We have a Nest which I know has its issues, but it doesn't seem to cause the system excessively run or anything, so curious as to whether that's an actual solution or just grasping at straws. We use the same thermostat for the other unit which also doesn't seem to be causing issues. 

I had read on previous posts to use a smaller MERV filter, so we use a MERV 5 and change every 4 weeks pretty religiously. I also read to raise the set temparature, so we have gone from 70 to about 72-74. 

I live in a very humid area of Texas we're 70% is a good day. It seems most plausible to me that the moist air is just doing its thing when it contacts the cold unit, so it seems like ventilation and/or walling off this space would be our best option. I'm not opposed to changing the thermostats which is a small expense after the five figures we've spent over the last year, but really would like permanent resolutions because I'm going nuts with constant AC issues! 


Help with our air handler condensing