Be kind. I'm not an Airhead nor a chilled wet head. But I have questions.
Where I live now in Florida I bought in 2005. The AC was replaced in 1996 to replace something that was installed in 1982 with some sort of hot water recovery HP unit that had failed. Same usual slam it in system. Louvered door in a closet where the AC is, supply ducted to an unconfined attic space with flex duct. Someone lived here year around (from 1982) until we bought it in 2005. There were no signs of water damage to the ceilings around ceiling grills. If there had been, I would have noticed it. After a few years, I noticed a wet spot on the ceiling above and in front of the unit. I went up into the attic and wrapped it with more insulation and covered the duct work with more batt insulation. Which mostly stopped that. There was never any ceiling wet staining around the ceiling grills until last June (2013) when we moved here. I noticed the ceiling staining, but no worse where I had originally seen it. In other words, it wasn't leaking. At over 100 degrees the old unit would cycle on and off all day with the cooling at 78 or 77. We keep it at 79 mostly. Last Fall (October), I had it serviced. It was fine. I asked them about replacing the attic duct because of the wet spots, it was falling apart, it was 30 years old, and I wanted it upgraded. I asked them to use R-8 duct but they told me that no one around uses it and it had to be special ordered from the supply house. They used R-6 like everyone else. Turned out what I thought was R2 or R4 was actually R-6 anyway. They replaced all the flex board boxes with bigger, better and thicker ones.
While I have the money, and not wanting to face a expensive replacement 5 years down the line on a 15+ YO system, I asked them to replace it. They did a fine job. There was an issue with the new unit inside. The old unit had the intake on the bottom. Its above a water heater. The unit to replace the old one was a 10 SEER (or less from age) and the best they could give me was 14 SEER because of a height limitation through the door. I came up with using steel flat stock across the closet walls but the installer went with two pieces of hanger stock and put a cover plate and moved the intake/filter to the front where I assume it is also designed to go. It is much noisier from an airflow point than the old unit. The ceilings are staining. the unit never shuts off when the temperature is over 98 degrees OAT. It used to cycle at over 100 degrees with 77 degree inside air and not sweat. I get plenty of air from the ceiling registers, the wet isn't dripping out of the vents, it is forming on the metal in the room. It seems like there isn't enough air flow? There is much room for unrestricted air flow when the air enters from the side than would be from the bottom.
There's a lot of things that I could do but it isn't working like the old one. Yesterday, the compressor stopped for unrelated reasons. The installer came and got it going. I told him that the thing didn't work well at all, That my electric bill compared to last year with the old unit was half again as high per KWH, attributable to the AC. He said that it should go down to 75 degrees and cycle. It goes down to 79 and won't cycle. At 12:00 PM.Noon, it was 84 degrees out, and 82 in the house. I turned the thermostat to 79. The OAT went to just over 99 degrees. It has now dropped 94 degrees OAT. it went to 79 degrees after three hours and hasn't stopped running since.
What am I missing? Lack of heavy airflow to be moving air and drying it out? Is the big plastic fan cage in the well known manufacturers unit just not moving enough air? Is it too fat and restrictive in side the return box? I wish they had put in another Rheem unit. I'm suspicious of this. I know that WA/AC units like Plenums. A return plenum is out of the question. Every one of the 240 units in here is the same and they don't have plenums.
And my wife is none too pleased.
Any constructive thoughts? Any "tightening up" of the structure shouldn't figure in. Its just like a common boiler change. They don't understand the mechanics of heat loss, heat gain and the movement of moisture in Florida.
Is it true (like I was told) that in Florida, cold flows through the walls to get to the heat? Same with the moisture?