Why are my ceilings measuring 85 degrees while the AC is running?

The 54-degree vent temp tells me your HVAC is actually pulling its weight, but your ceiling is acting like a massive 85-degree radiant heater that’s canceling out the cooling. In Florida, you relly want a minimum of **R-38 to R-60** insulation, wich is usally about 13 to 20 inches of blown-in fiberglass or cellulose. If you're seeing those high temps on the drywall, you likely have less than 4 or 5 inches up there, or it's settled so much that it's lost its R-value entirely. That 97-degree ceiling in the add-on is a huge red flag. If there's no cavity for insulation, the sun is just baking that roof deck and the heat is transferring directly into your living space. You’re basially fighting physics at that point. For those tight spots, sometimes the only fix is to fur out the ceiling and add rigid foam boards or have someone inject closed-cell spray foam if there's any gap at all. Without some kind of thermal break, that room will always be a furnace.

You also need to check your attic ventilation. If the air in the attic is trapped and hitting 130+ degrees, it’s going to soak through even decent insulation eventually. Make sure your soffit vents aren't blocked by old insulation and that you have working ridge vents or a powered attic fan. If the attic can't breathe, your house can't stay cool.

Since you’re in Pompano, humidity is the other killer. If you have air leaks around your light fixtures or top plates, that hot, wet attic air is being sucked into the house as the AC runs. Grab a few cans of spray foam and **air seal** those gaps before you blow in more insulation. It’ll make a massive difference in how hard that Trane unit has to work to keep the temp steady 70 you're looking for.

Spot on about that radiant heat. If your ceiling is hitting 87 degrees, you're basicly living under a giant electric blanket. One thing the previous poster didn't mention is the attic access hatch itself. Most people forget that it's usally just a thin piece of plywood or drywall. If you don't have an insulated cover or a foam box over that opening, you're essentially leaving a window open to a 130-degree furnace. It's a tiny area but it'll dump a surprising amount of heat right into your hallway.

Don't forget to check your windows too. I'm over in Boca and had the same issue untill I realized my old single-panes were basially magnifying the sun. If you aren't ready to swap 'em out, get some ceramic window tint or even just blackout curtains. It keeps that Florida sun from baking your floors while the attic's baking your ceiling. Every little bit helps when the AC's struggling like that.

Oh wow, those thermal imaging guns are so cool! I just joined because I'm obsessed with fixing up my old place too. That 97-degree ceiling sounds absolutely wild though. Since you're already up there checking things, has anyone ever tried those space-blanket looking radiant barriers? I've seen videos of people stapling them to the rafters and I'm dying to know if they actualy work or if they're just a gimmick!

Quick update—I threw up some blackout curtains like suggested and it definately helped with the sun coming trough the glass. However, that ceiling in the addition is still hitting 97 degrees and radiating heat like crazy. I'm planning to blow in more insulation this weekend. shold I aim for the full R-60 or is that too much for a small Florida home?