How to "Fix" My Old AC Unit (Without Replacing It)
If your AC is over 10 years old and struggling to hit 72 degrees, it might not be "broken." It might just be exhausted. Before you call an HVAC salesman, try these "environment fixes":
Cool the Ducts: Your AC ducts usually run through the attic. If your attic is 140°F, your "cold" air is being heated before it even reaches your vents. A radiant barrier cools the duct environment by 30 degrees.
Fiberglass Top-Off: If you can see your floor joists, your insulation is too low. A $0.70/sq ft fiberglass top-off can give an old AC the "help" it needs to finally win the battle.
Shade and Space: Ensure your outside condenser unit is clear of weeds and debris. It needs to "breathe" to dump the heat it pulled from your house.