An air conditioner performs two entirely separate functions: it drops the temperature (Sensible Cooling), and it removes water from the air (Latent Cooling). If your house is sucking in humid Texas air through the attic, your AC is fighting a losing battle against water, not heat.
Why Humidity Overrides The Thermostat
Humans cool off by sweating. If the air in your house is 55% relative humidity, sweat cannot evaporate off your skin. As a result, 74°F feels sticky and miserable. You instinctively walk over and drop the thermostat to 70°F, forcing the AC to run an extra 2 hours, burning massive amounts of electricity just to squeeze the water out of the air.
The "Air Sealing" Fix
Over 40% of the humidity inside a typical DFW home entered passively through the attic. Moist outside air naturally seeps through unsealed top plates, bathroom fan housings, and recessed lights. By professionally air sealing the attic deck before blowing insulation, you sever the humidity link.
Once the house is sealed, the ambient humidity drops to 45%. Suddenly, setting the thermostat permanently at 74°F feels crisper and cooler than your old leaky house did at 70°F. Your HVAC runtime drops, and your bills crash.