I argue that because we have a home computer network, we need not only to keep it cool, but also dry. She doesn't buy it. You would think I'd know better than to step into this one, but I'll take a shot at it. You are right, but mainly because you live in Houston. When it's hot outside, you definitely want to have the air conditioning on, particularly if you have a modern-era PC with its superfast chips that run hot.
Extreme heat is a major enemy to PC components.
However, even when its cool, there's a danger that the humid air could cause condensation on the metal parts of a PC when you turn it off. Water on the internal components of a PC is even worse. Heaters also dry the air, so no need to try to run the AC when it's chilly. However, if the humidity level gets to the point where you feel physically uncomfortable in mild temperatures, it's probably best to close the windows and turn down the thermostat. Maybe Computing columnist Dwight Silverman can help.