Why is my electricity bill so high in summer?

In a Houston house the air conditioner is the biggest single load on the meter from May to September, so a high summer bill is mostly the AC by definition. The useful question is whether it is higher than it should be, and the comparison that matters is the same month last year, not last month.

If the bill has jumped with no change in the weather or the household, four things explain most cases. A refrigerant charge that has dropped, which makes the system run longer to do the same work. A condenser coil choked with debris, which does the same. Ductwork leaking cold air into the attic, which is extremely common in houses from the eighties and nineties around here. And a heat pump that has gone onto electric backup heat in winter, which shows up as a shocking cold-week bill rather than a summer one.

A technician can measure all four. A charge check, a coil inspection, a duct leakage test and a look at the heat pump's controls take an afternoon, and the results usually point at one thing. Replacing a working system to save on the bill only makes sense once those have been ruled out.