What drives the bill
Two things matter: wattage (we estimate from each model's amp draw at 120V) and duty cycle — a right-sized unit in a sealed space might run 8–10 hours a day, while an undersized one in a damp Gulf Coast crawl space can run 24/7. That is why sizing correctly saves money twice: a cheaper unit that runs constantly often costs more per year than a bigger, more efficient one that cycles. Energy Star models (most of the AprilAire line, the AlorAir HD55/HD90) stretch each kWh further.