Setting the thermostat lower to cool faster
A fixed-speed AC cools at exactly one rate; setting 16°C instead of 23°C does not speed it up, it just removes the finish line. The unit runs flat out for hours past the comfortable point, wasting electricity and wear. Set the temperature you actually want and let the system cycle.
Washing filters but never the coil or blower
Filters catch the coarse dust; the fine shamal fraction sails through and mats onto the wet coil and blower wheel, where a household rinse cannot reach. If airflow stays weak and bills keep climbing despite clean filters, the machinery behind them is the problem, and it needs a chemical wash.
Closing vents in unused rooms to save energy
On a ducted system, closed supply vents raise static pressure in the ductwork rather than saving money: airflow across the coil drops, icing risk rises, and the blower strains. If a room genuinely never needs cooling, the right answer is a damper adjustment at the unit or a zoning setup, not a shut grille.