Same usage, higher bill — a few habits and neglected maintenance are usually to blame, and most of them are cheap to fix once you know what to look for.
Common Culprits
- Dirty filters and coils forcing the compressor to work harder for the same cooling output.
- Low refrigerant levels, which make the unit run longer to reach the set temperature.
- Doors or windows left open in the cooled room, letting conditioned air escape.
- Setting the thermostat far colder than needed.
- An outdoor unit blocked by direct sun or poor airflow.
The Setting That Quietly Costs the Most
Every degree below around 24–25°C makes the compressor work noticeably harder to maintain. Running at 24°C with the fan on a higher speed usually feels just as comfortable as 18°C, at a fraction of the running cost over a full season.
Shading the Outdoor Unit
An outdoor unit sitting in direct afternoon sun has to reject heat into air that’s already hot, which reduces efficiency. A simple shade or canopy that doesn’t block airflow around the unit can measurably improve performance without any repair needed.
Maintenance Pays for Itself
A yearly service that cleans the coils and checks refrigerant levels typically pays for itself in efficiency within a season. Filters, in particular, are worth cleaning every two to four weeks during heavy summer use — it’s the single cheapest thing you can do to keep running costs down.