How to Save Money on Air Conditioning
You do not need to choose between comfort and a frightening electricity bill. The biggest savings usually come from using the right size aircon, setting the temperature sensibly, keeping the room sealed, and maintaining the unit properly.
This quick guide explains how to reduce aircon running costs in a South African home or office without making the room uncomfortable.
Short-form guide | 4 min read | Category: Product Help → Air Conditioning
Aircons use electricity, but they should not waste it. If your unit is correctly sized, well maintained, and used at a realistic temperature, it can cool or heat a room efficiently without running flat out all day.
In South Africa, this matters because electricity is billed per unit of energy used. Whether you are on a municipal account, Eskom direct supply, or prepaid electricity, every unnecessary hour of hard compressor runtime adds cost. The goal is to reduce wasted cooling, not to avoid using the aircon completely.
In cooling mode, aim for around 24°C to 26°C for everyday summer comfort. Setting the aircon to 18°C will not cool the room “better” in a useful way; it usually just makes the unit work harder for longer.
For bedrooms, cool the room before sleep and then use sleep mode, eco mode, or a timer. A moderate temperature is normally more comfortable overnight than an extreme cold setting.
An aircon can only work efficiently if the room can hold the cooled air. Close windows, exterior doors, and unnecessary internal doors before running the unit.
If a lounge opens into a passage, kitchen, stairwell, or large open-plan area, the aircon may be trying to cool more space than you think. That increases runtime and electricity use.
Sunlight through glass can add a lot of heat to a room. Close curtains or blinds during the hottest part of the day, especially in west-facing rooms that get strong afternoon sun.
Ceiling insulation also helps. It reduces heat entering through the roof in summer and helps keep warmth inside during winter. That means the aircon does not need to work as hard in either season.
The wrong size aircon is one of the most expensive mistakes. An undersized unit runs constantly and still struggles to cool the room. An oversized unit can short cycle, create draughts, waste electricity, and feel less comfortable.
Use the BTU Calculator before buying. As a rough starting point:
| Room size | Common starting aircon size |
|---|---|
| Up to 15 m² | 9,000 BTU |
| 16 to 25 m² | 12,000 BTU |
| 26 to 35 m² | 18,000 BTU |
| 36 to 50 m² | 24,000 BTU |
Adjust for afternoon sun, poor insulation, high ceilings, open-plan layouts, large windows, and how many people normally use the room.
Dirty filters restrict airflow. When airflow drops, the aircon works harder, comfort drops, and electricity use can increase.
For typical home use, clean filters every 4 to 6 weeks during active use. If the room is dusty, the unit runs daily, or the aircon is in a high-use office, check the filters more often.
A service helps the aircon run efficiently before summer or winter demand peaks. A technician can check coils, drains, refrigerant performance, electrical connections, airflow, and general condition.
Skipping maintenance often costs more later. A dirty coil, blocked drain, poor airflow, or struggling fan motor can turn a normal electricity bill into an avoidable expense.
Do not run the aircon longer than needed. Use timers, sleep mode, eco mode, or Wi-Fi scheduling where available.
A useful summer routine is:
Small habits compound quickly when an aircon is used every day.
A newer inverter aircon can be more efficient than an old fixed-speed unit, especially in a room used daily. But upgrading is not always the first step. Before replacing a unit, check whether the current one is correctly sized, clean, and working properly.
Replacement makes more sense when the unit is old, noisy, expensive to repair, poorly sized, or no longer cooling or heating effectively.
You can save money by setting the aircon to a moderate temperature, closing doors and windows, cleaning filters, using timers, and making sure the unit is correctly sized. The biggest waste usually comes from cooling an open room, using an extreme temperature setting, or running a dirty or undersized unit for too long. Efficient use matters as much as the model you buy.
Air conditioners can use a noticeable amount of electricity, but usage depends on the unit size, inverter technology, room conditions, set temperature, and runtime. A correctly sized inverter aircon used at 24°C to 26°C will usually be easier to manage than an old, dirty, undersized unit running at very low settings. The more the compressor has to work, the more electricity the system uses.
For summer cooling, set your aircon to around 24°C to 26°C for a good balance between comfort and efficiency. Lower settings force the unit to work harder and can increase running costs. For bedrooms, use sleep mode or a timer instead of running the aircon at a very cold setting all night.
Heating air conditioners can be cost-effective when they use inverter heat-pump technology and are correctly sized for the room. They move heat instead of creating it the way a basic electric resistance heater does. Running cost still depends on room insulation, outdoor temperature, set temperature, and how long the unit runs.
Yes, aircon size affects electricity cost because the wrong BTU rating can make the unit work inefficiently. An undersized aircon may run constantly without reaching temperature, while an oversized unit can short cycle and waste energy. Use the BTU Calculator before buying so the aircon matches the room properly.
You should not buy the cheapest aircon unless it is still the correct size, type, and efficiency level for the room. A cheap unit that is too small, noisy, inefficient, or expensive to install can cost more over time. Compare the full cost: unit price, installation, electricity use, servicing, warranty, and expected lifespan.
Related: Browse air conditioners | Use the BTU Calculator