How to Cut Your Air Con Running Costs This Summer

Wollongong summers are no joke — the humidity makes it worse than the temperature alone. Your air con ends up running for weeks at a time, and the electricity bill reflects it. The good news is that a few simple changes can cut your cooling costs significantly without making your home any less comfortable.

These are the tips our technicians give every customer when we're on site. They're based on what actually works in real Illawarra homes.

1. Set the Temperature to 24–26°C, Not 18°C

Every degree lower you set your thermostat increases energy consumption by approximately 10%. Most people set the temperature way too cold — they come in from outside feeling hot and crank it down to 18°C, then get cold and grab a blanket. That's just wasted electricity.

24–26°C is comfortable for most people and uses significantly less power than 20°C. Give the room 20 minutes to cool down before deciding it's not cold enough.

2. Use the Timer to Pre-Cool Your Home

Running your air con before the heat peaks is more efficient than trying to cool a hot house. Set it to come on an hour before you get home, or before the afternoon heat builds up. A house at 28°C is much easier to cool than one at 35°C.

Most modern split systems have a timer function. If yours doesn't, or if you want to control it remotely, look at smart plugs or a system with Wi-Fi control — Daikin, Fujitsu and Mitsubishi all offer these.

3. Keep the Filters Clean

A dirty filter is like trying to breathe through a cloth — the unit has to work much harder to pull air through it. This increases electricity use and puts stress on the compressor. A clean filter can improve efficiency by 5–15%.

Most split system filters should be cleaned every 4–6 weeks during heavy use. It takes 5 minutes — slide out the filter, rinse it under a tap, let it dry, and slide it back in.

4. Use Ceiling Fans Alongside Your Air Con

A ceiling fan uses about as much electricity as a light bulb. When used with your air con, it circulates the cold air around the room much more effectively — allowing you to run the air con at a higher temperature setting for the same level of comfort.

This combination typically cuts air con runtime by 20–30%. Make sure your fan is set to run anti-clockwise in summer (pushing air down).

5. Block the Heat Before It Gets In

Your air con is fighting against every bit of heat entering the home. Close blinds and curtains on north and west-facing windows before the sun hits them. External awnings and shade sails are even more effective. Keep doors and windows closed while the system is running.

• Close west-facing blinds by early afternoon
• Use blockout curtains in bedrooms
• Seal gaps under doors and around windows
• Consider external roller blinds on windows that get direct afternoon sun

6. Service Your System Annually

An air conditioner that hasn't been serviced in a few years can be running at 20–30% below its rated efficiency. Dirty coils, low refrigerant and worn components all contribute. An annual service by a licensed technician restores the system to peak performance — and typically pays for itself in energy savings within one or two billing cycles.

7. Consider Upgrading an Old, Inefficient Unit

If your air con is more than 10 years old, the efficiency gains from a new inverter unit can be dramatic. Modern inverter split systems use up to 50% less electricity than non-inverter units from a decade ago. If your current unit is struggling, do the maths — a new unit may pay for itself in 3–4 years of energy savings.