Cut Your Summer Aircon Running Costs in Perth

Air conditioning is usually the single biggest line on a Perth summer power bill. The good news is that most of the savings come from how you run the system, not from replacing it.

Why Perth summers hit the bill so hard

Perth gets long runs of days above 35 degrees, and the inland suburbs cop the worst of it. Homes in the foothills, the Swan Valley and out towards Ellenbrook can sit several degrees hotter than the coast on the same afternoon, and they stay hotter overnight because brick and concrete hold the heat.

That means your system is not running for an hour here and there. It is running for most of the afternoon and evening, so anything that makes it work harder gets multiplied across the whole season.

Set the thermostat higher than you think

This is the biggest single lever. Every degree you drop the setpoint adds roughly 5 to 10 percent to the running cost.

• 24 to 25 degrees is comfortable for most Perth homes in summer
• Setting it to 18 does not cool the room any faster. It just makes the system run longer before it stops
• Use the fan on auto rather than high, and let the unit manage itself
• Ceiling fans make 25 degrees feel like 22 for a tiny fraction of the power

Cool early rather than at the peak

Once a house is heat soaked, pulling it back down is expensive. Getting in front of the heat is cheaper than chasing it.

1. Close blinds and curtains on north and west facing windows before mid morning
2. Start the system earlier at a moderate setpoint instead of blasting it at 4pm
3. Open up in the evening once the outside temperature drops below inside
4. Keep external doors shut during the afternoon, especially in open plan living areas

Only cool the rooms you actually use

Cooling empty bedrooms all afternoon is wasted money. On ducted systems, zoning is the tool for this, and most homes are not using it well. Our guide to ducted zoning covers how to set it up properly, and if your zones are not responding correctly a ducted service will usually sort it.

On split systems the equivalent is simple: shut the doors to rooms you are not using so the unit is cooling a smaller space.

Keep the airflow clean

A blocked system uses more power to move less air. This is the cheapest maintenance there is.

• Wash the indoor filters every 4 weeks through summer, not once a year
• Keep the outdoor unit clear of plants, bins and rubbish, with at least half a metre of space around it
• Hose the outdoor coil down gently if it looks dusty or full of leaves
• Book a proper split system service or ducted service before the season starts

A maintenance plan keeps this on a schedule so it does not get forgotten in November when everyone else is booking.

Fix the small faults early

Systems rarely fail suddenly. They get gradually more expensive to run first.

If your unit is taking longer to cool than it used to, icing up, or short cycling on and off, it is burning extra power every day it stays that way. A health check or an aircon repair booking will find the cause. Low refrigerant is one common culprit, and it always means a leak, so read our honest take before agreeing to a re-gas.

When the unit itself is the problem

Sometimes the running cost is baked in. Old non inverter units run flat out or not at all, while modern inverters ramp up and down and use far less power holding a temperature. An undersized unit is just as bad, because it never reaches setpoint and runs continuously.

Use the aircon size calculator to check whether your system suits the room. If it is undersized or well past ten years old, browse the shop or look at ducted installation options before summer arrives.

The short version

Set 24 to 25 degrees, get ahead of the heat, cool only what you use, clean the filters monthly, and fix small faults before they become daily costs. If something already feels off, book a visit now rather than in the middle of a heatwave.