Air Conditioning Adelaide | Solar Power Systems

For many Adelaide homeowners, air conditioning and solar power are a natural match. Our summers are hot, dry, and often prolonged, which is exactly when a solar power system generates the most electricity.

If you already have a rooftop solar power system, or you’re considering installing a system, understanding how your air conditioner interacts with solar generation can help you reduce running costs, lower grid reliance, and maximise the return on your investment.

Why a Solar Power System and Air Conditioning work so well together

Adelaide experiences long, hot summers, with average maximum temperatures around 29°C in January and regular heatwaves exceeding 40°C. At the same time, South Australia enjoys some of the highest levels of solar exposure in the country, averaging around 4.8–5.0 kWh (kilowatt hours) per square metre per day. This coincidence is important.

Air conditioners typically work hardest during the middle of the day, when:

• Outdoor temperatures peak
• Cooling demand increases
• A solar power system produces the most electricity

This alignment means that a well-sized solar power system can offset a significant portion of your daytime air conditioning load, and in some cases, all of it.

How much power does an Air Conditioner use?

Understanding consumption is key to understanding savings, and typical “rule-of-thumb” running costs and energy usage in Australian homes are:

• Split system (single room):
  • 2.5–3.5 kW cooling capacity
  • Uses approx. 0.6–1.2 kW per hour
• Large split system (living area):
  • 5–7 kW cooling capacity
  • Uses approx. 1.5–2.5 kW per hour
• Ducted reverse cycle system (whole home):
  • Can draw 3–6 kW or more when running

If you run a 5 kW ducted system for 6 hours on a hot day, that could equate to 18–30 kWh of electricity consumption. With South Australian residential electricity rates for typical retail usage tariffs (including supply chain charges) ranging between 35–45 cents per kWh, that’s in the range of:

• $6.30–$13.50 per day
• $190–$400+ per month during peak summer

It is important to note that results will vary depending on your situation, but a solar power system changes the equation.

What can a typical Solar Power System cover?

The average residential solar system in South Australia is now approximately 6.6 kW, paired with a 5 kW inverter. In Adelaide, a 6.6 kW system typically generates:

• Around 24–28 kWh per day on average across the year
• 35+ kWh per day during peak summer conditions

That means:

• A solar system can fully cover daytime operation of a large split system
• It can offset a significant portion of ducted air conditioning usage
• Excess solar can power appliances, hot water, pool pumps, and more

South Australia has one of the highest adoptions of rooftop solar in the country, with more than 40% of homes having a system installed. In many suburbs, it’s closer to one in two homes.

The financial benefits of running Air Conditioning on Solar

1. Reduced Daytime Grid Usage

Every kilowatt-hour your solar power system supplies directly to your air conditioner is a kilowatt-hour you don’t buy from the grid.

As an example, if you offset 20 kWh per day during summer at 40c per kWh:

• That’s approximately $8 per day saved*
• Over a 90-day cooling season, that’s a saving of approximately $720 in electricity costs*

*Please note that any actual savings will vary depending on system size, your usage habits, export vs. self-consumption, and the electricity tariff structure. However, the principle remains: self-consumed solar energy is significantly more valuable than exported energy.

2. Avoiding Low Feed-In Tariffs

In South Australia, solar feed-in tariffs average approximately 5–10 cents per kWh, with some tiered plans offering slightly higher rates for the first few kWh exported each day, depending on your retailer. Compare that to buying electricity at approximately 35–45 cents per kWh.

Using your solar power system to operate your air conditioner can effectively avoid paying approximately 35–45 cents per kWh*, instead of earning approximately  5–10 cents per kWh* by exporting it on many plans. This difference significantly enhances your return on investment.

*Please note that any actual savings will vary depending on system size, your usage habits, export vs. self-consumption, and the electricity tariff structure.

3. Smoothing Peak Demand Costs

If you’re on a time-of-use tariff, peak rates often apply in the late afternoon and early evening. Pre-cooling your home during strong solar generation hours (for example, 11am–3pm) can reduce the need to run your system during expensive peak periods. For homes with ducted reverse cycle systems, this strategy can noticeably reduce summer bills.

Efficient year-round comfort with Solar and Reverse Cycle Air Conditioning

Modern reverse cycle air conditioners are highly efficient, with most systems generally delivering 3-4 units of heating or cooling for every 1 unit of electricity consumed (Coefficient of Performance or “COP” of 3-4+).

When powered by solar, that efficiency compounds the savings. In winter, Adelaide’s cool but still sunny days also allow a solar power system to offset daytime heating loads, particularly with ducted or multi-head split systems.

Practical tips for maximising Solar-Air Conditioning savings

If you already have solar:

• Run high-demand cooling during peak solar hours
• Pre-cool the home before peak tariff periods
• Use zoning (for ducted systems) to reduce unnecessary load
• Maintain filters and system efficiency
• Set realistic temperature settings (24–26°C in summer is typically optimal)

If you’re installing both solar and air conditioning:

• Size the solar system with cooling load in mind
• Consider future electrification (EV charging, hot water, etc.)
• Ensure your switchboard and inverter capacity are appropriate

Bringing it all together

Air conditioning is often one of the largest electricity expenses in South Australian homes. But when paired with a properly sized solar power system, it can become one of the smartest ways to use the power you generate.

Whether you already have solar or are considering installation, understanding how your cooling system interacts with solar generation allows you to:

• Reduce running costs
• Maximise self-consumption
• Improve return on investment
• Maintain comfortable indoor temperatures through Adelaide’s toughest heatwaves

At Glow, we regularly work with homeowners who are integrating efficient reverse cycle air conditioning systems into solar-powered homes. If you’re considering upgrading your air conditioning or planning for a new solar installation, choosing the right system and using it effectively can bring long-term benefits to your energy bills and comfort. Call us today!