How Solar Powered Air Conditioners Work + Benefits & Costs

With electricity prices continuing to rise across Australia, more and more people are turning to solar powered air conditioners to reduce their electricity consumption. As well as being a great source of renewable energy, solar power can help you cut costs along the way. Indeed, the Australian Energy Council estimates that 3.04 million Australian households and businesses had a rooftop solar system in 2021.

But how reliable is solar power for running your air conditioning? Do you need a solar battery? And how many solar panels do you need? These are just a few of the most common questions we get asked by customers looking to make the switch to solar powered air conditioners.

So, to help answer these and other common questions, we’ve pulled together this guide on everything you need to know about solar powered air conditioners.

What is a solar powered air conditioner and how does it work?

In the simplest terms, a solar powered air conditioner is one powered by solar generated electricity, rather than mains power electricity. Solar electricity is generated by solar panels, which convert energy from the sun into direct current (DC) electricity. An inverter then converts the DC electricity into alternating current (AC) electricity, so that it can be passed through a switchboard to be used by household appliances.

Broadly speaking, there are two ways to air condition your home using solar power:

Connect your existing, standard air conditioner to your household solar power system, in the same way you would any other appliance. This is the most common way to run air conditioning on solar power in Australia and is compatible with all existing air conditioning units.
Install a stand-alone solar powered air conditioner, with its own solar panels. In this instance, the air conditioner and its panels are entirely separate from any other solar panel system already in place. There are different types of stand-alone solar powered air conditioners, some of which run on DC or AC electricity only.

As the first option is the more common way to run air conditioning on solar power in Australia, this article will focus on how to power a regular air conditioning unit with solar.

When can you run AC on solar power?

Just like other household appliances, solar powered air conditioners will run off solar power whenever it is being produced. Then when solar power is not available, the air conditioner will switch to running on mains electricity. This typically means that your air conditioner will draw on solar power during the day and switch to running on grid electricity at night. The air conditioner may also revert to mains power on days when not enough solar power is generated—such as very cloudy days.

Because solar powered air conditioners are backed up by a connection to the grid, you don’t need to worry about your air conditioning not working when you need it to. However, if you want to minimise the amount of mains power it uses, it can be a good idea to install a battery to save surplus power, or change the way you use your air conditioner to make the most of the available solar energy. For example, setting the air conditioner to run an hour or two before you get home—while the sun is still shining—can help to reduce the amount of mains electricity you need to use at night.

It’s also a great idea to consider other changes you can make to minimise how long your air conditioner needs to run, and ensure your air conditioner is working efficiently to heat or cool your space.

What solar panel set-up do you need for solar powered air conditioners?

If you’ve already got other household appliances set up to run off solar power, you might be wondering whether you need additional panels to power your air conditioner. The good news is that no air conditioner specific system is required. You just need to make sure your solar system is the right size to meet your air conditioner’s power output (and other household energy requirements).

Numerous factors will determine what size solar power system you need. These include:

Your daily energy usage. Naturally, the more energy you consume, the bigger the system you’ll need. In Australia, the average solar unit size is approximately 9 kW – or enough to produce an average of 35 kWh per day. However, it’s important to select the right size system for your specific energy needs. You can find your average daily energy usage in kWh on previous power bills.
When you use most of your energy. This will influence the balance of solar and grid electricity needed to power your air conditioner. For example, if the majority of your energy consumption occurs at night, you may need to invest in a solar battery to store the surplus energy you produce during the day.
The size and orientation of your house. Both the amount of suitable roof space you have available, and the amount of sunlight it receives will influence the number of solar panels you need. For example, if your roof is partly shaded, you may need more solar panels to compensate for the ones in the shade. Similarly, if most of your available roof space is facing south rather than north (which is the optimal orientation for solar panels), you may need more panels.
Your local climate. This influences the amount of sunlight available. For instance, someone living in Melbourne, where there are fewer sunlight hours, is likely to need more solar panels than someone living in Perth.
How much mains power you want to save. The right size solar system will also be influenced by how much energy you want to save. For instance, if you want to be nearly entirely self-sufficient, you’ll need to invest in a larger solar system with a battery, whereas if you simply want to cover your daytime energy needs, a smaller system will meet your needs.

The best way to determine what solar set up is right for you is to speak with a solar retailer. This list can help you find a Clean Energy Council approved solar retailer near you.

Do you need a solar battery to run solar powered air conditioners?

Installing a battery alongside your solar system can further reduce your mains electricity usage (and power bills), by helping to increase the amount of time your air conditioner runs on solar power, as opposed to mains electricity.

With a battery installed, excess solar power produced during the day is stored in the battery for use at night or on cloudy days. Once this power is exhausted, the air conditioner will then revert to mains power.

It’s not essential to install a battery to power your air conditioner. However it can be a worthwhile investment if you live in an area that receives less sunlight—particularly in winter—or the majority of your air conditioner usage will be at night when solar power isn’t being generated.

It’s also important to bear in mind that solar batteries typically won’t cover your entire energy demand.

How much energy can you save by switching to a solar powered air conditioner?

The amount of energy you’ll save by switching to a solar powered air conditioner will depend on several factors, including:

The size of your solar set-up. The more power the system produces, the less you’ll rely on mains electricity to step in. Your savings will be greatest if you have a battery installed that allows you to draw on solar power at night.
How you use your air conditioner. You will save more energy if you use your air conditioner during the day while the solar system is producing energy, than if you use it at night when the air conditioner reverts to mains electricity.
How efficient your air conditioning unit is, and how well it is maintained.

How much do solar powered air conditioners cost?

While solar powered air conditioners will reduce your electricity bill, helping you to save money in the long-run, solar installation requires a relatively high upfront investment. Depending on the size of your system, it will likely take between 5 and 10 years for the cost to be recovered.

Across Australia, the average cost of a solar system without a battery, ranges from roughly $4,000 for a 3kW system, to $9,610 for a 10kW system. Roughly speaking, home solar batteries are then an additional $1,000 – $2,000 per kWh of storage capacity. On top of that will be the cost of the air conditioning unit itself, as well as the cost of regular air conditioner maintenance.

However, over time the majority of households recoup this initial investment through lower electricity bills. Additionally, if you have surplus energy that isn’t used or stored in a battery, you may receive a small feed-in-tariff of between 4 and 12 cents per kWh, when this is sent back to the grid, which can help to offset the initial start-up cost.

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