Need to know
- Not sure where to begin? See our four steps to get started with solar.
- Want to find out fast which solar panels are the best? See the test summary from our previous tests of solar panels (for members only).
- Our solar panel database (free) will let you compare specifications of panels from major brands.
- Interested in a solar storage battery? See our solar battery guide for more on how they work and whether they might suit your home.
Solar panels are increasingly being installed by homeowners who are worried about rising electricity costs, and who want a system that both cuts their bills and produces greener energy. We explain what you need to know before installing a solar photovoltaic (PV) system on your roof.
Some materials such as silicon can be made to produce electricity when light falls on them. This is called the photovoltaic effect. Solar panels use this to convert energy from sunlight into direct current (DC) electrical energy.
An inverter unit then changes this into alternating current (AC) for your home's electrical circuits. Any excess energy can be fed back to the electricity grid or to your own battery storage system.
Types of solar panel
The main types of solar panels you'll see on homes are monocrystalline and multicrystalline panels (aka polycrystalline), but there are other types too. Here's a quick explanation of the main solar panel types on the market today.
According to SolarQuotes, these are the current price ranges for good quality solar panel systems.
- 5kW: $4000–8000
- 6.6kW: $5500–9000
- 10kW: $8000–13,000
Those prices include the usual rebates and incentives. Expect to pay the higher end of the range if you're going for top-quality components or if your home has unusual installation requirements.
CHOICE tip: Compare prices for whole systems, not just individual panels.
How many solar panels do you need?
The power output of your whole solar system matters more than the size or number of panels. The higher each panel's nominal power rating (and actual power output), the fewer panels you'll need (or the more power you'll generate).
If you have plenty of roof space, you might find it more economical to buy cheaper panels with lower efficiency and just use more of them. Most solar panels are about 1.6–2 square metres in area, but they vary in length, width and power output.
CHOICE tip: Fewer panels can mean a quicker installation.
An example: You could use 20 x 320W panels, with each panel about 1.7m2 in area, for an array of 6.6kW and 33.7m2 total area. But you could go for a higher power panel from the same range, such as a 345W panel, and get a 6.9kW system that takes up the same area (though the panels might cost a little more).
Alternatively, you could make a 6.6kW system using 15 x 440W panels of 2.21m2 each, and it would also take up roughly the same area.
To size your solar panel system you need to work out how much electricity you use and when you use it.
As a guide, a typical home uses 20kWh of energy a day. A 5kW solar system would meet most of the daytime power needs of such a home.
However, these days solar panels are relatively cheap, so it usually makes sense to put on the biggest system that your roof can take and that you can afford. The excess electricity can go back into the grid and earn you some money via feed-in tariffs, or charge a home storage battery. 6.6kW is a common size for new systems, but bigger systems (9 to 10kW or more) are also being purchased. The bigger systems often include a battery.
Owning an electric vehicle (or planning to own one in the future) is another reason to consider upsizing the solar panel system, to ensure you've got plenty of cheap solar power to charge the car.
Estimate my solar system
Find out how much a solar system might cost you and what you'll save
It takes anywhere from two to seven years for a solar system to pay for itself – after that is when you can start counting the savings.
Payback times vary depending on where you live in Australia. The infographic below shows averages for capital cities.
Your home solar panel system has several benefits for the environment.
Power stations fuelled by coal and gas produce a lot of air pollution, in the form of particulate matter, carbon dioxide, methane and more. These have a direct impact on the climate and on personal health. Solar panels don't generate any such pollution.
There is some pollution generated during the manufacture of solar panels (as with all manufactured items), such as greenhouse gases and run-off chemicals. This is not to be ignored, but in general the amount is very small compared to the pollution produced by coal-fired power. There are also concerns about used and broken solar panels ending up in landfill at the end of their life, resulting in wastage of useful materials and possibly heavy metal contamination.
As the solar panel industry has grown, however, so has solar panel recycling, and there are now several solar panel recycling plants in Australia and around the world.
Reducing water usage
Australia is famously the driest continent on the planet, and traditional electricity generation in coal-fired power stations uses a huge amount of water (over 158 billion litres per year for New South Wales and Queensland alone). Even more water is consumed in mining and processing the coal itself. Solar panel manufacture also uses water, but once up on your roof and running, the panels don't use any water at all (except for an occasional cleaning, perhaps).
Reducing our dependence on fossil fuel
Much of Australia's electricity is still generated in coal-fired and gas-fired power stations. But while there are still significant deposits of coal and gas, those supplies won't last forever, and in any case it's becoming less economical to extract them. Gas companies are increasingly looking at fracking to extract more gas, a controversial process with potentially significant environmental risks of its own.
If your solar panel system is set up to export any unused power to the grid (as most are) then not only are you paid for that exported electricity, but it means there's more renewable energy in the system for others to use, and less need to generate electricity from coal or gas.
All in all, while they aren't entirely problem-free themselves, solar panels are a great option for reducing your home's environmental impact, as well as saving you money.
There are two main incentives that can help make your solar PV system more affordable: small-scale technology certificates (STCs) (the "solar rebate") and feed-in tariffs (FiTs). We explain these below. Apart from those incentives, other solar rebates and loans are available in some states and territories:
Victoria: Solar Homes Program
Northern Territory: Home and Business Battery Scheme
The battery schemes above are included because they can apply to a new solar PV system which includes a battery.
Rebate schemes change from time to time, so it's worth checking the federal government energy website to see what's available in your area.
Always check the terms and conditions for any rebate scheme carefully to make sure you're eligible, and what steps you need to take. For example, many schemes apply only to certain regions or postcodes, may have limited places available, or are only available to households below a certain income level, or you might need to have your proposed system approved by the scheme before it's installed.
A home storage battery lets you store the electricity generated by your solar panels to use at night or on a cloudy day.
You may want to consider a system that includes battery storage. The Tesla Powerwall is the best-known solar battery, but there are many other brands in the market. Generally, however, storage batteries don't make full economic sense yet for most homes.
You can, but there are more challenges to overcome. We outline your options below.
The electricity grid in Australia wasn't originally designed to cope with large numbers of homes exporting solar power into it. There are proposals for how to modernise the grid and manage it more effectively and fairly, and these include a possible surcharge – or "solar tax" – to owners of solar PV systems who want to sell their excess power to the grid.
What's this all about, and does it mean a storage battery becomes a better option?
- Assess what energy you currently use and the system capacity you need (and can afford).
- Check if your roof faces the right direction. Only north-facing panels will produce their full capacity.
- Make sure there are no trees, power lines or other structures shading your roof.
- Find out what local council approval is needed. Increasingly, local councils have staff on hand to help people make the best decisions on solar.
- Try to figure out your system's payback time.
- The inverter (which converts DC power from the panels into AC power for your home) is a key part of the system. See our guide to buying a solar inverter for all the details.
- If you're considering adding a battery, see our guide to solar storage batteries to understand the pros and cons.
- Get multiple quotes from installers to ensure you're getting a good deal, and make sure your installer is CEC-accredited (see below).
- Make sure your solar panels meet the required standards (see below).
- Check your solar panels' product and performance warranties – see below for what these are.
Installation, standards, warranties and maintenance
If you want to be eligible for small-scale technology certificates (STCs), your system must be installed by a CEC-accredited installer. The Clean Energy Council (CEC) is Australia's peak body representing the clean energy sector. It accredits both installers and systems that meet certain standards.
Look for a CEC-accredited company:
- that is a signatory to the CEC's code of conduct
- that has been in business for a while
- with an established track record
- with relevant experience
- that has specialist expertise
- that has a good reputation.
Retailers can also sign up to the CEC's voluntary code of conduct, which demonstrates a commitment to best-practice installation.
Solar panel specifications explained
When you look at the specs for a solar panel, you'll see a lot of numbers and terminology that you might not understand. Here are the basics.
PHOTO: CSIRO Energy Centre