Guide to solar panels for your home

When choosing which solar panels to use, it is important to assess your individual needs. Image: Matt Harvey.

What are the most energy efficient solar panels to buy?

Solar panel technology is improving, and the newer systems are more efficient than those even a few years older. 

“In the past 10 years, the average efficiency has increased greatly from around 15 per cent to well over 20 per cent for good quality solar panel systems,” says McCarthy. 

“The highest efficiency Solar photovoltaic (PV) panels available today are Sunpower’s Maxeon AC panels. The company has consistently set efficiency records over the last decade and we’ve seen the proof over the many years we’ve been installing them on customers' rooftops.”  

“In fact, they are claimed to generate more power from the same roof than other solar panels. This could be up to 35 per cent more energy from the same space over the first 25 years, so they are the perfect choice for customers with limited roof space, or those who want the very best technology.”

How much do solar panels cost?

Depending on the type of solar panels used, the brand, how many panels are installed, the size of the home and eligibility status for a Victorian solar rebate, solar systems range in price from as little as $3000, to more than $25,000 for a large solar panel and battery system. 

“Remember that solar is a long-term investment, so it’s not worth prioritising a cheap price tag at the expense of good quality products and installation,” says McCarthy. “Your installer will work with you to design the right system for your needs and budget.”  

Are solar panels worth it?

For a decent quality 6.6kW system and installation for an average family home, the payback period will be 5 years or less.  

“Solar panels have continued to decline in price over time. At the same time, solar panel technology is improving,” says McCarthy.

“In the past 10 years, the price for a solar panel has plummeted while the average efficiency has increased greatly. Electricity bills have also risen by 100 to 150 per cent in that time, and we’re now seeing gas becoming increasingly costly too – so in almost all cases, solar panels are definitely worth it!” 
 

When installing solar panels, it is important to go with an accredited professional. Image: Matt Harvey. 

How are solar panels installed on the roof?

Always have solar panels installed by an experienced and accredited solar panel installer. They will take care of the full design and installation of your system. 

Solar panels are mounted on rail which is fixed to your roof and the panels are screwed securely to the mounting system. An electrical cable is then run from the solar panels to your inverter and into your switchboard. 

“Any good quality installer will take care when installing your solar panels, choosing the right mounting system to suit the roof material and type,” says McCarthy. “And if you have a tiled roof, accidents can happen no matter how careful the installer is, so it’s always a good idea to have some spare tiles on hand so they can replace a broken tile for you straight away.” 

How long do solar panels last?

Good quality solar panels will keep performing well up to 25 years and beyond, provided they’ve been installed well. 

Leading panels now come with a product warranty of anywhere between 15 and 25 years (this is different to a 25-year performance guarantee, so be sure to check carefully). 

“SunPower is arguably the world’s leading solar panel manufacturer and has just announced a product warranty of 40 years on its Maxeon range,” says McCarthy.  

“This shows how confident the top manufacturers are becoming in their product’s performance over time. However, a solar panel’s lifetime also depends on the quality of the installation workmanship, so make sure you select a quality installer with a good reputation,” he adds.

How many solar panels do I need?

The number of solar panels installed depends on how much electricity the home or business uses, as well as how much is likely to be used in the future. 

“There’s no point sizing a solar system to simply meet your current energy needs if you plan to grow your family or get an Electric Vehicle soon,” says McCarthy. 

“As an example, a 6.6kWh solar system – that’s about 16 to 18 solar panels with current panel efficacy being around 400 watts – is usually enough for the average family home. However, as a general rule, if you have room in your budget and on your roof, the more panels you get the better,” he adds.

The number of solar panels you need not only depends on how much solar energy you require today, but how much you'll need in the future. Image: Matt Harvey.

Can I run my home on solar power alone?

To run a home entirely on solar power, a battery is needed to store the energy generated by panels during the day for use overnight, according to McCarthy.

“You’ll also need to ensure your solar energy system is big enough to cover your energy needs and then some. So, during a string of overcast days, you’ll have enough electricity stored in your battery to get you through without drawing from the grid.”

While solar power systems automatically stop working when there’s a power blackout on the grid, many new solar battery storage systems also come equipped with a back-up option which can provide backup power during a power out. Before you invest in solar power in your home, check whether the battery has a back-up option.

What do I clean solar panels with?

A garden hose and long-handled brush can efficiently clean solar panels. However, only apply water to panels when the panels are cool, for example in the morning as the sun is coming up, or in the evening. 

If cold water is applied to a hot panel, there is a risk that the panel could crack.  Never walk across your panels when cleaning them – they might be strong, but the weight of the average sized person is still a lot for them to bear. 

Can I use solar panels on my roof to charge an Electric Vehicle (EV)? 

The short answer is: Yes.

“A solar panel system is a great option for EV owners,” says McCarthy.

“I’ve owned an EV for the last eight years and there’s nothing more satisfying than charging your car with power from the sun, particularly when fuel prices have risen so much over the last decade,” he adds.

Remember, you need to charge your EV when your panels are producing solar, otherwise you will still be charging your vehicle from grid electricity, even if you have solar panels installed. 

A smart EV charger for your home, such as one installed by RACV Solar, can be programmed to divert excess solar power to charge your EV during the day, rather than sending that electricity back to the grid where you will get little benefit.

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