Building 101: Everything you need to know about installing solar

If you’re renovating your home, building your first home or just looking to cut your electricity bills down, installing solar is something you should seriously consider. After all Australia has the highest solar generating potential of any continent. Unfortunately, installing solar can seem confusing and overwhelming: after all, what makes those solar panels better than these ones? And what does all the different jargon mean?

Use our handy guide to determine everything from which system suits your home to understanding the world of solar rebates. Here’s the good news though: it’s really easy to get started on the solar journey once you know even just a little.

The basics of solar

If you’re looking to get solar, then what you’re considering doing is installing a solar system (otherwise known as a photovoltaic or PV system) which absorbs energy generated by the sun. Solar panels supply power to a home during the day, alongside traditional ‘grid’ power that provides extra electricity when required on low sunlight days, at night, and at times of high power usage.

A typical solar system consists of solar panels and an inverter. There are two main types of inverters: a string inverter (which is installed on a wall with all solar panels connected), and microinverters (which are attached to the back of each solar panel). Inverters are the heart of a solar system, as they convert the electricity generated by panels into 240V AC power suitable for household use. 

There are three main types of solar panels: monocrystalline, polycrystalline and thin film. Monocrystalline panels are made from sliced up from larger silicon crystals to give them a uniform blue or black colour. This type of solar panel offers the higher efficiency. One drawback however is their curved edges, which lead to wasted space when multiple cells are combined to create a solar panel. So although they’re more efficient individually than polycrystalline, in a panel layout they’re only slightly more so. This style may suit your home more if the panels won’t be grouped together. Polycrystalline panels are created by pouring silicon into models rather than by cutting from crystal. This process leads to perfectly square solar cells, but they’re less pure than monocrystalline cells. While polycrystalline is less energy efficient than monocrystalline, they can be tightly spaced together on panels, so they end up only slightly less efficient than monocrystalline when in panel layout. Thin film panels are not made from silicon crystals but by spraying a layer of silicon onto a surface. Although thin film cells are cheap to produce, they’re heavier and far less efficient than monocrystalline or polycrystalline cells.

Since monocrystalline and polycrystalline solar panels are today so similar in terms of benefits, your choice might ultimately come down to personal preference and appearance. Monocrystalline solar panels are sleek and uniformly coloured and they have larger gaps between panels thanks to their curved design. On the other hand, polycrystalline panels tend to be colourful with smaller gaps between the cells and therefore have less wasted space.

An optional additional component of a solar system is a battery. A battery captures any unused solar power generated during the day for later use at night and on low-sunlight days. In instances where a solar-powered home does not have a battery, any excess power generated by the panels will be fed back into the grid (i.e. the network that carries electricity from power stations across the country). Australian households are generally compensated for this power in the form of a ‘feed-in tariff’, which is basically a small credit from their electricity retailer, in return for each kilowatt-hour (kWh) fed back into the grid.

Which system is right for me?

To determine what size solar system is most appropriate for your home, you first need to measure your electricity usage. You also need to consider how much (unshaded) space is available for panels, and how much energy you expect to use in the future. Some people may not need a battery, while others might due to the fact that they plan to get an electric vehicle one day, etc. We recommend sitting down with your household to discuss the future wants and needs of everyone, and then discussing these with the companies you contact about installing solar. They may be able to provide specialised advise for your situation.

A good rule of thumb is that you should size your system so that at least 50% of all your electricity needs are accounted for, so size up or down according to your needs. An easy way to do this is to take your most recent electricity bill, then divide your total daily consumption by four. For example a household using 20 kWh or more per day is likely to look at purchasing a 5 kW system or larger.

For most households a solar system of approximately 6.6 kW is a suitable size in Australia, but if you want larger benefits or to go all-electric with battery storage you may be better installing larger system options between 7-10 kW and beyond. If you can’t afford or don’t have the space to install a 6.6 kW system, a smaller 3-5 kW system can still be beneficial. A bonus of this option is that it will pay for itself much more quickly.

The size of your inverter will depend on the solar array, but a 5 kW inverter is usually recommended for a 6.6 kW system. 

A reputable solar consultant will be able to guide you through this entire process, taking into account your desired financial and environmental outcomes.

How much does solar cost?

The cost of solar can vary widely depending on what you’re looking for, but a good point to budget for is roughly $6,000-9,000. 3 kW systems are usually priced in the ballpark of $4,500–6,000, while 5 kW systems will put you back between $6,000-8,500 depending on what add-ons you get. Larger 10 kW solar systems are usually quoted as costing anything from $11,000–15,000+.

This covers the cost of the solar panels, the ‘mounting system’, installation, and the ‘balance of system’. The mountain system secures your solar panels to your roof and is therefore an essential element your solar panel system. The balance of system (or BOS) includes components like wires, cables, isolators, breakers, switches, and your inverter. The inverter could account for as much as 50% of the total cost of your system. Finally, installation or manual labour, which has to be carried out by a licensed electrician, is another component of the overall cost. 

While this is a lot of money at the beginning, note that most solar systems will have a typical payback period of approximately five years depending on your current energy costs and usage.

This is the price after discounts generated by the federal government’s Small-scale Renewable Energy Scheme (often referred to as the STC program) – a financial incentive for households and businesses to install eligible renewable energy systems. (You might have heard this referred to as the ‘solar rebate’, although that’s not its official title.) This scheme currently offers consumers a discount of around $585 per kW installed, but keep in mind most advertised prices of solar equipment will already take this into account. Some states have additional schemes reducing system prices even further, such as Victoria which offers an additional $1,850 rebate for eligible consumers. 

Research is everything when it comes to solar, so look into reputable companies and products to ensure you’re investing in quality. If the price is too good to be true, it probably is!

The process of installing solar

installing solar panels
Installing solar panels is a quick and easy process

So now that you’ve decided on which solar system you want installed, and you’ve got the money to get it, how will your new solar panels be installed?

A professional installer will also be able to advise you on the best placement of your panels for maximum possible output. Generally speaking north-facing panels will produce the most electricity overall in Australia, but having some panels facing east or west will allow your system to produce power earlier in the morning or later into the afternoon, respectively. You’ll be able to talk to the installer prior to the actual installation to get a solid plan of where exactly the panels will be placed. You’ll also want to discuss the panel angles: these will change depending on your house design, but you want to ensure the angle is steep enough to allow the panels to remain reasonably clean (minimum 10° is a good starting place).

If you live in an area prone to cyclones or other extreme weather events like areas of Queensland, you might be required to have your panels installed in a specific way. For example, your solar panels’ mounting systems will need to be certified. Your installer should discuss this with you when deciding on which panels and mounting you want.

Before you start installing anything, it’s important to ensure that you are having your solar system installed by a Clean Energy Council (CEC) accredited professional. That is, if you want to claim the government rebate anyway (which we know you do!). Once engaged, your solar installer will take care of the purchasing and organising of your solar system components. Below we have included links where you can check to make sure you’re industry and warranty compliant the whole way through the process. Lead times are generally one to three months, with installation often able to be completed in one day.

The pros and cons of solar

Pros of Solar

  • You’ll save money on power bills over the long term, with solar panels generally paying for themselves in around five years. You’ll also find that that you can be compensated via feed-in tariffs for exporting excess energy back to the grid, so you can take that weekend away you’ve been thinking about!
  • You’ll feel good about yourself! Solar power is good for the environment as a renewable power source.
  • Energy independence: even if everyone else in the street loses power, you’ll be fine.
  • Can make your home more attractive to buyers when you go to sell it.
  • Low ongoing maintenance costs (you might have to get them cleaned once a year, which is usually a very affordable).

Cons of Solar

  • High upfront cost.
  • Amount of energy generated can be smaller during winter months (although most Australian’s find we get more than enough sun to power your home).
  • Can look ‘ugly’: if your solar panels are in a highly visible position, you may get some glare during particularly sunny parts of the day, and they may stand out against your current roofing options.
  • Can damage your roof

Selling your energy back to the grid

And as you’re assessing the cost of the solar system, take into account the possibility of selling your energy back to the grid. This means you can get a credit against the power you draw from the grid when your panels aren’t generating enough electricity to cover your needs. The rate at which excess power sent back to the grid is calculated by using the feed-in-tariff.

Feed-in-tariffs could be part of what makes solar panels worth it for you. Australia’s feed-in-tariff system is also known as the Solar Bonus Scheme or Solar Buy-back Scheme. Feed-in-tariffs are designed to encourage people to go solar by allowing them to sell excess electricity back to the grid. When your system generates excess power, it’s sent to the grid and in effect sold to it. You get a feed-in tariff in exchange for this energy. The feed-in tariff is expressed in kilowatt hour (kWh) and varies per state and retailer. So the higher the feed-in tariff, the more money you get when you send unused electricity back to the grid.

Feed-in tariffs differ by state or territory because the system is administered at the state/territory level. The state government could set rules about feed-in-tariff rates, size of eligible systems, and types of systems. Currently, only Victoria has set a minimum feed-in-tariff rate (providers can choose to use a time-varying rate instead) and other states and territories have mostly opted not to require a mandatory minimum rate. However, the NT has a buyback scheme through PowerWater and WA has two different programs through Western Power and Horizon Power. Regional Queensland customers are protected by a minimum tariff rate.

In addition to setting minimum feed-in tariff rates, the state/territory government could have limits on how big the system can be to be eligible. For example, a system exceeding 100 kW in Victoria is not eligible to sell its excess energy back to the grid. You might have different limits on size of systems depending on whether it’s a single or three-phase system.

What’s the difference between net and gross metering?

When it comes to solar, two types of metering systems exist in Australia: net and gross metering. Most new homes are on a net metering system and gross metering is no longer offered for new connections except in Darwin. However, the Darwin gross feed-in tariff scheme is similar to a net tariff, since the purchase rates are the same as the feed-in rates.

With a net metering system, the power generated by your solar system is directed to household use first. Only when you excess power does it get sent to the grid. With a gross metering system, all the electricity your system generates is sent to the grid and you’re paid for every kilowatt hour your system generates.

Other things you should know about solar

Let’s start with an important one: warranties. Most solar panels are covered under warranty for 25 years, and a decent system should last at least that long. Warranties should include a workmanship guarantee (5 years per the CEC Approved Solar Retailers Code of Conduct), and cover the panels (25 years performance and 10 years workmanship), inverter (minimum 5 years parts and labour) and framing (minimum 10 years). Warranties can change depending on the installer, but these are the ballparks you should be looking for.

If you want to increase the your street appeal, it’s important to ensure that your homes solar panels are as unobtrusive as they can be. Generally speaking, most installers will try to integrate them into your roof, carport, etc as seamlessly as possible. This may not be possible due to a number of reasons (the direction your house faces is a significant factor) but even in cases where they may be visible, don’t worry too much. If it’s really bugging you, you can always have your roof repainted to a darker colour, camouflaging the panels. Some architects are now designing homes in ways that showcase solar panels on purpose, so if you want to make a statement that’s also an option!

You shouldn’t be afraid of checking your installers either. You might find a little more peace of mind of you as the installer for their CEC accreditation number (which you can check here), if they offer a performance guarantee, if their products meet Australian standards (you can check that here) and if you can contact a recent customer/read some testimonials.

There are also some costs associated with maintaining your solar panels. An annual inspection of your rooftop solar system should cost around $150. Added to this is the cost of cleaning your solar panels, which might average at $10 to $20 per panel. For a system with 10 panels, the annual maintenance outlay might be $330 (for $18 per panel), and for a 36-panel system the cost could be $789.

Written: 9 August 2020

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