Buying a Home with Solar Panels? Here’s What You Need To Know

With millions of homes across Australia now powered by solar, there’s a good chance your new home will have solar panels on the roof.

A lot of research can go into buying the right sized solar system for a home, so it is important you get up to speed with how your solar system works to help you minimise your power bills.

How Big Is the Solar System?

First things first, check the documents that came with the solar system to see what size system you have.

The size of the system is the rating of each panel multiplied by the number of panels you have, for example, if you have 10 x 300W panels, then you have a 3kW system.

You will also have an inverter in the system. This converts DC power to AC so that it can be used in the home. Typcailly the inverter will be the same size as the panel array, or slightly smaller. For example, it is common to have a 6kW solar system with a 5kW inverter.

How Much Power Will the System Produce?

The output of a solar system will depend on where in Australia you live, the direction of your roof, the angle of your panels, as well as whether you have any shade affecting the panels.

Let’s start with where you are in Australia. Different cities across the country get different amounts of sunshine. You can multiply your system size to these output guidelines from  the Clean Energy Council to help you estimate the output of your system as a daily average:

Adelaide: 4.2

Brisbane: 4.2

Canberra: 4.3

Darwin: 4.4

Melbourne: 3.6

Perth: 4.4

Sydney: 3.9

So, for example, if you have a 5kW system in Sydney it will output 19.5kWh (5 x 3.9) as a daily average. This figure is a good starting point, however in reality your system will output a lot more power in the summer compared to winter. Here is the output of a 5kW system in Sydney broken down by month:

Roof Direction

A solar power system facing North with no shade will output most of its power during the middle of the day, basically in a bell curve as the sun moves across the sky.

If your panels are installed West, this output will be pushed further into the afternoon. If the panels are installed on an Eastern roof, then your system will produce more power in the morning and less in the afternoon.

Tilt Angle

The other thing that can influence output is the angle at which the panels are installed. Installing panels on a flat roof increases output in summer and decreases it in winter, whereas tilted panels or panels installed on a pitched roof will output more power in winter compared to the average system and a bit less in summer.

Shade

The last thing to note is any potential impact from shade, whether that be from clouds, trees, surrounding building etc. Shade doesn’t turn the system off, however, the output can be reduced depending on how dark it gets. Here is an example of a 5kW solar system producing power on a cloudy afternoon:

An important point to note from this graph is that a solar system’s maximum-output will always be below the system’s rating. In this example, the 5kW system has produced a maximum output of 4.61 kW, which is actually quite high. It is typical to see a 5kW system to max out at around 4kW at any one time.

It needs to be the right time of the day and the right time of the year for the system to produce the maximum amount of power, and even then there are a number of efficiency losses that will result in the output being below the rating of the system. The inverter will typically have a 96-97% efficiency, plus things like temperature, and air quality all have a little impact.

So don’t worry if the system is outputting power at a little below its rating, this is completely normal and factored into our daily output figures in the graph above.

Understanding How Your Solar System Powers Your Home

The power from a solar system in Australia is fed into the home for you to use as it is being generated. If you don’t use the power immediately, it is fed out to the grid and you can get paid a feed-in tariff from your energy retailer. When you take over the account for your new house, make sure you call around to the energy retailers and get a good deal from an energy retailer that offers you low energy tariffs as well as a good feed-in tariff for any excess solar power that is sent out to the grid.

The more solar power you use in the home as it is generated, the better. This is because by using the solar power you are not buying power from the grid, which typically costs around 25-30 cents per kWh plus GST.

If your solar system comes with online monitoring, makes sure you get the login details so that you can track how much power your system is generating across the day. It is good to get a basic understanding of how much power your system generates in different weather conditions and at various times across the day.

Some older systems won’t have online monitoring, in which case you can look at the little display on the inverter to see how much power the system is producing. The tricky thing with older systems is that it can be hard to match the amount of electricity used in the home and how much of that is covered by the solar system.

Newer ‘smart solar’ systems come with consumption monitoring so that you can compare how much power you are using in the home to how much power your system is producing. If you decide to add panels to your system, we include consumption monitoring with your system so that both the old panels and the new ones are displayed in the online monitoring.

If you don’t plan on adding solar panels to your system, and you are struggling to understand the small display on an old inverter, the best option is to buy a solar monitor, such as the one from Solar Analytics. This can be installed by an electrician in your meter board and will give you a full overview of your solar system as well as how much power you are using in the home. More information about Solar Analytics is available here: Solar Analytics

Is Your System Too Small? It’s Easy to Add Panels to Your System

The solar industry has come a long way in recent years. Prices are much cheaper for new panels and there is still a good government rebate in place for the additional panels you add to an existing system.

Smart solar technology allows us to add panels to a system irrespective of how old the existing system is. If your system is really old and taking up too much roof space, we can also remove the existing system for you and install a new one. This is becoming more common now that we are using 370W panels as standard, it is a far cry from the 250W panels we were installing only a few years ago. It can make good sense to remove older panels to free up roof space for a more efficient system.

If you are unsure about the best way forward, please submit an enquiry through to the 1KOMMA5° Team and we can help with a few suggestions. We are getting a lot of enquiries at the moment for adding panels to an existing system or to replace an older system. It doesn’t take us long to work out the best options for your situation and to provide you with a ballpark price, and of course, we will do all of that for you without any sales pressure.

Is Your System Too Large? Battery Storage Will Help

If you are exporting a lot of solar power to the grid, a battery will store that excess solar power so you can use it at night.

Tesla Powerwall is the battery we recommend for most households. It has a capacity of 14kWh and backup functionality so that your house can have power during a blackout (not all batteries have this backup functionality).

To have enough power to run your home and charge your battery, we typically recommend having at least a 5kW solar system, and yes, we can help you add more panels to an existing system and install a battery, a lot of households are now doing this.

Our solar experts will help you find the right system for your home.

• The Best Solar Panels To Install In Australia in 2024

• The Price, Output and Payback Period of a 10kW Solar System In Sydney In 2024

• How much is a 5kW or 6.6kW Solar Panel System in Melbourne?

• How Much Do Solar Systems Cost In 2024 in Sydney?

• Is Solar Power Worth It To Help You Save Money In 2024?

• How Much Does It Cost To Replace A Solar Panel Or Solar System?

Get all the right information before installing a solar power system for your home.