Taking the time to calculate what size solar system you need is important. Get it wrong, and you could be hundreds of dollars out of pocket each quarter. So how do you work out what size solar system is right for your family?

Going back a few years ago, the average residential solar power system size was 6.6kW. Fast forward to 2021 and the average system size we install is now 10kW to13kW! But why?

Well, there are a few reasons including:

  • the amount of electricity we use has increased
  • the price of electricity has gone up, and
  • the solar feed-in tariff has gone down.

In terms of electricity consumption, the average Aussie family now consumes around 25kWh per day. Depending on your electricity retailer, this means your bill would be about $600 plus per quarter. If you’re among the Queenslanders who can’t survive without air con, you may find your bills go up in summer.

Families in larger homes with a pool and ducted cooling/heating might use 45kWh per day, sometimes even more. In this case, you’re probably forking out around $1,000 per quarter!

With these figures in mind, a 6.6kW solar power system simply won’t cut it. In fact, you can expect a bill every quarter!

The key to solar savings

When you invest in solar power for your home, the last thing you want is a quarterly electricity bill. How good would it be to see your bill in credit each quarter?

Despite the rise in electricity costs and the fall in feed-in tariffs, it’s possible to achieve quarterly credits. But it comes back to the size of the solar system.

The key is to design a solar system that produces more than enough energy to power your home. In the absence of a solar battery, the energy you don’t use is exported to the grid. When this happens, your electricity retailer pays you in credits. The credits offset your usage at night.

To wipe the electricity bills and future-proof homes, more and more Aussie families are installing larger solar power systems. In fact, according to the Australian Energy Council, the average solar system size has increased from 2.65kW in 2012, to more 8.86kW in December 2020!

Is a larger solar power system better?

When it comes to solar power, size matters. Calculating what size solar system you need depends largely on your power usage. Since household usage varies from family to family, solar requirements will also vary. There are many factors we consider when designing a solar system to meet your energy requirements. They include:

  • the size of your home
  • the location
  • the orientation
  • the number of people living in your home
  • heating and cooling (usage and type)
  • insulation
  • energy efficient appliances and lighting
  • lifestyle choices such as a pool/spa, and
  • future needs.

What if my energy needs change?

What if the amount of electricity you consume today is not the same in a few years’ time? It’s highly likely. Our energy needs have changed dramatically over the past 20 years.

Our World in Data shows the amount of electricity consumed per person in Australia has almost doubled over the last 50 years!

There are plenty of reasons your electricity usage might change over time.

  1. Installing a pool.
  2. Installing a home battery.
  3. Installing/upgrading air con units or ducted reverse cycle air conditioning.
  4. Purchasing and charging an electric car.
  5. Renovating and increasing the size of your home.
  6. Adding family members such as new bubs, or grandparents.

A 6.6kW solar system could be a big mistake

As we’ve discovered, if your household electricity usage is high, a 6.6kW solar system won’t wipe your bill.

If you can afford it, consider installing more solar panels now. In the long run, it’s much cheaper and easier than trying to increase your system size later.

Families with smaller solar systems will soon face an even bigger problem than the quarterly power bill. In the event a solar system doesn’t produce enough energy to power the home, then how can it charge a home battery?

When you install solar battery storage, the energy you don’t use to power your home is stored. This energy is then used at night, or when the sun isn’t shining. If your solar system isn’t producing enough energy to export to the grid, then it’s highly unlikely your system will produce enough energy to fill your battery.

If you have an empty battery, you’ll need to buy electricity from your retailer. And, in a few years’ time, who knows what the price will be!

Furthermore, by 2030, it’s estimated that more than half the population will drive an electric vehicle. It’s highly likely your next car will be an EV. It’s less than a decade away!

To charge the car, we’ll either need to buy electricity from our retailer, tap into the solar power, or use energy stored in our home battery. Regardless of the scenario, your household electricity usage will increase by 20% to 30%, based on charging your car twice a week.

Get your solar system size right. First time.

Your solar system should last around 20 to 25 years!  While we don’t have a crystal ball, we can predict that our electricity usage will most definitely change during that time.

Future-proof your home with a 10kW solar system. If you can fit 13kW of panels, and the budget allows it, then consider this option. If you have a three-phase home, then fill the roof with solar panels!

Need help calculating what size solar system you need? Get in touch today. We take the guess work out of solar and give you the tools to compare system sizes. The facts will help you make an educated decision that works for you.

Up next, get to know your meter box. Do you need a simple upgrade before you can install solar? Learn more here.