How Much Solar Power Do I Need To Run My Home?

Let’s face it, Australia’s electrical power woes are well documented. In fact, with household utilities increasing by 20% on average in 2017 alone, I challenge you to tell me a person who hasn’t complained about the sky-high cost of their utility bills.

To put this into perspective, the average household electricity prices in Queensland (a little over 27 cents per kw at the time of writing) are:

  • 28% higher than Japan
  • 156% higher than Canada and a staggering…
  • 168% higher than the US.

It’s little wonder then that more and more Australian homeowners are considering turning to solar energy. With this in mind, one of the most frequent questions we get asked is “How much solar power do I really need for my home?” Let’s dive in and take a look closer look.

Solar energy – Explaining the basics

Typically, the relevant size of a solar power system is known by its Peak Volume (PV) amount. This is the amount of electricity your system is likely to produce on a gloriously sunny day. So, a 5kw system, for example, will produce roughly 5000w at peak sunshine. 1kw equals 1000 watts – Got it? Great!

So, if your system was made up of 250w panels you would need 20 x 250w panels in order to collectively generate 5000 watts or 5kw.

So, what can you expect to run with 1kw (1000 watts) of power?

Well, believe it or not, 1000w is sufficient to power:

  • 60 low energy bulbs
  • 2 x 32” plasma screen TV’s
  • 1 small pool pump, and around…
  • One half of a small A/C unit

While that seems pretty good, there’s a catch – I know, there always is!

A 1kw solar system will only give you 1000 watts of power for a few hours a day – Remember peak volume? So your 60 low energy bulbs, for example, will only be working for a short period of time.

So how do you overcome these peaks and troughs?

The answer…by connecting to the electricity grid. Okay, so it may seem counterintuitive to connect to the very thing you’re trying to escape from, but while the grid absorbs any excess energy you don’t use in your home (e.g, when the sun is strong and you aren’t running the A/C) it also works in reverse and can be used to top up your electrical needs when you’re using more power than your solar panels can output.

The question now is…how many solar panels do you need in order to offset your electricity usage?

Here’s how to work it out…

Step 1 – Look at your most recent utility bill and note the amount of KWH’s you’ve used in the previous four quarters. This gives you a better overall representation taking into account the seasons. Let’s imagine you use the national average of 5840 kwh’s per year.

Step 2 – Now divide your annual KWH output by 365 – This gives you a daily figure – For this example that’s 16kwh’s per day!

Step 3 – Now divide your daily figure by the average number of KW hours generated in your city. This will be something like…

  • 2 for Brisbane
  • 6 for Melbourne or
  • 9 for Sydney


Let’s take Brisbane for example as this is where our offices are. So that’s…

16kwh’s divided by 4.2 which gives us a final figure of 3.8

Therefore you would need a 3.8kw solar energy system to generate the same amount of electricity that you currently use.

So there you have it…That’s how you can quickly work out how much solar power you need to run your home.

However…there’s always a ‘but’ right? You need to consider that from an economic perspective, it mightn’t always be the optimal system size you need. So, here’s what we suggest…

Talk to an experienced company who can design a system to suit your exacting needs. This way, not only will you get good advice, but also you’ll get all your questions answered, leaving you with the ability to make a better-informed decision.

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