How Many Solar Panels Do I Need For My House?

How many solar panels do I need? This is probably the most recurrent question for first time solar system buyers we get when they enquire about solar panel installation with e-Solar. The answer has been changing over the years for a number of reasons. In this blog, we’ll help you understand how the number of solar panels needed is calculated and how you can determine what size system is sufficient for your needs.

How has solar system size requirements changed over the years?

Firstly, because the individual panel wattage or W/size has increased over the years. When I started working in the solar industry in 1987, 40 W was the biggest and just enough to power a few lights at night.

Nowadays, electricity consumption has drastically increased. Now the average is 440 W up to 580 W. The most common system size for the average is 6.6 KW so using the 440 W you would need 15. By the same token you would only need 11 x 580 W for the same solar system size.

Solar panel system size can be determined by your energy usage

The right solar system size for you can also depend on your household or business electricity bills. For example, in Western Australia, an electricity bill of about $300-400 can be easily tackled by a 6.6 KW system.

For those paying around $1000 a 10 KW would be more appropriate especially if coupled with batteries.

There are plenty of online calculators that can help you calculate the specific solar system size or number of panels needed for your house, however over the years we’ve found that for the majority of Perth households that the most common solar panel system sizes are 6.6 KW, 10 KW, 15 KW.

For households paying around $1000 per bill, a 10 KW solar system would be more appropriate especially if coupled with solar batteries to maximise the savings and reduce your electricity bill.

Solar panel system size can be determined by electricity company standards and state regulations

Solar system sizes also depend heavily on your local electricity company standards and if they can be met. In Western Australia, Synergy is the only electrical company so this won’t influence Perth households too much.

In Western Australia, a house with a Single-phase metre can only go up to 5 KW inverter which with panels only can have a maximum 6.6 KW of solar panels.

However, if batteries are added to the system you can have up to 11 KW of panels. 3 phase metres can have 3 x 5 KW per phase or a maximum inverter size of 15 KW for most households, but in certain suburbs, 20-30 KW inverters have been allowed.

Understanding your household’s electrical consumption to determine the right solar system size for your needs

To better understand your power requirements or how much solar power you need to power your house, the first step is to look at your electrical bill and check your average daily units (KW/h) consumption.

Ideally, you would want a system big enough to generate your average usage a more to ensure the system produces enough even when the sun is not at its strongest such as early mornings and early evenings.

Always think ahead when planning for a new solar panel system

However, if you have the budget to, going over the minimum solar system size is the smart thing to do, especially if you are looking to future proof yourself for the long run.

It will also allow you to be more flexible with your power usage and not always have to watch the time of day or season when you want to run your air con to cool and heat your house or other loads such as dishwashers, washing machines etc etc. Planning to purchase an electric vehicle? If you want to charge your EV at night, you’ll likely want to consider a battery.

To give you a better idea, a simple tumble dryer takes 4 KW to run. If your system has a 5 KW inverter maximum output at the peak sun hours of the day, to avoid buying electricity when you run out, you won’t be able to have anything else on besides your fridge. To avoid paying extra for electricity in this scenario, you’d either need to avoid the tumble dryer or get yourself a bigger solar system with a larger inverter capacity, let’s say at least 10 KW.

Why the number of solar panels your household requires will continue to evolve

As you can see, lifestyle plays a big part in answering questions like ‘how many solar panels do I need?’, ‘what size solar system do I need?, ‘how much solar power does my house need?’ and so on.

Historically households power requirements have grown exponentially despite appliances becoming more efficient over time, we just end up using them more and more. There was a time where air conditioners weren’t so common until a few years ago and for cooling, people used evaporative systems and gas for heating.

Solar panel system size vs the number of panels you need

Gas is slowly being phased out, aircons are becoming the preferred solution for both heating and cooling and some families have them always on. The above are just some examples to address the questions but to keep it simple 6.6 KW system is the most used in the market, regardless of the number of panels that make up that total energy output.

This is important because many people tend to confuse the number of panels with the total system size. The ruling factor should always be the system size and if more panels are needed to make up that total, then older and less efficient panels are being used.

Get a fast, tailored solar system quote from e-Solar!

These days, you can find a solar system that is suitable for all standard appliances commonly found in all houses like TVs, washing machines and dishwashers. Having some solar is always better than having none at all and the savings are without question.

If you’re ready to start saving with solar power, getting a fast free quote from the friendly team at e-Solar is a no-brainer. We’ve been providing Perth households with tailored solar systems for 21+ years. There’s no better team to trust with your solar installation. Get in contact with our friendly team by calling (08) 6363 5420 or sending an online enquiry.