3kW Solar system: Prices, power and savings

Not so long ago, a 3kW solar system was a popular choice in Australia. It represented a convenient balance between a low-cost investment and energy production. A 3kW system can generate enough power to cover daytime electricity usage for a low to medium energy user.

In recent years, four factors have made larger systems more popular by comparison:

• Falling solar panel prices
• Greater efficiency of solar panels
• Solar batteries increasing popularity
• Future electricity use is likely to be higher

A 3kW solar system still has its advantages. They suit households with very low energy consumption and, with the improvement in solar panel efficiency, can now be installed on very small rooftops.

How many panels make up a 3kW system?

If you stick to buying quality solar panel brands, you’ll only need 7 panels to make up a 3kW solar system. Each panel takes an area of roughly 1.7m², so the system will take up around 12m².

* Seven 475W panels will make up a slightly larger 3.3kW system.

It's possible that eight 375W solar panels make up a 3kW system, but more like it will be seven panels between 430W - 475W.

Suitable properties for a 3kW system

A 3kW system takes up little roof area, making them a really good option for the following types of properties:

• Investment properties
• Apartments
• Small townhouses
• Holiday properties

A 3kW system is the ideal size to install on an investment property, be it a unit or small house. Solar panels add value to rental properties, as tenants are willing to spend more on rent in return for lower electricity bills.

As an owner, you can even claim a rebate in some states if you install a system on an investment property.

Alternatively, if you live in an apartment or small townhouse, a 3kW system may be just the right size for your roof.

Power produced by a 3kW system

If you are a low to moderate energy user with no plans to add a battery in the future, a 3kW solar system may be adequate to power your electricity needs. The amount of solar energy a 3kW solar system generates varies according to your location; in Sydney, it will produce, on average, 11.7 kWh per day while in Perth it will generate nearly 13.2 kWh per day.

3kW system output in major cities:

The table below shows the output of 3kW solar systems in major Australian cities:

Solar panel output varies by season

A 3kW solar system will generate more power in summer and less power in winter. It helps to consider these variances with your electricity usage for each season so that you can select the most suitable system size for year-round savings.

3kW Solar system prices

A good quality 3kW system typically costs anywhere between $3,500 – $5,500 to fully install. System prices vary according to location as the number of sunshine hours impacts the size of the solar panel rebate.

Prices also vary according to the quality of components you select and the company you choose to perform the solar installation.

Average 3kW system prices in  major cities:

The table below shows average prices for a 3kW solar system in major Australian cities:

Low cost 3kW systems

You may see prices for budget 3kW systems much lower than our average prices. You may even see prices for 5kW systems that match the prices we publish for 3kW units. Our prices reflect the cost of installing a good system that will last its 25-year useful life.

Savings and payback on 3kW solar systems

The payback period for 3kW systems varies according to your location, electricity usage habits and property specifics like your roof orientation. In some states like Western Australia, a 3kW system can payback within a 4 – 5 year period, while in Tasmania it’s more likely to take between 5 – 7 years to payback.

A system that lasts 25 years can deliver lifetime savings of up to $40,000. The savings amount varies according to how you use your solar power and how much electricity you consume.

The graphic below shows results from our calculator for a typical 3kW system in Perth:

Accurate 3kW system calculations

For an accurate indication of the payback and savings of a 3kW system at your property, enter your location, usage and rooftop details into our solar panel calculator and evaluate your results.

Will a 3kW system be big enough?

If you are wondering if a 3kW system is big enough to power a house, it may be that your electricity usage is very low, or you use very little power during daylight hours.

However, if you have any intention of installing a battery in the near future, or charging an electric vehicle with solar power, you should consider a larger system. A 3kW system will not be big enough to power an all-electric house with accompanying EVs.

Reasons to select a larger system

Years ago, the sensible approach was to select a system size that output enough to power your daylight electricity needs. Several developments in recent years give cause for you to consider a larger system:

• Future electrification
• Cost vs value of larger systems
• Ability to add a battery to your system, if not now then later

Price and payback difference for a larger system

If you are considering upgrading from a 3kW unit, you might consider a 5kW solar system. We can explain the benefit of buying a larger system by comparing the price per kW of the two systems, using Brisbane as an example:

The price you will pay per kilowatt:

• 3kW system = $1,338
• Additional 2kW = $641

Payback on the extra 2kW

If we assume that you receive a feed-in tariff of 7c, it will only take just under six years to payback the additional 2kWs, assuming that all of it is exported back to the grid. If you use some of the solar panel output from the additional 2kWs to power your electricity needs, the payback period will be even faster.

Battery with a 3kW system

Adding a solar battery will increase the price of a 3kW solar system significantly. The cost of the system will depend on the size of the battery.

A 3kW system with a 5 kWh battery will cost between $9,000 - $12,000

A 3kW system with an 8 kWh battery will cost between $12,000 - $15,000.

If you are considering adding a battery to a 3kW solar panel system, you need to consider whether or not your system will generate enough power to charge the battery.

Typically, a 3kW hybrid system is likely to be large enough if you consume less than 10 – 12 kWh per day.

Battery ready system

If you plan on buying a battery ready system and adding solar storage at a later date, we suggest you consider a larger system, either a 5kW or 6.6kW system.