Is a 6.6 kW solar system the right size for a Melbourne home?

Is 6.6 kW a good solar size in Melbourne?

For many smaller and medium-use homes, 6.6 kW can be a sensible residential solar size. It is especially common where a 5 kW inverter is appropriate and the household does not expect a major increase in electricity demand.

It can be too small for a highly electrified home, regular EV charging, a pool, large daytime loads or a household planning substantial battery storage. A larger array can also make sense when roof space is available and future electricity use is expected to rise.

What does “6.6 kW” actually mean?

The 6.6 kW figure normally refers to the total rated DC capacity of the solar panels. It does not mean the home will continuously receive 6.6 kW whenever the sun is out.

A common configuration is about 6.6 kW of panels paired with a 5 kW inverter. Solar Victoria explains that panel arrays are often oversized by up to about 33 per cent relative to inverter capacity. This is one reason the 6.6 kW array and 5 kW inverter combination became common.

How much electricity can 6.6 kW generate in Melbourne?

The Australian Government publishes a typical Melbourne average of about 3.6 kWh of electricity per day for each 1 kW of solar panels, averaged across a year. Using that city-level reference, a 6.6 kW array works out to about 23.8 kWh per day, or roughly 8,700 kWh per year.

That is a modelling reference, not a promise. Sustainability Victoria's orientation examples show why output can vary materially. Scaling its Melbourne examples to 6.6 kW gives an indicative spread of roughly 6,800 to 8,900 kWh a year from south-facing to north-facing arrays before allowing for the specific property's shade and equipment.

Summer output can be much higher than winter output. Solar Victoria notes that Victorian systems can produce more than twice as much in December as in July.

How much roof space does a 6.6 kW system need?

The Australian Government says a common 6.6 kW residential system may require about 29 to 32 square metres of sunny roof area, depending on panel wattage and dimensions.

Usable roof area matters more than total roof area. Shading, vents, roof geometry, access requirements and panel orientation can reduce the space available for a practical layout.

What sort of household may suit 6.6 kW?

A 6.6 kW array can be a reasonable candidate where household use is moderate, there is useful daytime consumption and future electric loads are limited. It can also suit a home that values a straightforward system and has constrained roof area.

Do not size from bedrooms alone. Two four-person households can need very different systems if one charges an EV and heats with electricity while the other uses little electricity during the day.

When is a larger solar array better?

Consider modelling 8 kW, 10 kW or a larger residential array when you expect more electricity use from EV charging, heat-pump hot water, electric heating and cooling, a pool, home working or future battery charging.

A larger array can also improve winter energy production because there is more panel capacity available during lower-sun periods. The trade-off is that additional summer generation may be exported or curtailed if the home cannot use it and the network limits exports.

Read how Victorian export limits affect larger systems ↗

Is 6.6 kW enough if you want a battery or EV?

Sometimes, but the battery and EV can change the answer. A battery needs enough available energy to recharge regularly. An EV can add a large flexible electrical load. If the household is likely to use both, modelling a larger array can be sensible even if current household consumption is modest.

Battery capacity in kWh and battery or inverter output in kW also need to be considered separately. A large battery attached to an undersized solar array may rely more heavily on grid charging, especially in winter.

See the battery sizing guide ↗

Does the Victorian Midday Power Saver make 6.6 kW less useful?

Not automatically. Since 1 October 2026, eligible households can opt into the Midday Power Saver and receive up to 24 kWh of no-cost grid electricity between 11 am and 2 pm each day. That can make flexible loads such as EV charging or battery charging cheaper during the window.

Solar still offsets electricity outside the free window and can reduce grid imports without requiring you to move every load into three hours. The Midday Power Saver also has higher priced periods outside the free window, so the right comparison is the whole electricity plan rather than the value of the midday period alone.

Read the Midday Power Saver solar and battery guide ↗