7kW Solar System Costs, Output, Returns

An overview of 7kW solar system costs, expected outputs, and projected returns to help you make an informed decision about the correct solar system size for your commercial or residential premises.

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7kW Solar System Overview

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A 7kW solar system is a tad larger than the ever-popular 6.6kW solar system fitted to so many households in Australia. We find that a 7kW solar system is not very commonly installed, as it requires an inverter larger than 5kW on most installations, and therefore is usually subject to export limiting by the distributor/DNSP if your property is single phase - and most residential properties are.

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Despite export limiting being often required, a 7kW solar system will produce more than enough electricity to have a serious impact on your bill. How much? See below and we’ll do some rough calculations.

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Like most solar systems 6.6kW or larger, there’s typically enough solar export during the shorter winter days from a 7kW solar system to adequately charge a battery if you decide to add one to your system.

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How Much Will a 7kW Solar System Generate?

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How much a 7kW solar system will generate will vary greatly depending on your location, whether you have shading, the roof pitch, and the orientation of the panels.

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As a rough estimate, a 7kW solar system installed on an entirely north facing, unshaded, 21 degree pitched roof in Northern NSW or South-East QLD would generate approx 9,650kWh of solar energy a year - on average.

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How Much Will a 7kW Solar System Save Me Off My Energy Bill?

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We can do a quick and simple solar savings calculation using the above ideal estimate. It’s really important to note that how much you’ll actually save is entirely dependent on how much of your solar energy you can consume (we call this self-consumption). The more you can consume your solar energy instead of exporting, the better.

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If you’re paying a consumption tariff (or electricity tariff) of $0.35 and you’re consuming all of your solar energy, you’d save up to $3,378 a year (or $844 a quarter) based on 9,650kWh of solar generation.

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What actually is a 7kW solar system?

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We apologise in advance for any confusion, but stick with us. When talking system size, it’s common to quote the actual amount of solar panels (PV power) connected to the inverter. So for a 7kW solar system, it’d usually be a 6kW system (or larger) inverter paired with 7kW of solar panels (PV power).

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If you’d like to know your exact system size, it’s straightforward to calculate - just multiply panel power by number of panels connected. For example, if you were using…

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…410W panels - 17x panels would equate to a 6.97kW system size

…420W panels - 17x panels would equate to a 7.14W system size

…475W panels - 15x panels would equate to a 7.13kW system size

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The formula is simple: [Panel power (kW) each] x [Number of panels].

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So my solar system is close to but not exactly 7kW total?

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Whilst you’d be technically correct if you said it was a 6.97kW or 7.14kW solar system, the industry tends to round off to the nearest whole number for ease of comparison.

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It’s important to note that most of the time we’d be using a 6kW Fronius inverter for a 7kW solar system. This means that you could actually have up to 7.98kW of PV (solar panels) connected without violating the 1.33x inverter output rule for claiming STCs. This would equate to an additional 2x panels from 17x to 19x panels to ‘max out’ the inverter if using a 420W power panel size, and we’d suggest doing this if your budget and roof space allows.

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Is a 7kW solar system right for me?

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As always, it’s very difficult to say without properly assessing your property’s attributes, energy bills, and consumption habits.

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Whilst a 7kW solar system will produce a fair amount of energy, we’d generally recommend trying to get closer to 8kW to properly max out a 6kW sized inverter - as long as your budget and roof space allows.