9.9kW Solar System Costs, Output, Returns

9.9kW Solar System Overview

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A 9.9kW solar system is practically identical in size to the 10kW solar system. Like the 10kW solar system, this is a significantly larger solar system than the average residential installation. We most commonly install these systems for residential clients with large homes (and big bills!) or small commercial/industrial properties, such as an industrial shed.

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Just like a 10kW solar system, a 9.9kW solar system will typically be paired with an 8kW (or bigger) solar inverter. This means that export limiting is usually required if your property is single phase, and might even be required for three phase supply depending on the area you’re in. Export limiting is simply the distributor (or DNSP, ie. the company that operates the electricity network) limiting the amount of solar energy back to the grid.

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You can expect to drastically decrease your bills with something as large as a 9.9kW solar system. Your exact savings will be dependent on how much of your solar energy you’re able to self-consume. This is also why we don’t recommend getting a system that is too large as the solar savings from exporting or feeding-in energy to the grid are not what they used to be.

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How Much Will a 9.9kW Solar System Generate?

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The savings potential from a 9.9kW solar system will vary significantly depending on where you’re located in Australia, if you have any shading, the pitch of the roof, orientation of the panels, and if export limiting is required.

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A ‘back of the envelope’ estimate for a 9.9kW solar system installed on an entirely north facing, unshaded, 21 degree pitched roof in Northern NSW or South-East QLD would generate on average approx 13,650kWh of solar energy a year.

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How Much Will a 9.9kW Solar System Save Me off My Energy Bill?

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If we use the above (ideal conditions) estimate, we can get a rough idea. Importantly, this estimate is for a ‘perfect’ installation and also assumes that you’ll be self-consuming all of your generated solar energy, instead of exporting it to the grid.

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Assuming a consumption tariff (electricity tariff) of $0.35, you’d save up to $4,778 a year (or just under $1200 a quarter) based on self-consuming all of the 13,650kWh you generate.

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What Actually Is a 9.9kW Solar System?

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As is the norm in the industry, the number quoted is not your solar inverter size but rather the amount of PV (solar panels) connected to it.

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To calculate your system size, you just multiply the number of panels by their rated power.

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For example, if you were using…

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…410W panels - 24x panels would equate to a 9.84kW system size

…420W panels - 24x panels would equate to a 10.08kW system size

…475W panels - 22x panels would equate to a 9.98kW system size

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If it helps, the formula is:  [Panel power (kW) each] x [Number of panels].

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So My Solar System Is Close to but Not Exactly 9.9kw Total?

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It’s unlikely that you’ll be able to get a ‘perfect 9.9kW’ system. Most of the time the total system power will be close to that number but not exact due to the power class of the panels we currently offer. We also tend to round to the nearest whole number for ease of comparison - in this case that’d be a 10kW solar system.

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Typically you’d be using an 8kW or 8.2kW inverter with a 9.9kW solar system. Given this, you’ll usually have some ‘headroom’ for extra panels as we’re allowed to connect up to 1.33x inverter output, which would equate to 10.64kW or 10.91kW respectively.

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If you have the roof space and the budget, we’d certainly recommend taking advantage of this rule and the extra government STC incentive and installing an extra 1-2 panels.

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Is a 9.9kw Solar System Right for Me?

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As we always say, it depends. It’s really difficult for us to say without conducting a proper assessment of your energy consumption habits, bills, and property.

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Just like a 10kW solar system, a 9.9kW solar system will typically require a fair amount of roof space or a small industrial building for installation. If you’ve got a larger home and big energy bills, or a small commercial premises, a 9.9kW or larger solar system may be what you need to start getting some energy bill relief.