How much does it cost to add more solar panels in Perth?

PSW vs The Rest

Adding more solar panels can be more challenging than perceived for a string-inverter type solar array, accounting for 90% of solar energy systems installed in Perth, Western Australia. Matching solar panels of similar characteristics is best, avoiding uninhibited electrical flow throughout the solar array.


Size matters

How big are your current solar panels? When considering a string-inverter-type scenario, the electrical characteristics of each connecting solar panel must be similar to each other to perform at their optimum.

Past installation standards

Your previous solar energy system may likely be installed to prior government standards. Due to solar panel subsidising (Small Technology Certificates – STCs), the new installation and the system it is a part of must meet the current local and national standards.

The cost of adding more solar panels becomes elevated when an existing system upgrade is required.


There are different sets of warranty obligations when adding more solar panels. Bear in mind this may affect the existing system warranty if not previously installed by Perth Solar Warehouse.

Subsidy qualification

Does the existing system qualify for the subsidy? The Small Technology Certificate (STC) subsidy is on solar panel quantity.

The existing system’s inverter must be on the current approved CEC list of inverters. Past approvals don’t qualify. The new solar panels must be on the current CEC list of approved solar panels.

Adding more solar panels: Cost per Watt range

Should the existing system qualify for the current period Small Technology Certificates (subsidy), adding more solar panels can often be broken down to a cost-per-watt format. Better assisting with the normalisation of residential solar energy system costs.

The cost to add more solar panels ranges from 50c to $1.50 per/Watt. Customers should always seek site-specific quotes for accuracy. We can assist.

Alternative options

Avoid the subsidy qualification. 

It’s an option, but specific standards must still be met as an energy generation supply.

As a guide, the cost to add solar panels with the subsidy applied often offsets the panel cost. The price is likely to be similar.

Remove the current system.

Go new. It’s the most popular method, and starting from 50c per/Watt, what should be the seemingly more expensive option can often cost less while improving user-system experience, performance and function

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