Southern Plumbing Plus

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$31,400 in annual savings with a 3.1 years payback

Key Results

About Southern Plumbing Plus

Southern Plumbing Plus is an independent supplier of plumbing, bathroom and kitchen products in the ACT, southern NSW and north-eastern Victoria regions.

Family-owned for more than 40 years, the company hires more than 100 employees throughout their six sites. Their head office, main warehouses and flagship showroom are in Fyshwick, ACT. This building complex holds around 50 employees, and is visited by thousands of clients annually.

The energy demand at this address is predominantly for heating and cooling needs, which is provided by multiple electric air conditioning systems. There is almost no energy consumption in the evening and night, which is usual for commercial buildings like offices and stores with nine-to-five operating hours.

By investing in a solar PV system, Southern Plumbing Plus wanted to reduce their electricity bills for their Fyshwick address, but having a positive impact on the environment was also an important factor in their decision. Thanks to solar, they are now achieving substantial savings while reducing their carbon footprint, and increasing their energy independence from the grid.


Technical Specifications

Technical Specifications


After conducting a comprehensive energy analysis, we assessed that a 99.9kW was the best system size to reach maximum profitability. We had just enough space to fit this amount of panels on the warehouse roof, while leaving enough room around for maintenance and repair, if ever needed.

Southern Plumbing Plus was after higher quality, long-lasting components, and therefore opted for SolarEdge inverters. This allows us and the client to monitor each solar panel individually and to intervene if some are underperforming throughout the lifespan of the system. There are also minor obstructions on the roof that shades a few panels in winter, and SolarEdge copes much better against this type of situation compared to basic string inverters.




The system being fully operational for more than three years now, we have sufficient data to properly assess the overall performance of the system and compare it to our initial savings and performance estimates.

We predicted that the average daily performance of the system would be 385kWh a day. In reality, the system is producing 383kWh a day. We expected a payback in 5 years, but because of steep electricity costs, it was achieved after just 3.1 years. This means that the system has already paid for itself, as of April 2021.

Over the full warranty period of 10 years, we assess a gain of $253,000 out of this investment. It is important to note that the total savings could be much higher if the system produces for more than 10 years, which is very likely.

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