One in five rooftop solar systems are deficient and thousands of Australians are being denied lower power bills because their household solar delivers less electricity than promised, new data shows.

As the number of rooftop solar systems on Australian homes and businesses tops 1.8 million, there are calls for stronger safeguards to weed out dodgy operators and ensure the technology’s benefits are fully realised.

The Clean Energy Regulator found one in five rooftop solar systems were substandard. Credit:Jason South

The Clean Energy Council, which accredits 5000 solar installers in Australia, cancelled 13 accreditations this financial year and temporarily suspended 153 installers.

NSW Fair Trading has received 3327 complaints about the photovoltaic industry over the past five years, while Consumer Affairs Victoria received 6436 in the four years to June last year.