Calculating whether solar panels will save homeowners money in the long run has become near-impossible after a spat between a government agency helping Kiwis future-proof their homes, and the solar power industry.
The dispute centres around an independent, peer-reviewed online calculator, which for two years was available free on the Government's Energy Efficiency and Conservation Authority (EECA) website.
Electrician Leo Fouhy says the calculator was great, "because it gave you a pretty good idea on what your return on investment is".
The calculator is no longer there after some intense lobbying from the solar industry, aimed directly at EECA.
"There were some complex issues that need to be worked through obviously to make it accurate," said Jenny Lackey of EECA.
The calculator was funded from a $6 million pot of taxpayer money allocated to research on renewable energy.
Canterbury University, which built the calculator, told 1 NEWS it's not possible to say how much of that $6 million was spent on building the tool. But the university says the tool is reliable, accurate and peer-reviewed.
In October last year, the Sustainable Energy Association made its feelings clear - it wanted the website taken down.
"If it was right, it would still be running," said Brendan Winitana of the Sustainable Energy Association.
The Energy Minister wouldn't comment to 1 NEWS, citing it as an operational matter.
EECA did agree to take the calculator down.
"The amount of energy you use yourself is so crucial to the sums, we have to make a kind of technical adjustment," Ms Lackey said.
But the lobby group, the Sustainable Energy Association, has its own solar tool online, although they won't call it a calculator.
"It's called an optimiser," Mr Winitana said.
That 'optimiser' tells you solar will save you money every time.
Whether that's really accurate could be made clear once the university's calculator is back online - expected to be in the next few months.