Green co-leader Russel Norman's election campaign pledge would see loans of up to $15,000 offered to those who install the panels, to be repaid over 15 years through rates bills.
Making the repayments that way would mean the loan, like the solar panels, would remain with the house when the property changed hands.
Prime Minister John Key says the policy will only push up power prices and drive out competition.
Energy Minister Simon Bridges says the scheme is ''more magic money''.
Everyone wants something cheaper but someone has to pay, he argues.
Solar is about three times more expensive than grid-scale generation from wind, hydro or geothermal power stations, and if solar power is to be made more affordable other taxpayers and power users will have to pay for it, he says.
Putting aside, for a moment, the Government paying a $30 million subsidy to keep the Rio Tinto-owned Tiwai aluminium smelter operating and sweeten the partial float of Government-owned Meridian Energy (and the fact Rio Tinto last week reported a $4.45 billion annual profit): the Green proposal on solar energy deserves deeper scrutiny.
According to Dr Norman, the biggest obstacle stopping most families from going solar is the upfront cost.
This is where he sees leveraging the Government's lower cost of borrowing to allow tens of thousands of homes and businesses to install solar power, at virtually no cost to the taxpayer.
A typical system will produce $1000 of electricity a year at current prices, and cost $900 a year over 15 years to pay off, leaving the owner $100 better off each year, he says.
Over 25 years, the average family unit will produce $28,000 worth of power without a single government subsidy in sight - just a loan guarantee over a secure investment.
Dr Norman claims the Solar Homes policy will create up to 1000 new green jobs and boost economic development throughout the regions.
Dr Norman points to the Green's Heat Smart home insulation initiative as proof the Solar Homes policy could succeed.
About 230,000 homes have taken up the insulation scheme, a significant increase on initial estimates, making the houses much warmer and drier.
The Solar Homes policy envisages excess electricity generated by households being sold on to the national grid.
However, the Energy Efficiency and Conservation Authority has previously warned that in many cases, setting up and using a grid-connected system costs households more than using grid electricity over the lifespan of the system.
It is also worth knowing why most of the other benefits with grid-connected systems do not apply here in New Zealand.
Around 75% of existing generation is from renewable sources in New Zealand, and new generation is almost all from renewables, the authority says.
Since New Zealand's grid electricity uses very low carbon, switching to solar for some electricity use will not reduce carbon emissions from households.
A solar photovoltaic panels system means you need to be using energy in the house during the day when the sun is shining and the system is generating electricity.
The amount the electricity retailer agrees to pay for excess is another key figure in determining the economics of a grid-connected system.
Generally, excess electricity will be sold off significantly less than the retail price, meaning most grid-connected systems will never pay themselves off, let alone reduce energy bills or make money for the owner.
With some people still keen on renewable energy, and as long as wind turbines are not built on hills near where they live, solar energy may be the generation tool required as it captures the high amount of sun New Zealand receives in a normal year.
There may be other ways to increase energy efficiency and lower costs, but that does not mean serious consideration should not be given to the proposal from the Greens.
New Zealanders are increasingly concerned about the price of electricity and any debate on how this can be addressed should be welcomed, not dismissed without proper thought and research.
