Solar power turns heads in the home buying market. Potential buyers are invariably impressed, say agents.

The panels that are increasingly dotting roofs across the country save homeowners money on electricity. They also add to the green credentials of some.

The growing proliferation of panels is driven in part because of the falling cost of installing systems and improvements in technology, which make the hardware more efficient.

Mike Pero Real Estate agent Terri Newman-Hodge is selling two properties with solar power. The one that really impresses buyers is in New Lynn. The property's octogenarian owners installed a $30,000 system three years ago and their electricity bills are only a few dollars a month, Newman-Hodge says.


The system provides power and hot water heating and has a diverter, which means power production is fed back into the grid when not needed.

Barfoot & Thompson agent Jannette Wouters is currently selling a four-bedroom property at Strathnaver Crescent Lynfield, which comes with solar water heating installed.

"When I mention this (to potential buyers), they say: 'Great'," says Wouters. "Hot water is about one third of your power use. The owners tell me it saves heaps of electricity."

Solar King's general manager Roy Maddox says more buyers are becoming aware of the running costs of houses and are looking for energy efficient properties.

Solar power combined with good insulation and efficient heat pumps make homes increasingly desirable to buyers he says.

There are many choices when installing a system. At the most basic level is solar water heating, which only heats the water in the house. A hot water system for the house costs around $8000, says Roy Netzler, managing director of Solar Group. These systems suit households where the occupants are out during the day and can't as a result take advantage of daytime solar power. A hot water system heats up the water and stores it for the evening.

Maddox says a modern solar power system costs from $4995 fully installed, but most people spend around $8000 to $10,000 on a 3kWh system suitable for a medium-sized home.

It is becoming increasingly common for Kiwis to heat their pools. Pool solar heating systems have 10-year warranties, he says, and should last around 20 years with totally free pool heating for that time.

One downside is that solar systems don't last forever and people who buy a home with an older system might be wary of maintenance costs.

Solar panels should last 25 years, says Maddox, and the inverters and controllers, will last around 15 years. They can be replaced without replacing the panels.

Buyers need to beware that there is a movement by lines companies to charge solar panel users extra to be connected to the grid.

Hawkes Bay's Unison Networks says solar power users still need to fall back on the grid on cloudy days and they need to pay their fair share of maintaining the network.

Other power companies have reduced the amount they pay for surplus electricity generation from private solar power systems that is fed back into the grid.

In the past many of the companies paid homeowners between 25c and 30c per kWh fed back into the grid. That has dropped to as little as 6c. This means it takes many more years to get pay back on your initial outlay.

Inevitably new models of charging will evolve. In March, P2 Power, which bills itself as New Zealand's first peer-to-peer solar electricity provider, came to market.

The SolarShare offering from P2 works by sharing solar power between households and businesses, on Vector's network.

When there's not enough local power to meet the customer's needs, the rest is supplied via the traditional grid.

P2 launched on Waiheke Island because of the island's eco-conscious reputation as a community, but plans to start competition in other parts of New Zealand. The company pays 16c per kWh for the first 50kWh exported each fortnight, and 8c thereafter.

It is possible to go totally off the grid by storing excess daytime power production in a battery bank, which can be expected to last around 15 years. Currently, however, it's not really cost efficient, says Maddox.

"Batteries are available. But they are not financially viable yet," says Maddox.

"You are looking at a $10,000 cost to add any meaningful battery storage."

Though solar power might not be worth the outlay for some people if they judge the return solely in terms of power savings, it can make a property more desirable to buyers.