Plan your solar system

For a small system, you need space on your roof for at least 8–12 panels and they’re usually around 1.6 to 2 square metres each. If you have enough outdoor space, you can consider mounting panels on the ground instead.   

High-end, efficient panels can be used to generate more power per square metre if space is limited, but they can cost more. 

• Ideal — 70 square metres allows up to a 10 kW system.
• Good — 35 square metres allows up to a 5 kW system.
• Poor — Less than 20 square metres is too small for a 3 kW system.

• Ideal — North, northeast or northwest facing.
• Good — West or east facing.
• Poor — South facing.

• Ideal — A steep roof tilt of 30° to 45° generates maximum electricity.
• Good — A medium roof tilt of 15° to 30° generates enough electricity.
• Poor — A flat (less than 15°) or very steep roof tile (more than 45 °) won’t generate as much. Racks can be used to get a better angle with flat roofs but will add to the cost.

• Ideal — New or recently rejuvenated roof.
• Good — Doesn’t need replacement or major maintenance within 10 years.
• Poor — Needs replacement or major maintenance within 10 years.

• Ideal — No shade on the roof.
• Good — A bit of shade on the roof early or late in the day.
• Poor — Lots of shade on the roof during the day.

If your roof is unsuitable or you don’t want to put panels on it, a ground-mounted solar system may be an option.

• Space required: The panels are installed in groups called ‘solar arrays’. The amount of outdoor space you’d need depends on how much capacity for solar power you want (more capacity means more solar arrays).
• Benefits: A ground-mounted system gives more control over the orientation and tilt of solar panels, which can help to maximise solar power generation. Being on the ground also means the system is easy to access for checking and cleaning.

While you don’t need building consent, there are still rules that a ground-mounted system must comply with. They differ depending on whether you live in an urban or rural area.

Rules in urban areas

A ground-mounted solar installation in an urban area must comply with the Building Code, your council's district plan rules, and any other relevant legislation.

For example, there are restrictions on the size of the solar arrays, and their distance from neighbours, roads, railway lines and legal boundaries.

It's worth getting professional advice before deciding to go ahead with ground-mounted solar.

View rules for ground-mounted solar in urban areas(external link)

Rules in rural areas

There are no size restrictions for ground-mounted solar arrays in rural areas, but you still need to comply with installation rules, and all other relevant legislation.

For example, resource consent may sometimes be required, and solar arrays must be at least 5 metres from any residential building, public road, railway or legal boundary.

Get some professional advice or talk to your council to ensure any plans will be compliant.

View rules for ground-mounted solar in rural areas(external link)

When you maintain a grid connection, you pay for electricity when your solar system doesn’t generate enough power. You can also sell any solar electricity that you don’t use back to your power company (or store it in a battery).

To be independent of the electricity grid, you need a very large solar system with batteries (or a fossil fuelled back-up) to power your home outside of daylight hours, or when there is an outage.