Solar energy

When it comes to solar energy, there’s plenty to go around. With more Kiwis plugging into solar as a renewable resource to power their homes, does it make sense for you? 

How it works 

Solar electricity systems (also known as photovoltaics, PV systems, or solar panels) convert sunlight into electricity through solar panels on your roof. When sunlight reaches them, semiconductors in the panels create an electrical current, which is then converted into a form your household appliances can use – anything from toasters to spa pools. 

Most homes with solar power are also still connected to the electricity grid (‘grid-tied’). That means you can still use power from the grid as a backup when your solar energy system isn’t generating enough for your needs, or at night. 

If you’re grid-tied, any excess power you generate gets sold back to the electricity grid – although ‘buy-back’ rates are typically a lot lower than what you pay for electricity. It’s generally better if you can use all or most of the power you generate.

Solar panels can still generate electricity when it’s cloudy or raining, but it’s much less efficient than when the sun is shining. You can also store excess solar energy for use when the sun isn't shining by adding batteries to your solar power system – more on that below. 

Learn more about solar energy

How much it costs

It depends on the type and size of system, but according to EECA’s Gen Less Solar Tool the average system size is 3kW and likely to cost around $2,000 per kW installed – although costs are coming down as solar becomes more popular. 

Storing solar power in batteries

Excess power can be used to charge batteries, which you can draw on when there’s insufficient or no solar power being generated (such as at night). Batteries even make it possible to go completely off-grid, although most New Zealand homes with solar energy systems are still connected to the electricity grid.

The downside is that batteries are expensive – anywhere from around $6,000 - $20,000 depending on the type and capacity – which can have a big impact on the cost-effectiveness of a solar energy system. Source: My Solar Quotes

Keep in mind too that you’ll probably have to replace the battery over the life of your system. The good news is that like solar panels, the price is coming down as they become more popular – but do your sums to figure out whether the extra cost makes sense for your home.

Good Energy Upgrades are just one step away


Solar panels have a life span of around 25 years and are pretty low-maintenance. Mainly it’s a matter of keeping the solar panels clean, which you can do yourself, to ensure there’s nothing stopping sunlight reaching them.

You may also need to replace the inverter during the life of the system.

Benefits — for you and the planet

Reduce burning fossil fuels

While most of New Zealand’s electricity comes from clean, renewable sources like hydro, a portion is still generated by burning coal and gas. By using solar energy in your home you’re reducing the need to burn fossil fuels for electricity – and reducing the greenhouse gases they emit.

Less impact on the environment

Solar energy has less impact on the environment than other renewable energy sources – e.g. the effects of hydro dams on surrounding ecosystems and habitats. Solar energy requires no water or additional land – just a sunny roof.

Is solar power right for you

It depends on a range of things, including your home, how much power you use, and how and when you use it. And while solar is suitable in most parts of New Zealand, it’s a particularly good option in sunnier regions like Northland, Auckland, Nelson, Bay of Plenty and Marlborough. 

You get the best return on your investment in solar power if you can use as much as possible of the power you generate. That’s because the price you receive for selling electricity back to the grid is generally lower than the price you pay to buy electricity.

Most solar power is generated during daylight hours, so solar is usually cost-effective if you use a lot of electricity during the day or can store the energy overnight, for example in an electric hot water cylinder. If you’re working from home, you’re charging an electric vehicle, heating a spa pool or similar, solar can be a great option. Shifting your ‘normal’ power consumption e.g. by using timers or setting things like dishwashers or washing machines to run during the day can also increase cost-effectiveness. 

Other things to think about

Solar panels obviously work best when they get as much sun as possible. So consider whether your roof is in shade from trees, other buildings or might be in the future. 

You should also consider the condition of your roof – once solar panels are installed it’s difficult to do roof maintenance or repairs so consider whether your roof will last as long as the solar energy system. 

It’s also important to remember that before you consider installing a solar energy system, that you’ve invested in adequate insulation, efficient heating, coverings or double glazing and that you have sealed any draughts and filled any gaps in doors and windows.

Check the return on investment for your home

The Gen Less solar tool could help you assess the estimated financial return of solar electricity for your home. 

How to get a solar power system for your home


HomeFit self-assessment is a straightforward way to check if a home is warm, dry, efficient and safe. You can use it to check a home you’re looking to buy or rent, or if you want to know how you can improve your current home. It starts with a simple online check.

If you would prefer to speak to someone you can contact an independent HomeFit assessor who can visit your home to provide a detailed assessment and list of priorities. 

HomeFit was developed by the New Zealand Green Building Council and is proudly supported by ANZ.

Important information

The material is information only and you should seek professional advice about your circumstances. While we’ve taken care to ensure the information is reliable, we don’t warrant its accuracy, completeness, or suitability for your intended use. To the extent the law allows, we don’t accept any responsibility or liability arising from your use or reliance on this information.