Low cost energy

Over the lifetime of a rooftop solar system, the electricity generated costs far less per kWh than electricity from the grid.  

Another way of looking at it, is that once the system has paid itself off, you’ve effectively got free electricity from the solar. 

If you’re looking to install a rooftop solar system, there are options to buy the panels outright, or finance your purchase over a number of years, with many lenders offering low-interest ‘green’ loans. 

What you need to know

  • Upfront costs

    Around $10,000 for a medium-sized installation which provides approximately half of the energy needs for an average household (without EVs).

    For households with EVs, larger installations could be worthwhile. 

  • Savings*

    If you include the upfront costs, divided over the 30-year lifetime of your solar panels, electricity from rooftop solar works out about 75% cheaper than electricity purchased from the grid (6c/kWh compared to 24c/kWh) when finance costs are excluded. 

  • Finance options

    There are finance options available that can offer zero upfront costsmaking solar more accessible to more homes.  

  • Features

    • Zero operational emissions
    • Increased resilience when coupled with home batteries
  • Lifespan of tech

    25-30 years. During this time there will be a small decrease in output from the panels (approximately 0.5% per year) and it’s likely that you’ll have to replace the inverter.

  • Install

    You’ll need to have your rooftop solar system installed by an expert (this must meet current standards).  

For an average 3-person household that has all electric appliances, and where people are home during the day, the costs saved on electricity will pay off the upfront costs of rooftop solar after around 8 years.

EECA analysis using the Gen Less Solar Power Calculator**

Why install rooftop solar 

  • Increasing affordabilityThe upfront cost of installing rooftop solar has been consistently decreasing over the years as systems are more widely adopted. If it hasn’t stacked up for you previously, it may make more financial sense now. 
  • Power your big energy-users Hot water, electric vehicles, swimming pools, spas and hot tubs can all be powered using energy generated from your solar PV system. 
  • Better value during the day – If you’re at home during the day, or can utilise smart tech like a home energy management system to optimise charging, wash loads, or water heating for this time, you’ll utilise more of the energy that you generate.  
  • Sell the excess You can sell the electricity you don’t use to your retailer (although, this is typically for less than you’d pay to buy it from them). 
  • Zero emissions – Installing solar will reduce your home’s emissions by utilising your home-generated renewable energy, rather than grid electricity (which is around 80-85% renewable).
  • Never mind the clouds While solar panels will produce the highest output in the sunniest regions, they perform well all across the country.
  • Minimal maintenance The life expectancy of a solar panel is 25-30 years, with only minor decrease in output during this time – approximately 0.5% per year.

How rooftop solar works

Rooftop solar converts sunlight into electricity, using solar photovoltaic (PV) panels that are positioned toward the sun. They work by harnessing light energy (photons) to produce an electric current.

Solar PV panels can be installed on the roof of your home, garage, or even in your yard – wherever they will capture the most sunlight.

Solar systems can either be connected to or independent of the New Zealand grid. Generally, maintaining a grid connection will cost less than enabling your system to provide you with constant power – unless you live somewhere without existing lines.

Grid-tied solar – Most homes with solar panels stay connected to the electricity grid. They pay for electricity when the solar system doesn’t generate enough electricity – and can sell excess electricity that isn’t used back to retailers (or store it in a home battery).  

Off-grid solar – Some houses in New Zealand are completely independent of the electricity grid and rely on very large systems, batteries, or fossil fuelled back-ups to store and power their homes outside of daylight hours.  

Better with batteries?

Like solar panels, home batteries are becoming more affordable and accessible for New Zealand homes. As these prices drop, New Zealand homes and communities can benefit from the cost savings and resilience they offer.  

  • A home battery can store solar generated electricity to be used within the home when it’s dark outside – meaning less ‘additional’ electricity needs to be purchased from the grid outside of daylight hours.
  • Batteries can provide backup power in an emergency, which can be particularly beneficial in rural areas.   
  • Batteries are being installed in NZ homes for around $7,000 to $14,000 – and may be financed at a low interest rate using a green home loan.  

Assess the value of solar for you 

Answer a few questions about your house location and power use, and you’ll get a detailed report estimating how much value you could get from solar. 

Common questions

It pays to go electric

Powering your home with efficient, electric appliances can save you in energy costs and slash your carbon footprint.  

We’ve done the math on key household energy uses such as heating, water heating, cooking and driving. The numbers show that the most efficient electric options make sense financially – both in terms of monthly running costs and overall lifetime costs. 

Discover how your household might stand to benefit from going electric. 

Read next