If you’re considering switching your home to solar, you will be wanting to find out how many solar panels you will need to meet the energy requirements of your household. It comes down to the capacity of the system you choose to install, and the quality of the panels, but the average New Zealand household will need 15-20 solar panels to power their home.
Calculating the capacity of the solar energy system you need
When we talk about solar system capacity, we talk about the kW rating, which is the maximum amount of energy the system can generate at its peak output. For households this would commonly be a system with a maximum output of 5kW, with commercial operations generally requiring systems 6kW and over.
Check out this guide put together by Unison NZ to calculate the size of the solar panel system your home will need. You also need to consider your budget, the amount of optimal roof space you have, and whether you are wanting to use solar power to just supplement your energy use or completely take your household off the grid. To learn more about which size could be right for you, you can read our comparison between 3kW and 5kW systems.
A larger solar energy system uses more solar panels
A 2kW solar panel system is typically made up of between 6-8 solar panels (depending on the quality of the panels), using an area of around 10-15m2. A 3kW system is typically made up of between 8-12 solar panels, using an area of around 15-20m2. A 5kW system is usually comprised of 15-20 panels, so the total rooftop area needed for a 5kW system is around 25-35m2. A 10kW system generally needs 30-40 solar panels, so around 55-70m2 of space. Modern, high quality panels are more efficient, so you will need less of them to run a house.
You don’t need ‘extra’ solar panels beyond your home’s energy requirements
To get the optimum value from your system, its capacity should closely match your electricity usage. Buy-back rates from exporting your excess energy to the electricity grid are not high enough in New Zealand to totally offset the cost of investing in a much larger system than you need.
How many solar panels are needed to power appliances, electric vehicles or spa pools?
When you’re installing a solar power system, you may want to think about your future energy needs. If you’re planning on adding an extra fridge or buying an electric car in the near future, you may want to add capacity to your system accordingly. Here are some common products and the amount of solar energy they generally require per year.
| Product | Average annual kW required | Estimate number of solar panels needed |
| Refrigerator | 600 | 2 |
| Air conditioning unit | 215 | <1 |
| Central heating | 1,000 | 3 |
| Electric car | 3,000 | 10 |
| Heated swimming pool | 2,500 | 8 |
| Spa pool | 3,300 | 11 |
To make sure you get the best value out of your system, our solar energy professionals can assess your needs through a free at-home consultation. We take into account our current and future energy consumption and the times of day you consume it, your roof size and budget to determine how many solar panels are right for your household. Get in touch to get started on your solar energy journey today!
