How To Calculate Your Solar Energy Potential
Sunshine hours can be a difficult thing to measure if you don’t have your own Campbell-Stokes recorder - but never fear! Whether you are building a new house or looking at adding solar to your existing property, we’re here to guide you through the process of figuring out how much solar energy potential your property may be able to generate through the average year.
The amount of solar energy your home can create will depend on a range of factors, including:
- the sunshine hours in your region
- the size of your roof
- the angle of the panels on your roof
- the number of solar panels you decide to install
How much solar energy does the sun produce?
It is estimated that the Sun produces 384.6 yotta watts of energy* in the form of light and other forms of radiation at any given point of time. If you are not familiar with that unit of measurement it is 3,846 with 21 zeros after it. That is one huge number!
While most of that energy is lost to the depths of space, a small portion of it makes it all the way to Earth, through our atmosphere and to the surface.
Our solar energy systems start at a 6 panel 1.74kW System, with our Supreme System going up to 4.6kW, 16 Solar Panels, and a 4kW Inverter. If you require even larger, we’ve got you covered.
How much power your solar energy system produces will depend on a range of factors. Read on to find out how the size of your property and roof set up will affect your solar energy potential.
*At sea level on a clear day with a surface directly facing the sun's rays.
How many sunshine hours do you typically receive in your area?
Calculating solar energy, or solar energy potential, in New Zealand, is something usually done by first understanding the size and landscape of your property, alongside the median sunshine hours for your region, city, or suburb. NIWA is a Crown Institute charged with monitoring New Zealand’s climate, weather, environment, and water. They have over 100 climate monitoring stations around New Zealand that monitor sunshine hours and other climate indicators, and produce quarterly and annual reports on the local weather patterns. You can view their mean monthly sunshine hour reports here, or annual climate reports here.
If you live in Auckland and are interested in knowing more about the sunshine hours and how they’re calculated for your region, check out our blog on Auckland sunshine and solar energy here.
If you’re a little further South in the Waikato, you can also read our Hamilton sunshine and solar blog here.
How big is your property?
The size and dimensions of your property will have an impact on how many solar panels you can place on your roof, at what angles they should be installed, and how much solar energy you could potentially generate.
How is your roof set up?
The slope and azimuth will impact system losses and your house’s potential. Similar to a compass, azimuth measures a bearing from true North. For example, an object due north has an azimuth of 0°, one due east 90°, and so on. An average system size of 3kW would require about 24m² of roof space.
The ideal roof for maximising solar energy production in New Zealand has a 30-degree slope and faces true North. But the reality of housing in New Zealand is that many properties are not designed at this optimal orientation, particularly when we have so many hills to navigate. If your roof isn’t facing North, never fear - our team of expert installers will be able to make the most of your home’s positioning on the property using a variety of techniques, to ensure your solar panels are positioned in the most productive way possible.
Note that in some circumstances, a split array of east and west is a better solar solution. This is due to utilisation of energy being higher in the morning and afternoon, when east/west arrays generate the majority of their electricity.
Interested in calculating the solar potential of your roof? Use our online tool to get a quick estimate. Then, book in a Free In Home Assessment with one of our trained technicians, who will come up with a solar solution that works for you.
How do I manage my energy usage?
It’s a good idea to track your electricity usage data, to better understand how much electricity your household uses. Many retailers offer running cost calculators. These can estimate how much energy your home appliances require on a monthly basis.
Alternatively, for a general overview you can compare your monthly usage by looking through your old power bills or you could install smart plugs to get an accurate reading of any appliances you feel might be particularly power hungry. HRV has a smart meter that can measure the total and individual consumption of each circuit in a house. There’s also an app for it so you can check your electricity usage at any time. Give us a call for more information.
We’re here to help you use solar power in the most efficient way possible. Check out our handy tips on maximising the benefits of solar power for your home.
Once you have visibility of your energy usage, there are a number of ways to level up your home’s energy potential.
Are you considering getting a battery?
Buying a solar battery means you may be able to store energy for use during non-sunshine hours, whether that’s at night time or just in the middle of a particularly gloomy, cloudy winter’s day. You’ll have more energy potential, especially if you’re not home during the day.
When choosing one of our solar energy solutions, you can also choose to include a battery. Our go to battery is the Tesla Powerwall 2, which is compact, stackable and comes with a built-in inverter - the ultimate trifecta! The Powerwall has a usable capacity of 13.5kWh, which according to Vector is the equivalent of powering an average two-bedroom home for a full day.
Interested in how the Tesla stacks up to other options currently on the market? Why not compare the performance of the Tesla Powerwall to some of the other popular battery storage models.
Have a read of our Tesla Powerwall 2 Review to learn more!
Can I sell solar power back to the grid?
If you generate your own power, by using solar panels for example, there may be the opportunity to sell any surplus power back to the grid. Each power company sets its own ‘buy-back’ prices so it pays to check directly with your provider.
If you plan to re-sell excess electricity, HRV sets up an agreement with the retailer for our customers. Households will need to install a two-way meter following solar installation to accurately measure electricity imported from the solar panels.
Considering solar energy or solar panels?
Whether you’re building a new home and want an alternative energy source, fitting out a rental property, or improving the family home, solar energy in New Zealand can be a nice option for your in-home energy and power. If you’re considering solar energy you can first try our solar calculator to see our estimate of the solar energy potential of your home based on some key information provided by you.