Nowadays solar power and solar technology are concepts that sit at the forefront of our minds; as we all grow more conscious of ideas around sustainability and environmentally friendly choices. Most of our clients who come to us to design a new home, or extensive renovation, request that solar power be considered within the design.

Harnessing power from the sun, going “off the grid”, and utilising future proof technologies seems like a no brainer and appeals to those looking to save on seemingly ever increasing power bills. However it’s important to have the current know-how on where solar technology is at. Knowing what it is and isn’t capable of while being mindful that a worthwhile solar power system is a significant up-front investment is a great starting point.

‘Solar power’ refers to an array of photovoltaic panels, which are usually fixed to a north facing roof. The panels contain photovoltaic cells made of silicon, which convert sunlight into direct current (DC) electricity. This is sent to an inverter which converts DC to alternating current (AC), which in turn is either sent directly to your electrical fixtures and fittings, or to your battery storage.

Below is our quick-fire guide of how to determine if solar is right for you.

Defining your individual solar requirements accurately, requires an analysis into your whole lifestyle:

  • How many people are in your family?
  • How often are people home? Are there usually people home during the day?
  • How big is your home? How is it orientated to North?

Supplement power bill or self-sufficient?

Do you want to save a few $ on your power bill, or ensure you’ll still have power in a natural disaster? Most people want to still have access to the grid, just in case. Therefore family homes within most urban to semi-rural settings are usually best suited to a ‘supplementary’ system. In contrast, a small bach on a remote beach which is only used in summer will be better suited to a self-sufficient array. You need to consider and define what you want to achieve.

How much power do I need | What size array?

A typical array for a small family home is around 3.5 kilowatts (kW). A large array for a residence is considered to be 5kW or over. A good rule of thumb to stick to is a kW per person. Each panel is typically around 1.7m long and just over 1.0m wide with a 250-320 wattage. The panel module allows you to add to your array, as your lifestyle needs change. For example; a couple may start with a 2.5kW array, but add more panels up to 4kW after the arrival of their second child.

What roof will I need?

The ideal solar array orientation is north facing, but anything from north-east to north-west is suitable. Flat roofs will not be as exposed to the sun as pitched ones, and are therefore less effective – the ideal pitch being anywhere from 15° – 45°. If your design preference is for super sleek 3° roofs you may want to consider a free-standing array elsewhere on your section, rather than a roof mounted one.

Do I need batteries?

Without batteries, you have no capacity to store the power your solar array generates – so you (or your appliances) need to be able to utilise the power as it is generated (which is during the day). For most people, battery storage makes sense when going to the expense of installing an array. Batteries are available in a variety of stroage capacities and with them you can store excess power. You can then draw this stored power anytime, and in some cases you can ‘feed’ excess power back into the grid.

The downside is that batteries are generally the most expensive component of the whole system. You can have an array without them, but would still need to be tied to the grid to ensure a consistent power supply. Batteries are slim and can be wall or floor mounted, usually in a garage, so have a think about your wall or cupboard space. A few recently designed batteries can also be externally stored. Again, these can be added to or exchanged as the technology improves and becomes more affordable.

How much does it cost?

Based on information taken from a consumer article last year, the average cost of a 3kW array (with no battery storage) is around $10k including GST. This price can increase two or threefold when batteries are included in the system. However this can be made a little more palatable with certain banks offering a subsidy for solar power as part of a home loan. There is an industry expectation that battery prices will become more affordable in the coming years. For this reason, we often specify “array only” systems, but make provision for future battery storage.

Want more info? Here are some excellent resources;

As an accredited Homestar practitioner and assessor, we have the experience and expertise to incorporate thoughtful and high performance solar technologies into your home.

Questions? We’d love to hear from you. At Mackit Architecture we design bespoke residential architecture for discerning clients. Based in Greytown in the Wairarapa, our team design beautiful, practical and enduring new homes or renovations both locally and New Zealand wide.