Choosing a solar installer and supplier is an important task. You want to make sure that you will be getting a quality system and that you can trust the installer to do the best job for you.

Frequently Asked Questions

There’s a lot to consider when purchasing a solar power system.  Please have a read of the questions we’ve been frequently asked below. You can also  download our Solar Guide to learn more about the various options and they key questions you need to be asking. And if there’s something we haven’t covered please don’t hesitate to contact us in person. Our solar engineers are very good at explaining things clearly.

Is there enough sunlight for solar in the lower North Island?

Our area has plenty of sunlight hours to make solar power a worthwhile option. Germany is an example of a country with lower sunlight hours that has a large amount of solar installed and is now reaping the benefits. Nelson and Blenheim may get 30% more sunshine hours than Palmerston North, however modelling across the course of a year shows that the generation from solar panels in Palmerston North is only 9% less than Blenheim or Nelson. This is becuase bright sunshine is not a requirement for consistent solar generation. Modern solar panels are 50-80% productive even under clouds and rain, and are definitely worth the investment in places with less sunshine or even where snow is prevalent.

Should I wait for the technology to improve?

Every few months we see a TV or newspaper report about an exciting new solar technology that is going to change the world of solar, promising lower costs, better efficiencies and higher outputs. There is some fantastic work being done in the field of solar research, but existing solar technology has been around for 30-50 years and is mature and stable.

We expect that there won’t be any new “silver bullet” solutions  in the solar world, but instead we will see small improvements in panel efficiency, battery reliability and capacity improvements, and panel level optimisation technologies like microinverters. If you hang around waiting too long for a new technology to come along, you might just miss out on the benefits solar could be giving you in the meantime.

Our experience shows that prices are generally staying the same from year to year, however solar panels are improving in efficiency by about 5% annually. That’s great, but the 5% improvement is much less than the typical 8-12% return on investment that installing solar will give. What this means is that any reduction in cost due to waiting is going to be less than the savings you will make from investing in solar right now.

What if my roof doesn’t face North?

Solar power systems generate most if installed on roofs facing anywhere from due east to due west. North is best for absolute production, however a west facing roof will generate more power in the afternoon which can suit the times that power is used after people arrive home from work. Conversely an easterly facing array will generate more power in the morning. However all things being equal, the more north facing the roof is the better. East-West layouts generate about 15% less power than a 100% north facing array. This can be compensated by adding an extra panel or two to increase generation.

What if I have a flat or low pitched roof?

We recommend a minimum installation tilt angle of 10 degrees. This will allow for rain to self-clean the panels. Solar panels can be installed on tilt frames for roofs with a lower pitch than this or for roofs with a negative pitch (i.e. roofs that face south).

What size system will I need?

The size of system you should install will depend on several factors. These include:

  • Your electricity consumption. Larger users will need more solar panels to get the equivalent bill reduction than smaller users.
  • How many panels will fit on your roof.
  • Your budget.
  • How much electricity you use during the day time. If someone is home during the sunny hours of the day you will be able to consume more of your self-generated power and therefore will get more benefit from a larger system.
  • Your future plans for expansion. Micro inverter systems are easy to expand. This means you can choose a smaller system initially and expand it later.
Can I zero my electricity bill?

It is possible to reduce your bill to $0. However, in New Zealand the price paid for exported power is much less than what you pay for imported electricity. To achieve a net zero bill requires a very large system with batteries that is expensive to install. A large system can like this can reduce your average annual costs to nil, but you will end up exporting a huge amount of power in the summer and the low price for exported power means that it will take a longer time to recoup your money. Normally, we recommend sizing your system to reduce your electricity costs by 40 – 60% as this is the sweet spot that balances initial cost with investment returns.

Is there any government rebate?

No. New Zealand has an electricity generation system with about 85% coming from renewable sources (hydro, wind, geothermal, solar). This means that the government has little incentive (unlike e.g., Australia) to provide subsidies for solar generation in order to meet its climate change objectives.

At the time of writing, the only ‘subsidy’ available is from Kiwibank. They offer a $2,000 grant towards the purchase of a solar electric system; however, you must have a mortgage with them.

If your mortgage is with Westpac, they will top-up your mortgage for solar solar panels with up to $10,000 interest free for five years.

How long will it take for the system to pay for itself?

Most of the solar systems that we install have payback periods ranging from 6-11 years. Note that this doesn’t include any potential value added to your property.

Does a solar system increase the value of my property?

Most probably the answer is yes. Please see the discussion on our Blog. The great thing is the more people start to understand solar the more they want it and the more value is placed on homes with solar.

A recent 2019 study from the US revealed that solar homes sell for an average of 4.1% more than their non-solar counterparts.

Are there finance options available?

If you are wanting to finance your solar system, there are several different options. We explain the options on our Finance page.

Once I have signed up, what’s the process?
  1. A 10% deposit is paid
  2. We prepare all the paperwork, obtain Network company approval and order a meter change from your electricity retailer
  3. We install and commission your system
  4. The system is tested by an independent electrical inspector
  5. We provide full documentation, explain how it all works and settle the final invoice

It generally takes three to six weeks to get your meter changed. Installation is arranged to take place after the import-export meter is installed. Depending on our workload, this usually occurs two to three months after your 10% deposit is paid The only thing you will need to do is change electricity retailers if you are not currently supplied with electricity from a retailer that takes solar customers.

How do I sell excess power and is it paid by the electricity retailer?

Your electricity retailer will take back whatever generated energy you don’t use, however not all electricity retailers will pay you for this exported power. Here are the retailers that do and what they pay to residential customers:


Rate per kWh of export

Contact Energy



Depends on where you live – approx. 9c


Depends on the spot price of electricity – approx. 7c














7c (or you can sell to any other Trustpower customer at a price you choose)

Note: The above details were correct at June 2021. Please check directly with your retailer for current prices.

How much does it cost to have an import export meter installed?

This depends on which electricity retailer you choose.


Cost to install

Contact Energy















$155 urban
$198 rural
$305 remote

Nova $180

Note: the above details were correct at June 2021. Please check directly with your retailer for current prices.

Do I need a building consent?

Generally, you won’t need to apply for a building consent unless your are installing the panels on a ground mounted frame. Solar Hot water installations do require building consent, but solar photovoltaic installations are classed as energy work and as such are exempt from the Building Act regulations. Photovoltaic installations must be installed by a registered Electrician and inspected by a registered Electrical Inspector. Electricians are regulated under the Electricity Act and must install solar electric systems in accordance with all applicable standards and regulations.

How long does installation take?

Most standard grid connected residential installations within 50km of Palmerston North are installed in a single day. Larger systems or those further away may take 2-3 days. Please be aware that weather can delay or extend installation time—particularly in winter.

Should I replace my roof material before I install solar?

If your roof is old and you are looking at painting, renovating or replacing it, then we recommend that the work be done before you install solar panels. We can uninstall, then reinstall, but this will end up being more costly if it has to be done after the panels are installed.

We will examine the condition of your roof during a site visit. If your roof is in poor condition we may not be able to install solar panels.

Will solar panels damage my roof structure?

Your roof has been designed to carry a lot of weight and will hold panels without the need for reinforcement. Solar panel framing is attached to the rafters, purlins or roof battens with screw fixings that are engineered to the highest winds that are expected for your location in accordance with New Zealand Standard AS1170.2. The load is ultimately borne by the roof structure not by the roof material. We can attach solar panels to any type of roofing and the number of fixings used is different depending on the wind zone, roof type, roof height, topography, roof angle, distance from the ocean, etc. The solar panels are clamped to the racking system and all screw penetrations are waterproofed, so the roof won’t leak. Our 10-year workmanship warranty fully guarantees against any roof problems, so you can rest assured that the solar panels will be attached in a compliant manner and will not cause any problems.

Will I need to upgrade my switchboard?

Most switchboards do not need upgrading. During our initial consultation or site visit we will advise you whether any additional work is needed. Sometimes we find a very old main switch or a switchboard that is too full to add the circuit breakers that solar will require. In these cases, we will do the upgrade work at the same time as the solar installation.

Can I monitor my system online?

All our systems come with free online monitoring. The Enphase micro inverter system is particularly sophisticated. You can see exactly how much power you have generated, consumed, imported, and exported. You can view it on your computer, smartphone or tablet. You can view historical information and even see what the weather was like on any day in the past.

As the system owner with a micro inverter system, you will be alerted if any part of your system has a fault—right down to the individual panel level. This level of monitoring is a powerful feature of the Enphase micro inverter system.

If my energy requirements increase, can I upgrade the system?

Yes. We use micro inverters in most of our systems. This means that extending your system may be as simple as adding more panels and micro inverters on your roof. Sometimes a new circuit may need to be run up to the roof if you are adding a lot more solar panels.

We also upgrade string inverter systems. Sometimes we can can source matching solar panels and can extend an existing string. In other cases we will add a new string inverter or micro inverters in parallel with your existing system.

Can you retro-fit battery backup into a grid connected system?

Yes. All our systems are compatible with batteries for self-consumption and backup. Adding a battery can be costly, although prices are slowly dropping.

If you eventually want to be off grid, it is best to make that decision at the outset. Off grid systems use different types of inverters that are designed to provide high surge currents to support loads when the grid is absent. While we can turn a grid connected system into an off grid system it is more cost effective to provide for that from the beginning.

What happens on cloudy days?

Your system will still produce electricity during cloudy days however production will be less than on sunny days. This also means that generation is less in winter because there are more cloudy days in winter and the days are shorter. A typical annual generation curve looks like this:

cloudy days

With a grid connected solar system, on cloudy days when generation is less, your propoerty will automatically draw power from the grid if there is not enough solar generation to supply the load. Your solar generation is used first, and after that any further power is supplied from the grid so your appliances will still run as normal.

If your system has batteries, then the order of power supply is solarpanels first > then battery> then grid. This all happens automatically, so you don't need to worry where the power is coming from.

Why is output lower during the morning or evening than in the middle of the day?

Solar production changes over the day because production is affected by the sun position relative to panel orientation. For north-facing solar modules, you can expect most of the daily generation to occur between 10am and 3pm. For westward facing modules, you can expect a greater proportion of your power between midday and late afternoon.

The solar panels produce power even in low light conditions, like in the morning and in the late afternoon (not during the night), but the amount of power produced will depend on the amount of light on the panels, and the panel temperature. The best condition for maximum power production is actually a very sunny and cold day, as the solar panels produce more power when they are cooler.


What happens at night?

With a grid connected solar system, you are still connected to the electricity grid, so when the sun goes down, any power required will automatically be drawn from the grid as normal. If you have batteries, then they will have charged during the day and then they will discharge during the night to supply power to your house. Once they are flat, you will continue to draw power from the grid.

How does shading affect the amount of solar energy generated?

Solar systems hate shade. This is especially problematic for string inverter systems because a small amount of shade, even on a single panel, can have a dramatic effect on production. Micro inverters eliminate most shading issues because any shade only limits the output of a single panel at a time.

Some shading outside of the hours 9 am – 3 pm is acceptable however it’s always best for solar panels to be installed in locations that don’t get shaded.

For sites with potential shading issues, we always conduct a thorough shading analysis. A roof inspection and analysis with our solar shading software will indicate exactly how much a solar system’s output will be reduced on average over the course of a year. This will ensure we always install your panels in the best location.

Will my solar panels provide me with electricity during a power cut?

This depends on the type of system installed. If you have a standard grid connected system without batteries, then when a power cut occurs, your system will shut down until the grid is back up and running. This is a requirement of the solar installation standards as electricity workers could be electrocuted if you send electricity back to the grid whilst they are working on lines near your property. If you have a hybrid system with batteries, then your system will continue to operate during a power cut. Some battery systems will only supply power until the batteries run flat. Other battery systems can be recharged during a power cut.

How long will my solar power system last?

This depends on the quality of the components in your system.

All solar panels carry a performance guarantee of at least 25 years. Each year they degrade in their ability to prouduce power by around 0.5% each year. After 25 years quality solar panels will still be producing about 85% of what they would have produced when new. Premium panels will still be producing up to 92% of their day-one output.

The quality inverters and racking that we supply have a 10-year warranty, but we expect them to last much longer than this. For example, Enphase micro inverters come with a 10-year warranty as standard, but you can easily purchase an additional warranty which extends coverage to 15, 20, or 25 years. Generally, you can expect the system to run for many decades.

If you have an off grid system, the batteries will be designed for a certain life that is dependent on the daily depth of discharge. We supply quality batteries that typically last for 10-20 years.

Is the system installed by qualified electricians?

Yes, our expert installers are qualified registered electricians with full training for work at height and for all aspects of solar installation work. Your system will be designed by one of our in-house registered Electrical Engineers.

Is there any system maintenance involved?

There is minimal system maintenance required over the life of the system. You may be required to hose down the panels from time to time to remove dirt. The panels will self clean when it rains. We do offer a 12-month post installation check and a 5-year comprehensive system check; however, these are optional.

If I move, can I take my solar panels with me?

Yes, we can remove and then reinstall your solar power system at a new address, provided the roof of the new house is suitable and provided that the Network company approve the reinstallation of your existing inverters. However, you should be aware that the warranties only apply when the solar panels, inverters, and racking remain installed at the original location.

The good news is that the warranties are transferable to a new owner, so most people leave the solar system installed at the original location. The resale value of the house is increased, and they then install a new system on their new house.

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