Homeowners – Ask these questions before buying a solar system

These are questions home owners should be asking the solar company before buying a solar system for their homes or buildings.

Home owners interested in having a solar system on the roof gets the following from various solar companies.

“The solar system is the cheapest price with Bloomberg tier 1 panels, 10 year warranty on inverter and 10 year workmanship”

How does the homeowner compare various quotes?

Well, solar system failure is due to poor quality of equipment, poor quality of installation and the system supplier no longer in business to rectify the failure.

From experience, there is 3 parts that make up a solar system.

  1. Solar panels and inverter, the quality have improved a lot hence it is easy to get a quote that places more emphasis on solar panel and inverter quality.
  2. Components like DC isolator, cables, conduits etc. There is various levels of quality with these products. How does the homeowner know that they getting good quality products. Well they don’t know, and even they are given datasheets, it will be hard to gauge the quality.
  3. This is most critical. The quality of the install. Poor workmanship is the single biggest failure of solar systems.
  • poor clamping of panels,
  • cables touching the roof surface,
  • poor earthing of panels,
  • dissimilar metals,
  • cables not in HD or UV rated conduits,
  • feet spacing not as per wind loading certificate,
  • panel clamping not as per solar panel installation manual,
  • poor panel handling causing abrasion on glass,
  • panels installed in shaded area,
  • inverter location is poor,
  • cable route is poor,
  • poor termination of DC isolators
  • cable is undersized.
  • There is lot more in the list.

The reality being, there is no way a homeowner knows how good or poor the quality of the install will be.

The biggest cost of the solar system isn’t the purchase price, but the cost to repair if the solar company is no longer in business.

7 Questions to ask the solar company and get answers in writing.

Q1 – How long has the company been operational? Minimum 4 years ABN registration is a good start.

Q2 – Check if the company has its own electrical contractor’s license? Get a copy

Q3 – What is the system performance, potential savings with the electricity bill and energy yield of the system? A solar company selling you a solution rather than just products will supply this information.

Q4 – What is the energy yield guarantee? A solar company selling you a solar system can guarantee its output based on Science and weather data.

Q5 – What is the guarantee on the potential savings with the reduction in the electricity bill? A solar company should guarantee and make up for any shortfall with the promised savings.

Q6 – How will the solar company monitor the system during the workmanship period? As the solar company is providing workmanship, they need to ensure the uptime of the solar system. It should not be the responsibility of the homeowner to inform the solar company of any fault or failure.

Q7 – What is the response time for the company to track the fault and visit the site to rectify the fault? Faults happen, a good solar company should be clear on how they will provide workmanship services and quickly attend to the site.


In the residential space, there are 2 types of solar companies.

  1. First, a solar company just trying to sell you a solar system. They will emphasize that the solar panel is Bloomberg tier 1 listed hence is of high quality, the inverter comes with a 10 year warranty and the company itself will provide a 5 or 10 year workmanship warranty on the whole system. On top of that, they can beat any competitor’s price. Typically, this company is only selling you a solar system and not a solution to reduce your electricity bill. It is evident these companies is to sell cheap systems in high volume (at lower margins of course) and a right time (when poor installed systems start failing) the close the company, exit the solar industry or change the company name etc.
  2. Or, a solar company that has sustained growth, has been in the solar industry for a longer period of time, offers competitive price and presents a solution to a client. They will always have time to answer the questions.

Pricing rule of thumb

  • Poor quality solar system price for a 6.6kW solar panels with a 5kW inverter is under $4,000
  • Good quality solar system price for a 6.6kW solar panels with a 5kW inverter is over $4,000
  • What is the cost of replacing a faulty inverter under the manufacturer product warranty? $300.00 (2 trips by the electrician)
  • What is the cost of replacing the inverter NOT under the manufacturer product warranty? $1,500 – $2,500 as a minimum
  • What is the cost of replacing a 2kW inverter installed 6 years ago and not covered by the product warranty? $1200 or replace with a new system.

Expectation with the solar system

The life of the solar panels is more then 25 years.

The life of the inverters is 11-13 years hence require one change in the 25 year system duration.

The payback on the system based on the system cost and savings should be 3-5 years.

The aim is to recover the money spent within 3-5 years then the system generates income for over 22 years.

I provide free advice to many residential and commercial clients seeking answers or require clarifications on solar because of confusion from various sales pitch.

Happy to help.

Things to check when buying solar panels for your house?

The deployment of solar panels in residential sector is at a all time high with good system pricing due to government incentive, low interest finance, market competition and high electricity tariffs. With the solar retailers hunting for any solar sales, price war and sneaky marketing require attention.

How to make the right decision with solar.

You, the customer may feel that it is a simple process of contacting some solar companies for quotes and in return, you get bombarded with multiple quotes of various system sizes, different solar panels all claiming to be the best and a large percentage decrease in the electricity bill. This leads to confusion.

Reading the following article, one asks the question, if all solar panels are tested to the international standard, why are there failures?


Well, solar panel failure is one of many issues that can occur. Ideally you want to pay for a solar system that will operate for 25 years without any major failure and will reduce the electricity bill as promised.

Based on my 20 years of experience in the solar industry, being part of many project deliveries, quality audit and engineering system for clients, the following is my guidance;

Solar panels : The quality of the solar panels in the market have been good in the last couple of years, with most solar companies offering Bloomberg tier 1 listed panels which is a manufacturers bankable qualification process. For standard 60 cell crystalline solar panels rating, the 280W is the point of demarcation, any panels lower then 280W uses older cells with lower efficiency. My recommendation is to go for 280W or higher panel rating.

Inverters : There are 2 groups of inverters available in the market. My trusted brands are ABB, SMA, Huawei, Fronius, Enphase and Solaredge. These are some of the globally recognized high performing inverters that can last an average of 12 years in the Australian climate. Then there are other inverters brands classed as entry level. These inverters are cheaper because they may have any combination of lower cost of manufacture, cheaper electronic components, limited R&D budget, lower efficiency & performance with wear & tear of components, basic warranty coverage, less testing during manufacture and less features etc. My recommendation is the trusted brand of inverters with a 10 year full warranty on parts and labor. You may also find a 5+5 year warranty which is first 5 years full replacement warranty the the next 5 years does not cover labor cost for replacement.

System design: The term AC:DC ratio represents the inverter power rating over the total solar panel power rating. Typical example being a 6.6kW solar system with a 5kW inverter. Solar companies are simply maximising the amount of solar panels that can be connected and still be above the minimum of 75% ratio to claim the government incentive (5/6.6= 75.7%). This low ratio can cause restrictions to solar energy generation in the summer months (eg. solar capability is 6.6kW but the inverter will only allow 5kW production). My recommendation is to have a AC:DC ratio above 85%.

Product Warranty claim: There are 2 product  warranties (solar panels, inverter) that is very important to consider. Standard solar panel comes with a 10-12 year product warranty and a 25 year performance warranty. This is a standard warranty that all solar companies will present. You also need to know what will be the warranty process if the solar panel fails and the solar manufacturer is no longer manufacturing. Good solar manufacturers will have in place a third party insurance process that will guarantee that the warranty is honored. With the inverters, a 10 year full warranty means that you will not pay for the replacement if the inverter fails within 10 years. But you should also be mindful that many manufacturers disappear hence investing in a good inverter and manufacturer makes sense. Some manufacturers offer a 5+5 year warranty whereby if the inverter fails in year 6, then the manufacturer only supplies while you have to arrange an installer to install it. A 5kW inverter replacement cost outside its warranty period can be $1,500.00 or more.

Workmanship warranty: This is something not discussed during the sales process but is most important. Poor workmanship can contribute to a much higher failure rate of the solar system.  Lets face it, there are good installers who have the experience and passion to install a system at its best. Then there are installers who will cut corners to finish the install within a specified time because any work outside the contracted time means that they will lose money. Poor workmanship can be bad electrical termination, dodgy equipment installation and carelessness on the roof leading to water leakages. The industry standard workmanship warranty is 5 years and some may offer 10 years. Workmanship warranty means nothing if the solar company goes out of business (common issue) and  in the case of a fault can cost you almost almost $500 to get an electrician onsite to only diagnose a fault and additional cost to repair or replace equipment. My recommendation is to research on the solar company, see reviews on google & facebook, check ABN details for operational time (minimum 3 years), Clean Energy Council retailer list.

System performance: The whole reason why solar panels are installed is to reduce the electricity bill. The solar companies take the daily energy use data (eg 28kWh/day) from the electricity bill, Quickly decide how much energy is consumed during the day (eg. “someone at home” means 60% x 28kWh = 16.8kWh used during the day) and this based on a 4 sun-peak hours (16.8kWh/4) means a 4kW system with the obvious upsell to 5kW or even 6.6kW. You already know that solar cannot provide energy in the night hence a battery addition in the future is possible so investing in a slightly bigger solar system size isn’t a bad idea. But most important of all is to understand the economics. The solar system is an investment and hence there shall be a return. The solar company needs to provide a very clear and accurate solar panel layout drawings, monthly energy yield data, estimated decrease in  the electricity bill for each of the month and the payback period. A good solar company will invest its time in giving you a proposal with all these data rather then giving you just a price. My recommendation is to get a formal quotation with all energy modelling and economic modelling details. Payback period shall not be more then 4 years. Once the solar system is installed and you receive your electricity bill, get the solar company to prove that the system performance based on the reduction on the new electricity bill is validated.

System monitoring: Monitoring of the system is very important as this gives you eyes on the system. Some monitoring system records the solar energy produced , compares it with the weather data of the location and informs you on a daily basis how the system is performing. You can also record the load data hence seeing the bigger picture of the whole energy profile which will give you all the information on the requirement of the batteries. This data is also important when dealing with the solar company who provided the system and is responsible for the energy generation based on their own modelling. My recommendation is that a monitoring system eg Solar analytics is a very important equipment that can improve the system performance and better savings. On average a third party monitoring system can cost $500 but can easily pay itself back within the first year.

Remember: When you are buying a solar system for your house, included in the cost are solar panels, inverter, electrical materials, workmanship, warranties, system performance, reliability and assurance.

A solar company achieves a cheap price by presenting “best of the worst” solar panels and inverter, poor installation, no time on comprehensive proposal, no time on economic modelling, no intentions on upholding warranty and doesn’t intend to be operational in the market long term.

The above information all clearly presented by the solar company means that they have taken time to present a site specific proposal rather then a generic price quotation.

How expensive is a cheap solar inverter

4 years ago, a Mr Jones, decided to get solar panels installed on his roof hence contacted a few solar companies for quotations.

The prices of the 3kW system ranged from $2,500 to $4,000.

Now Mr Jones is a confused man with the different pricing and all companies claiming to have the best quality product. The clear winner was the cheapest price (of course!!) and upon enquiring, the salesman assured that this was their biggest seller, the price is cheaper because the solar inverter is not as expensive as the European made inverters but gave assurance that its performance is the same and it came with a 10 year warranty.

So in 2012, Mr Jones brought a 3kW system for $2,500 and thought he saved up to $1,500.

Late 2015, Mr Jones contacted me regarding his solar PV system (a friend recommended him to me). He mentioned that his system stopped working 1 year ago and the solar company who sold the system is out of business now, and he has no contact details of the installer.

To help Mr Jones, I visited the site with my electrician who checked on the system and later sent a repair quotation to him. Mr Jones was shocked with the repair cost. It was a crazy $3,400.

Well at this price, Mr Jones could purchase a brand new 2kW-3kW system but the existing faulty system needs to remain on the roof (STC t & c’s).

Of course Mr Jones wanted an explanation on why the repair cost was so high because his initial understanding was that only the inverter had to be changed.

Well, the inverter manufacturer is also no longer in business now so the 10 year inverter product warranty is of no use. The same make and model of the transformer based inverter cannot be sourced so another brand inverter needs to be installed.

Some key points during the inspections were;

The inverter is OFF, possibly component failure and would not switch ON with DC power supply;
The solar panel string voltage (open circuit) was in the acceptable range (brand of solar panel is a reputable manufacturer) so no panel fault identified;
The installation quality was very poor with cable management and all the panel leads and string cables were loose and touching the roof;
This install was done before the AS5033.2012 Standards was implemented;

The following was the cost breakdown;

$1,400 is the inverter cost – this is a European made inverter from a manufacturer that is top 3 in the global market.

$200 is for new DC isolators next to the inverter and on the roof, this system was installed before the AS5033.2012 was released hence there was no DC Isolator on the roof and the disconnectors next to the inverter was the polarised circuit breakers which cannot be used under the new standard.

$300 is for the heavy duty conduit under the roof. This requirement was not mandatory before the AS5033.2012 standards release.

$500 for the new mounting system on the roof. The electrician has to tidy up the loose solar panel cable leads hence needs to unbolt the clamps to lift the panels to manage the cables. Because the bolts & nuts of the clamps have aged, there is corrosion and a risk that it will be hard to unscrew the nuts from the bolts, and once unscrewed, the T-bolt thread and the nuts can be damaged. It’s hard to find new matching t-bolts and still have the mounting system compliant with AS1170 wind loading as the mounting system initially used does not have a brand labels.

Overall the electrician has to complete repair works and take ownership of the whole install hence becomes responsible for the whole system.

Interesting Dilemma!!!

Well, for the records, Mr Jones chose to pay the $3,400 and get the repair done instead of purchasing another system.

In trying to save $1,500 by compromising on the quality of the system, he ended up spending a total of $5,900 for a 3kW system.

eArche solar panel opens up new markets and broader applications for solar installers

eArche is a new and innovative solar panel now available to the Australian market.

Conventional solar panels use silicon cells with a glass and aluminium encapsulation. eArche panels uses the same silicon cells, but without glass and aluminium.

“Sun King” returns with ultralight, flexible PV to reshape solar market

Why will eArche panels suit your application

1. Flexibility and Suitability – the panels can be installed on a flat or curved roof. There are various installation methods from as simple as using silicone adhesive bonding to multiple mounting rail systems. Whether the roof is penetrative or non-penetrative, concrete, insulated panels, light weight, glass or simply for aesthetics reasons, we have mounting systems to suit your requirements.

2. Industry standard warranty – 10 years workmanship warranty, 25 years performance warranty. The composite material used that replaces glass, is a proven material used in the aircraft windows for decades;

3. Lightweight – 65% lighter than conventional panels. eArche 325W panel weighs 7.7kg.

Currently, an installer can move one conventional 325W panels which is 26 kg. Now replace that with 4 x eArche panels and suddenly, you are moving 1.3kW at once;

4. Weight loading on the roof – Have you comes across a job where the client didn’t pursue with solar because the roof could not handle the weight loading? A 100kW of conventional panels on the rooftop, that’s more than 8 tonnes of weight!. The equivalent eArche system will only be 2 tonnes. Conventional panels have a weight loading of 15-20kg/sqm. eArche panels are under ~4kg/sqm.

5. Packaging – the thickness of the eArche panel is only 5mm when compared with the 35mm conventional panel. A standard 2m x 1m pallet can hold 80 x 325W eArche panels. Now that’s 26kW on a pallet that sits on a solar installer’s box trailer. Compare that with conventional panels, its 7.475kW (23 x 325W conventional panels);

6. Forget 2 different sized panels (60 cell and 72 cell), we have 24 different sizes approved with the Clean Energy Council.

7. System performance – Same conventional silicon cells are used hence there is no power degradation decrease in the energy yield. The daily performance of eArche panel is similar to the conventional panels;

8. Bloomberg New Energy Finance recognised eArche as one of the most advanced product in the June 2017 report.

eArche solar panels performed at 87% performance ratio last September

eArche is a new and innovative solar panel launched into the global market by Dr Zhengrong Shi. It has passed international and local standards same as conventional panels.

How good is this panel, Let’s compare…….

A 72 cell conventional 325W solar panel, it is made up of silicon cells, tempered glass, anodised aluminium frames and weights no less than 22Kg.

Heavy, bulky, needs 2 installers to move the panel and each 40ft container can only fit 185kW.

Now use the same high efficiency silicon cells, replace glass with a composite material, remove the 35mm thick aluminium rails, the panel now weighs less than 7kg.

Lightweight and thin, now you can fit 600kW in a 40ft container and the same 2 installers can lift and move at-least 5 panels at once, that’s 1.625kW.

A composite material to replace glass. What about the product warranty?

This composite material is a proven material from the aviation industry used in the windows. The eArche panels has passed all IEC tests through the testing provider VDE. eArche panels have the same workmanship (10 years) and performance warranty (25 years) as the conventional panels.

Glass has a high refractive index hence causes light refraction and reflection which causes ~5% loss of light. The composite material on the eArche panels have much lower refractive index hence the light loss is much lower.

With various mounting methods, eArche can be installed much closer to the roof surface.

With conventional panels, due to the glass top, heat from the cells could only escape from the bottom hence there was always a gap between the panel and the roof surface for natural ventilation.

With eArche panels, the cooling of the cells occur both from the top side and the bottom hence silicon cells dissipate heat quicker and hence performs better.

Recently recorded energy yield data at one of the eArche sites in Sydney.

In the month of September when the optimum inclination of the solar panels is ~20°, eArche panels was at 5°.

There were zero rainy days in September, 21 days was above 20°C ambient temperature with 10 days well over 25°C.

The system size was 25.2kW. The irradiance recorded for 31 days was 163 kWh/m² which is ~5.26 sun peak hours.

The eArche system generated 3229kWh for the month as measured with a Class 1 meter.

The performance ratio was calculated to be 87%.

The ~13% loss accounts for temperature losses, soiling, voltage drop on cables, inverter efficiency and all losses that the PV system face in the field.

The monthly eArche performance ratio has been in the range ~ 85% – 94% for the last 8 months.

In addition to install on the normal roofs, EArche can be applied to the places whether:

· the roof purlins is not sized to take 15kg/m² of weight loading;

· the roof has a curve;

· aesthetics requirement or limited roof space;

· Panels don’t have to be installed 120mm above the roof material.

Happy to share more details and data…..