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.