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These are the main reasons why homeowners and companies install PV Solar;

  • To save on their power bills

  • To reduce carbon emissions

  • To be more independent and have some control over their power needs

So why is it so hard to make a decision on installing it? Well some reasons are;

  • It is expensive, typically $4000 to $5000 for a quality 2.5kw system--this is a recommended entry level size. Systems below 2.5kw have long paybacks.

  • It adds complexity to your household, just like a pool or large air-con system.

  • It requires ongoing maintenance and monitoring.

  • There can be great uncertainty as to the performance of the system once it is installed, unless of course your system is supplied by Tenergy Australia.



Making sense of the  PV solar market in order to make a decision on what to buy and who from is bewildering even for those with moderate technical knowledge. We are bombarded with TV adds offering 5kw systems for $4990, and tele marketers are calling from Bombay every 2nd day. Most consumers are wise enough to realise the folly of going with any of those offers--but it is tempting.


RESIDENTIAL SYSTEMS--what should homeowners consider?

The recommended decision paths for homeowners are as follows;


1) If you care for the environment and the future of mankind there is no economic analysis required. Every system will reduce carbon dioxide emissions. But you need to know that the payback period can be as long as 12 years for a small high quality 1.5kw system or as short as 5 to 6 years for a much larger 5 to 6kw system.

2) You should size the system to meet your normal summer time consumption during the day. If the system is sized at say 125% or even up to 150% of your normal Summer daytime demand, then that will provide good coverage for the Autumn and Spring time period as well.

3) A system sized as above will also be suitable for a medium sized battery storage system to be installed in the future. Batteries are too expensive now but should be more affordable by late 2017 or 2018. Keep that in mind. As at Jan 2017 the cost of storing 1kwhr of energy ranges between 45c to $1.50. Until that cost comes down to 25c then the economics for most households will not be attractive.


1) If you ONLY want to reduce your power cost and with the best payback period possible then you need a thorough economic analysis carried out to provide the best option for you. Refer to my PV Solar page for this process.

2) You need to advise the maximum outlay you can afford. But note that the vast majority of systems will have a return on investment (ROI) greater than the interest obtained by keeping your money in a bank deposit account.

3) You need to accept that the payback period will range between 5 years to 10 years, typically.

4) You need to accept that ongoing maintenance expenditure is needed.

5) You need to understand that exporting power into the grid will not give a sensible return on your investment. At best this will only reduce some of your cost for producing that power, certainly in Victoria where the Feed in Tarif is only 6c/Kwhr versus your cost of production of between 8c to 12c, typically.

6) If your cost consciousness is for the long haul, then PV solar should be seen as one element of reducing your electricity demand from the grid. Reducing your demand by using LED lighting, insulation, reverse cycle heating/cooling and double glazing should all be part of your long term strategy to reduce your costs.


The systems designed by Tenergy need monitoring via an internet connection. Therefore your house needs a broadband or cable connection, with Wi-Fi or LAN cable available for the system. Once you have decided to go with Tenergy Australia then the process is as follows:

  1. Quote and Design: Tenergy will provide a quote and design to meet your needs. The quote will provide an economic analysis, if you provide historical usage and billing data. You need to then sign and provide a deposit.

  2. Installation: The materials are ordered and the electrical contractor is arranged for the installation day.

  3. Commissioning: The system is usually commissioned and fully functioning in one day. Sometimes the Enphase communications can take two or more days to finalise, depending on internet connections etc.

  4. Final Invoice: When the system is operating and the paperwork completed with your electricity supplier then the final invoice will be submitted.

This handy sheet, Taking the Plunge to PV Solar,  will help explain things in more detail.