How to choose solar and batteries for low bills living

"Congratulations on going for solar," I said to the Low Bills Living Course folk last July sitting around the table at Sydney's Sustainable House and to those joining us by Skype from Victoria, Canberra and by phone from Oberon, NSW.

Here are my suggestions, comments made during the conversation.  These are the fruits of some lessons over the last 21 years of living with solar, and intended to help you be clear about what you need, what you buy, and what you get.

(See note below about a battery product and an installation company I do NOT recommend.)

  • The key thing: you are not really buying the ‘bits’, you are buying a promised amount of power.  
  • Until you monitor the performance of the ‘bits’ you don’t know if they are producing the power you were promised;
  • The panels, inverter or batteries may not produce the promised amount of power because of; poor design (ie the inverter, battery, panels are unsuited to each other); poor product; poor installation;
  • To quantify the key goal of the purchase - the amount of daily power you are buying - ask for a graph showing the amount of power the system is designed and specified to produce over 12 months.  Without this graph you are paying on trust, not data, and have reduced consumer rights;
  • Installers with a national or multi-state coverage may sometimes buy products cheaper than smaller installers and may have higher work and design quality, but not always;
  • To know what power is produced monitor the solar output and house demand, and, preferably, use a third party monitor as well as any which come with the systems;
  • Most profit for installers is in the installation, not the sale of the ‘bits’;
  • About five years ago Ausgrid  surveyed 8,000 NSW solar houses; over 4,000 were not producing the promised amount of power and the owners did not know it as they had no monitoring system;
  • A monitoring system(s) I recommend is an integrated one like, Wattwatchers / Solar Analytics;
  • Do not buy anything without first getting quotes with a 12 months production graph which is, preferably, overlaid over your anticipated daily average electricity use;
  • A list of accredited installers is here;
  • A checklist of ‘must have’s’ produced by the solar industry is attached to guide you in selecting an installer and products; get all boxes ticked ‘yes’, or don’t buy;
  • Get your daily use down as much as possible to make your investment in solar more efficient, productive (see, Sustainable House -
  • Now, to your products: a good product can be, and often is, poorly installed;
  • Hold back at least 10% payment until you know the system has been installed properly and is producing the promised amount of power – get at least one week generation/use data;
  • Get proof the solar panels are a ‘Tier One’ product;
  • Compare battery prices here;
  • See notes, How to choose an installer checklist by Brian England of Self Sufficiency Supplies for the Solar Energy Industries Association
  • See the design and three options for a house  in Sydney by Off Grid Energy (Damien Griffiths)
  • Battery safety, guidelines


How to get the most out of your investment in solar, batteries

Get your daily energy use as low as you can by:

·      Energy efficient appliances, fittings, materials, design

·      Prioritise getting the most energy-hungry appliance(s) to be the most energy efficient eg aim for a fridge that uses less than 700 watts a day and which is ventilated / cooled 24/7 by cold air below it – it’s on 24/7 and can be the biggest single energy-using appliance

The less energy used each day, the less money you spend on your panels, batteries because you will need fewer panels and / or batteries to meet your energy use.

Here’s a quick (incomplete) savings guide from the NSW EPA

Then, there’s food . . .

. . . the growing, production, transport and waste of food uses 20 to 40 times more energy than does a low bills household.

Solution: grow and buy local food; see my book, Sustainable Food.

I do NOT recommend . . .

Following unsatisfactory design (panels, inverter and batteries are incompatible), installation (cables crumbling apart in 2 and 1/2 years, leaking roof, etc) and significant system under-performance (46% of promised amount of power), I do NOT recommend . . .

. . . this battery product:  Alpha-ess, or

. . . these installers:  Australia Wide Solar.

The systems are being fully removed and replaced.  For data analysis see here.

Buyer beware.

The next Low Bills Living Course starts 23 September and is on these days: 23, 24 September, and 7, 8 October, 2017.

Book here.  Maximum of 9 places.  Two scholarships available.