A Little House at No. 18

The ins and outs and inbetweens of building a new house in Little Howard St, Fremantle

The changing play of Solar. Our Energy future.

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Electricity.  It’s not going anywhere soon… Except for everywhere in our lives.  It has featured prominently in the media recently for good reasons, and unfortunately, for bad.  For Littlehouse18 we have been learning quite a lot from our own daily living routine, interesting research and discussions.  But why all the talk?   Things are changing….and fast.

Do you know how much electricity you use per day?  If you do, it’s more than likely that you are pretty energy aware, the cost or consumption is of some concern to you for any number of reasons.  If you don’t, then now is probably a really good time to start taking notice.   Society’s energy landscape is changing, there is no doubt about that.  Uptake of photo voltaic collectors have distorted our electricity networks and there’s a morph of exciting proportion on the horizon!  Just how the next 5 years pans out in WA is currently a little un-certain but one thing is for sure, it won’t look like it does now.

On the 2nd August 2017, we celebrated the first anniversary of a big step towards our own self-sufficiency goal. It’s the first birthday of our 3.8kw solar array and more importantly, our smart energy meter. The next step in our long-term plan is to use this data to help us make decisions on how to reach the self-sufficient goal.

Before we dive too deep into sharing our performance information, I should explain a bit about our consumption.  When we started designing this house about 5 years ago (and hasn’t plenty changed since then!) ,we specified use of energy efficient appliances, aim for 100% led lighting throughout, heating and cooling through “passive” means and use the KNX automation system to assist and control energy consumption.

It’s not anything out of the extra ordinary.   Our house is lit by about 60 warm white LED 24v globes. Brand new to the market in 2013 and being phased out in 2017, our lighting gives a perfect example of how fast technology is evolving. Although they will last us 20 years, they’ll certainly be vintage technology.  (Our advice on emerging technologies is to not wait.  If necessary, commit to using something you know will be superseded within months or you will never commit, and miss out on the more immediate benefits.)   We have 5 highly efficient aeratron fans and two fridges. One small “bar fridge” in the short stay and a much larger Liebherr fridge in the main house.  Two Bosch dishwashers.  Once again, a small one in the short stay and a larger one in the main house.  We run a 65w pond pump when the sun is shining, a very energy efficient Grundfos “Scala2” rainwater pressure pump currently supplying garden reticulation and toilet flushing. We also have two Bosch electric ovens. One small microwave / convection oven combo in the short stay and a larger one in the main kitchen. We have a moderately above average efficient washing machine that seems to be in high demand these days and in the work-shop we often run several large pieces of woodworking machinery and associated dust extractor and vacuum systems.   The oven, dishwasher and fridge appliances were all purchased in 2013 during the early stages of construction.  They were purchased from outside Australia where there was a larger range of more efficient appliances available and we put the effort into shopping for quality and energy efficiency.

But sometimes it’s not what you have, rather than what you don’t have that can make the difference.  We have no air-conditioning, television or desktop PC running which must have some real effect on our energy use and to be totally honest, none of them are missed.

It needs re-iterating that one of the best investments we have ever made was the installation of the Fronius smart energy meter when we installed the solar panels in August 2016.   Fronius Solar.web provides us access to several layers of our Solar production and consumption data.  Our home page shows us our live data.  If you are the type of person who checks the rain radar before hanging out the washing, why wouldn’t you check how much excess wattage you have to play with before you flick the dishwasher or the oven on!   The next layer is the daily graph which updates hourly.  On a sunny day, you can see the neat production curve rising up sharply to the sun’s meridian. Ours are all sloped to the left because our panels are on an east facing roof.   Dig a little deeper into solar.web and you can see monthly and yearly data graphs very neatly displayed.

There is also an inverter efficiencies graph which gives our installer and the manufacturer the ability to monitor and analyze the performance of the system remotely, and even send us an alert if the system begins to operate a little different to usual.

So now that we have been running on grid connected solar for all four of the seasons, we would like to share with you a few of the interesting bits of data that our system has provided.  Over 365 days we have consumed a total of 3,904 units of electricity ( 1 unit = 1kw/h or 1000watts per hour). That’s 10.8 units a day.    Over the same period, we have produced 6,211 units of electricity or an average of 17.2 units per day!

But these numbers don’t make us self-sufficient.  We still consume energy from the grid at night. Over the year we have consumed 1,789 units (or an average of 5.2 units a day) from the grid.  That means while the sun shines we consume the remaining 5.6 units directly from our solar panels. This means we are only 60% percent self-sufficient.   Hence why the habit of consuming power as it is produced is the best.


We could be 100% self-sufficient.  Over the year we learned we have also produced 60% more electricity than we consumed, so it is definitely possible. But how could this be done?

There are several options that are available and we are looking into.  Batteries, of course.  Grid connected or go completely off the grid? Well given the grid supply charge has just jumped from 44c to 86c a day might sway the decision to the latter.  Over 10 years, the $3,150 we would pay just to be connected to the grid could well be better off spent on a bigger battery system offering greater redundancy. To stay connected to the grid we would have to sell an average of 12.3 units of electricity a day at 7c each to just offset the service fee.

Alternatively, new technology being developed by “Power Ledger” in WA is promising us we can sell our surplus electricity to our neighbour at a much more attractive price than the existing 7c wholesale feed in price.  Do we then adorn our roof completely with solar panels as a method of financial offset or investment? Might not be that silly. This is also good because my neighbour will love cheaper and cleaner electricity from us (rather than the power station) and we can recover some of the daily cost of being connected to the grid.  We become a prosumer, that is a producer and a consumer.  But this solution doesn’t absolve us from the requirement to have batteries to cover our night time consumption.    Here is a link to Power Ledger white paper


Our Solar installation and smart energy metering cost us $7650 in August 2016.  Over the last 12 months it has earned or saved us $870 giving our system a payback of 8.8 years.

Our goal of one day becoming self-sufficient (in electricity use) was a fairly far-fetched goal in 2012. To an extent, the self-sufficient terms have also changed to be running cost neutral as well.  Imagine creating and storing enough electricity to look after yourself but be able to sell excess to the community around you.

Luckily for us, the target which we set ourselves 5 years ago is being moved ever closer with developing and emerging innovations. But the luck doesn’t stop there, this target of becoming self-sufficient appears to be moving closer to us all.


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