In part one I concentrated on making sensible choices whilst renovating the house to minimise my power use. If you haven’t read it, now may be a time to look as I’m part way through a journey.
Having achieved much with my renovations, including a living area that didn’t drop below 16 degrees in the depths of winter in Auckland before the heating kicked in the following morning, it was time to consider where to go next.
I’d previously looked at Solar water heating but dismissed it for 4 reasons
- The sun being far away drastically reduced its output in winter as I’d discovered from my DIY solar pool heating. This meant that electric top ups would be needed in winter.
- Our water heating bill was only $750pa due to the timer on the hot water cylinder limiting the cost.
- Solar Water heating needed a building consent and I’m totally against giving any more money than necessary to Len Brown and his wasteful council.
- It needs a licenced plumber to hook it up.
The maths for a 10 year payback in our situation were marginal at best
To reduce our bill further we had two choices, either rewind back in time until before modern life was invented and turn everything off, or look into Solar Panels.
On the face of it, solar power should suit us as we are at home for most of the day, and we have a pool pump that runs whenever the sun is out to heat the pool in summer. The question is how much generation did we need and how much benefit would we get?
Looking at the half hourly smart meter display on the internet gave us a clue, but to really work out what was going on something more accurate was needed.
After a few mistakes along the way I ended up with a product called Open Energy Monitor. This is an open source, make it yourself or buy a kit or buy a made up solution affair from the UK. Anyone that wants to read more can find the website here http://www.openenergymonitor.org/ Be warned this stuff gets technical quite quickly once you go beyond the basics.
The power monitoring is achieved by a combination of plugging an adapter into a wall socket as close as possible to the meter box and either clipping a self adhesive sensor over the flashing light on the smart meter or clipping a current transformer around the incoming supply cable. Sadly the “unique” way Meridian wire their import / export meters up in Auckland means the light isn’t an option so it has to be the CT method.
In NZ / Australia if any of this involves opening an enclosure where live conductors are likely to be exposed such as in the back of a meter board, it needs to be done by a registered electrician. It’s an expensive way of clipping a mainly plastic device around a conductor but there you go.
Once installed Open Energy Monitor allowed me to see what we used, and when we used it.
Armed with the information I could move onto the next bit. Read more »