Power Savings


Inspired by another thread which brought up the concept of power draw from Qi chargers and just how efficient they might (or might not) be I started wondering what, if anything, people do to reduce their power draw.

Do you do anything to actively reduce your power use?
Select products based on their power efficiency?
Installed solar panels?
Turn off power points to cut out stand by power?
Have some fancy tech that does something?

I’m interested in doing things, like shiny toys, automation, but ultimately I’m full of power-hungry equipment and while I like the idea of being power efficient… I’m also lazy and like my tech to be on when I want it without getting off the lounge.

I spend way too much time working out if something to make me more efficient costs money I’m going to work out if it’s worth investing in or not for my situation.

For example (and there is a spreadsheet that allows you to adjust all the parameters):

You can pay more/less for given bulbs and power costs may be different (and are going up) but an upfront investment in LED does save you money over a short enough space of time to make it worthwhile… but more importantly I like the brighter whiter light LED provides. So LED everything for me!

Solar panels on the other hand really are a long-term investment, my last calculations worked out (and backed by Choice cals I might add) that solar is a 10-year payback. It’s getting better, but there are a whole heap of caveats in there too… like if you’re not actively using the power you’re harvesting, either directly or later through the use of batteries (which add to the cost), it’s quickly not financially worth it for the average punter. In most cases, you’re probably better off putting the money into your mortgage than putting up solar panels.

As you may have noticed, for me it’s all about the financial aspects at the moment.

If I was building a new house I’d love to get all fancy about things and have smart switches on every power point so you could automate turning things on/off from a central control panel at a ‘per power point’ level. Relays + IFTTT config make it all very possible, although it requires having things wired up in a way which supports it, not something that’s easy to retrofit. Although these things are getting more and more affordable. Low voltage LED lighting throughout without having any 240V running everywhere. Again controllable at a per light level (or at least per room).

I’m sure there are lots more, but I’m interested in hearing about your approach?


You’d be better off building a holiday bunker or something to live in on a property and design that to be live as much off the grid as possible. Building houses and making changes cost big dollars unfortunately during that construction and pre-construction phases.


I work in the solar industry, though specialise in off grid systems. I don’t know when you last researched this, but most people I trust in the industry are talking payback times for straight grid connect around 5 years now. For an asset that will last 25 years, that is a pretty good investment. Don’t forget that you’re saving money straight away. It’s not somewhere over the rainbow. SolarChoice has a calculator here if you’re interested. Just choose a good installer. Don’t go cheapo.

For lots of reasons, this is not as attractive as it seems at first blush. ELV (under 100V more or less) wiring needs to be larger, so more copper. DC switchgear is crazy expensive because it’s low volume, plus switching DC is actually really difficult due to arcing, so the switches are more complex. That’s two of the reasons we use 240VAC - smaller cables and easy switching because AC arcs are self-extinguishing.

We used to do DC wiring for people with off grid systems but we haven’t recommended it for a long time now.


Part of the issue is the cosmetics of having ugly solar panels on the roof - if the Tesla roof tiles were more available and cheaper, then I think more people would use them with the Powerwall or similar battery.


After moving to a new place… first thing we did was get solar installed. It makes a big difference to our usage and bills.

You can check out the pvoutput data I am exporting and plotting…



What happened in November? Did you have a fault?


Mid aug to mid november… the wifi on the solar invertor was off my network. So my RPi couldn’t see it to pull metrics… took me a while to notice it and fix it, as it has to be done when sun is up :slight_smile: