Saving electricity, saving money, saving the planet?

14 Jun

Another project that I’ve been putting off for a while, but with the wedding out of the way I finally had some free time, so off we go.

Electricity is quite expensive these days, so it makes sense to try and cut down my usage. It’s all too easy to plug something in and forget about it, but all these devices, which on their own may not use a lot, all add up to a substantial amount over the course of a year. Don’t get me wrong, I’m all up for saving the planet, but really, this is just about saving money, my money, probably so I can spend the savings on more gadgets and then ultimately plug them in no doubt. Firstly I bought an owl energy monitor from Argos.

This was the USB version so can I plug in to PC to view live data and usage history, much easier than checking the electric cupboard every time. It’s also battery powered (along with the wireless receiver) and so not adding to the electricity usage!

For reference, a few people might be asking, what are all these Volts, Amps, Watts, kWh’s etc? It’s pretty straight forward, ish, although I’m no expert.

Firstly, electrical power is measured in Watts:

  • Volts * Amps = Watts
  • Watts / Volts = Amps
  • Watts / Amps = Volts

In the UK, your standard home socket will supply somewhere between 220 and 240 Volts.

Still with me? Good. If you’ve ever had to read your electric meter, you’ll know that it’s all measured in kWh, kilowatt Hours. So, if you had something that used 1kW (a 1kW electric fan heater for example), and it was on for an hour, it would use 1kW, if it was on all day (24 hours) that’s 24kWh, just for that item. Obviously the main board in the house (where your meter, and energy monitor if you have one would be) clocks all the electric from every device. So, by the same logic, a 100Watt light bulb on for an hour will use 0.1kWh, because there are 1000W in a kW, hence Kilo. (see here for more information on this subject)

Your energy supplier will bill you based on the number of kWh you use. Now it should be that simple, but there a few more twists. Firstly, if you are on an economy 7 tariff then you will have a different, cheaper rate throughout the night. (There is some very interesting reading on Wikipedia about this, and especially the Radio teleswitch, although I don’t know what will happen to this when the digital switchover takes place, and surely this is wide open to abuse, I need to read up more on this subject). On top of this, you may be billed quarterly, and in my case the first 225kWh is charged at one rate, and anything on top of this is charged at a different, cheaper rate.

I’m currently on the Scottish Power Online Fixed Energy January 2013 Tariff (there are literally hundreds of different tariffs when you search). I called Scottish Power to ask for the exact unit costs etc. You may find them on the rear of your last bill, but at the time of writing I hadn’t yet had my first bill on this new tariff.

Scottish Power Online Fixed Energy January 2013

  • Economy 7 = Yes
  • Day rate (first 225 kWh per quarter, 3 months) = 20.469p/kWh
  • Day rate (after 225kWh per quarter) = 9.938p/kWh
  • Night rate = 5.002p/kWh
  • Night in Summer is classed as 1am – 8am
  • Night in Winter is classed as 12am – 7am
  • Summer = 1st April – 30th September
  • Winter = 1st October – 31st March

Simple eh? Bare in mind that time mentioned above for Economy 7 are for Scottish Power in the West Midlands, they vary also for each region, see here.

We don’t have any storage heaters and so can’t really utilise economy 7 other than perhaps try to run the dishwasher, washing machine and tumble dryer during this period instead.

I also already had a plug in energy meter to measure individual sockets, which is quite handy for more accurate reading of individual pieces of equipment. I found while I was using the Owl, stuff like the fridge and freezer would kick in every so often and make accurate readings of individual items tricky.

Our annual electric bill was for around 6200kWh, which is quite a bit above the national average of 3300kWh (source), in fact almost double!

We should have been fairly efficient, all the lights are on PIR’s (using modified LM12 lamp modules and MS13E2 PIR sensors) and the TV’s etc. all use X10 appliance modules (See My X10 setup) so that nothing is left on standby when it’s not in use.

However, one of the issues with X10 modules, especially the HDM1 (Re-branded LW12’s) micro modules (that fit in the socket behind the light switch) is that they don’t work with energy saving bulbs (see here). But the HDM1, or LW12’s are very easy to retro fit as they are 2 wire design requiring no neutral connection. I bought a couple of PIR’s from eBay, a ceiling mounted and a socket mounted version, both are 3 wire and require a neutral which might make retro fitting quite tricky, I’ll come back to this later once I’ve had a go at installing them. (Update, these now sold, wasn’t worth the hassle) The kitchen currently has 6 50W GU10’s, so when on that’s 300W, which is about the same as a floodlight. The hall and the landing each have a 50W GU10, there’s another 100W

Here are some things I did straight away and the energy savings they made:

  • Turn down kitchen fridge
  • Turn down garage fridge
  • Turn down garage freezer (might have to turn this back up in summer, we will see)
  • Turn kitchen cooker off at wall when not in use
  • Turn off  radio alarm in bedroom (I only use my phone these days anyway)
  • Turn off dishwasher when not in use
  • Turn off tumble dryer and washing machine when not in use
  • Unplug phone charger when not in use
  • Unplug laptop charger when not in use

Once that was all done it was on to the rest of the items in the house, the ones that I kind of knew were hogging the electric. I’ve got a few bits of kit that are on 24/7, my media server for example that records all the TV and looks after all the home automation is in all the time the loft out of the way. I also have another server running Hyper-V which has a few test VM’s on it, along with my Zoneminder VM for constant recording of the hedgehog camera. I also have a couple of wireless access points, the cable modem, my firewall, my 16 port switch, my home-plugs, the TV aerial booster etc.

I could probably spend a fortune replacing everything in the house to be super-efficient, but I think this might be a bit of a false economy, so the for the moment I’m just working on the easy/simple changes that will save us cash. The next phase (which I’m cleverly going to call phase 2) might include more advanced technology, but I think I’ve made a pretty decent start for the moment. We plan to get a new washing machine and tumble dryer, and would be nice if we could set these to run during the economy 7 cheap electric period.