January 26th, 2011 by Kevin Leave a reply »

You know civilization is advancing at warp speed when your toaster wakes you up, tells you the time in Tokyo and displays the state of play, via twitter pic, of the carcinogised crispiness of your optimised bread product.

Can-openers with mains leads, tooth brushes with massage settings, so much choice but so few sockets – what’s a 21st century eco-warrior to make of it all?

Well fear not fellow waste watchers, for here is one wifi-display-with-a-mains-lead to rule them all. What’s more it’s free to use and it’ll save many times its weight in equivalent CO2 emissions, once that is, it’s finished saving YOU money on YOUR electricity bill. All hail – the Current Cost Meter.

What does it do? It displays the energy currently being consumed in your home and how much that energy is costing you. How does it do it? Short answer – magic.

I found it’s good for two things – one, gaining an understanding of what (or who) the heavy energy users are in your home, and two, finding those appliances that don’t use a lot but are doing it constantly. Our cooker’s got a timer and displays the time, it’s uses about 10W to do that which doesn’t sound a lot, but still works out at more than 80kWhrs or £10 over the year. (Based on 12pence per unit)

When I started we had an overnight background power use of about 75W (equating to around £75/annum). By deciding what we do and don’t need on, and juggling things to separate what we want to turn off easily, we’ve  got that down to under 25W, or £50 in the bank.

Basically, if it draws a lot of power you don’t want it on for long, and if it’s on for a long time you want the version that draws the least power. What the Current Cost Meter does so well is to convert all that into money so you can make an informed choice.

It’s easy to set up. Clip the sensor (black and red thing at the bottom of the pic) around the incoming mains cable, and plug that into the transmitter (the black box at the top). Plug the display unit into a mains socket and it’ll probably start working straight away. If not a simple “mating” procedure is required to couple the wireless transmitter to the display by pressing a red button.

There are a couple of little niggles. The display needs to be plugged into a wall socket, so moving around the house with it, turning things on and off as you go, isn’t as easy as it might be. The display updates every two or three seconds which sometimes means the change due to the light you just turned off is obliterated by the fridge cutting in, but you soon get the hang of it.

These aren’t show stoppers by any means, and with energy costs on the rise this will be time very well spent.

Available to borrow for two weeks, in exchange for a £10 deposit, get your Current Cost Meter from the Town Centre Shop,  3 Welch Way, Witney, OX28 6JH, opening times: Mon-Thu 9-5.30 and Friday 9-5.



  1. Sally says:

    I love my current cost meter. It really does make a big difference to the way you look at power usage, it is so much more immediate and feels instantly rewarding when you get your base usage down.
    Both my husband & son use it as well because it is “a gadget”, inspired him to rewire our under kitchen cabinet lights so we could switch to low energy LEDs.

  2. Kevin says:

    Ah! Cabinet lights – those 12V G4 bulbed 20W recessed things?

    I’ve been looking into ours, discovered that the supply from the transformer isn’t compatible with the LED versions. Looks like a relatively expensive upgrade, but it then it wouldn’t matter if we left them on most of the evening because they’re only a couple of Watts each. I’d be interested to know what Hubby got and where from?

    Did you get your cost meter as part of a tariff with a supplier or seperately?

  3. Sally says:

    I got given my cost meter a couple of years ago as a Xmas present – closest model today is Owl CM119 – there are much cheaper ones available now, as well as free offers such as the article above. I do think it’s brilliant – changed alot of our behaviour. From reminding you when you’ve left lights/appliances on to changing how you use your big power guzzling appliances too.
    The other gadgets that I think are worth investing in are the standby plug sockets that you use with a remote control. Make it much easier (& therefore much more likely you will do it) to switch everything in a room off at the wall switch.

  4. Sally says:

    Kitchen cabinet lights are a long complicated story!
    The kitchen, that Steve installed a couple of years before we were flooded in 2007, had 4 slimline fluorescent link lights fixed to the underneath of the wall cupboards. These were hidden from view by a wooden lip around the edge of the cupboard. Although not that low energy (20w & 30w)considerable better than the 10 recessed tungsten spots in the ceiling the are our only other form of lighting in the kitchen!!
    When we had the new kitchen after being flooded – I decided I liked the triangular metal under-cabinet lights now available (with halogen bulbs!) much to the irritation of Steve who thought we should stick with the fluorescents. I got my way (of course!) but after acquiring the Owl meter – very shocked at how much power they used & we also needed to replace the bulbs at least every 6 weeks.
    The electrician who had installed them had made a real mess of the job and Steve felt they needed rewiring any rate & found a fairly cheap option for new transformers (LED drivers £5 on ebay) the LED bulbs producing 80 lumens against 300 lumens that the halogens were. However to be honest the LED option that fits with what we have as fittings doesn’t really produce enough high quality light, although they do look good. So he’s now put back 2 of the fluorescents (that he removed when the kitchen was gutted after we were flooded) to supplement! His longer term plan is to eventually change to a more expensive larger mains powered LEDs/fluorescent triangular light system. By the way the best & most simple option we came up with was to have a small table lamp with low energy bulb in one corner, which provides nice cosy lighting & we only use the under cabinets when we need brighter light to work with!

    Here are the the links:

    LED lights we used:
    LED Driver Transformer we used:
    This company sells selection (under Kitchen Lighting) of the more expensive Mains powered LED triangular fittings that we’re planning to upgrade to as well as the fluorescent link lights that we had in the past:

  5. Kevin says:

    Thanks Sally – those will be very useful. Planning a lighting blog as part of a series on Eco-Renovation.

  6. J-P says:

    We have one of the older versions of the current cost meter: the white, blocky one. Rather neatly, it has a serial-to-USB cable that I’ve managed to get some data out of into our computer. A couple of links describing what other people have done:


    Anyway, if anyone here has a low-power home computer running all the time, and knows any Python programming at all, then this program might be of use.

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