Whole-house electricity monitor

As I wrote previously, I’ve been keeping tabs on how much electricity I use.  Last week I got a whole-house electricity monitor called an OWL from natural collection and have been playing around with it.  It’s surprising how surprising the results are, if you see what I mean.  I know that switching on the kettle uses more electricity, but I was a bit taken aback at how much more.

The same goes for the oven although it makes it very easy to see when it’s up to temperature!  I’ve put in the amount that Ecotricity charge me per kWh (10.65p, although the OWL only allows tenths of a penny so it thinks it’s 10.7p).  With the oven on it shoots up to over 30p/hour, and when it’s up to temperature it goes right back down to about 5p/hour.

The lowest I’ve seen it yet is 1.2p/hour (at night), which is about 115W.  I’m not sure what the accuracy of the measurement is.  It does seem to drift about in a 30W range (i.e. by about 0.3p/hour), but perhaps there is some appliance doing that in standby for some reason.





9 responses to “Whole-house electricity monitor”

  1. Scott Williams avatar

    Whoa! That’s a great idea. I’m sure many are looking to save money wherever they can. This sounds like it could be a good investment.

  2. tim avatar

    Yes. When I first saw these types of devices they were selling for over £80, but this one cost me £35. Still a bit steep perhaps but it may lead to electricity bill savings depending on how much electricity you currently waste. 🙂

    Having the display show you readings in terms of money is quite compelling…

  3. covex avatar

    This CO2 calculation.. what the heck? Ok otherwise this is clip ammeter, maybe with calculator for a price right? But I do not understand how it can measure what you waste? If your oven is running is it a wasted energy? I hope not.. you should heat up some food, not just the oven. 🙂

  4. tim avatar

    Yes, it can calculate the amount of the carbon dioxide emitted during the production of the electricity, if you know how much is emitted per kWh. Don’t really use that myself.

    It doesn’t measure what you waste, it measures what you use. But the amount of money you can save on your electricity bill is related to how much electricity you waste, and you can work that out by just keeping an eye on the display occasionally while you do the things you normally do. You can also experiment by switching off things you’d normally leave on to see how much of a difference that makes.

    For example, our microwave oven uses a ridiculous amount of electricity when left on standby, just to display the time. It gets switched off at the wall now, so that’s less electricity wasted.

  5. Meter Man avatar
    Meter Man

    WARNING!!!… dont go rushing out to get one of these devices because every home in Britain will soon have one… smart metering should have been introduced this year but has been put back till 2009. The unit in the property will also communicate with your gas meter and show everything you use including your carbon footprint.

  6. guppy avatar

    Not true, if you read (http://www.berr.gov.uk/whatwedo/energy/environment/smart-metering/index.html) this is says: “For domestic customers, the Government’s economic impact assessment casts some doubt about whether there is a cost-effective case for roll-out.”

  7. tim avatar

    On the other hand, e-on tried to persuade me to switch to them the other day by offering one free. They said it was worth £45, and by the look of the picture it tracks usage each day for comparison with previous days so a bit more advanced than the OWL.

    Of course, the catch was that I’d have to switch to an expensive fixed rate tariff…

  8. phil avatar

    I just purhased the OWl this week and although it does tell you what you use I am a little unsure as to the accuracy. When I set the meter up I read my house meter at the same time. The OWL says I’ve used 35kwh over the 4 day period – the meter says I’ve used 84kwh. Thats quite a discrepancy.

  9. tim avatar

    I haven’t seen any option on the OWL I have to measure total energy, only power (kW). How are you getting it to tell you total energy used? Maybe you have a newer one than I do.