AlertMe Energy monitoring kit is giving me OCD

Ten days ago, I installed AlertMe's Energy kit. It comprises of three items: a sensor that clamps over your electricity meter's power wire, a box of batteries that powers the sensor and sends the signal to a receiver, which is the third component, and which plugs into your broadband router. The signal is sent to AlertMe, whereupon you can view the data at AlertMe's website.

On your first visit to the site, you have to enter the code which is on the receiver unit in order for the system to know which data stream is yours. Then, after a few more configuration screens (oddly, not one to enter how much your supplier charges per kWh - you have to find this hidden-away setting on the website later), you get to the juicy part - your home's power consumption.

I didn't expect the sensor to be particularly accurate, or for the feed to be updated in real-time, but was wrong on both counts. The website's interface is clear and easy to understand. There are four icons, one which shows your current power consumption, a second displaying how much the electricity has cost you so far today, a link to graphs of previous usage and, lastly, a System link for monitoring and configuring your kit.

The most interesting, naturally, is the cost of the power used, as this gives you a hard figure for what you're paying. This is enlightening and, although I dislike the word, empowering, too. Until now, I'd had to wait for the bill to drop onto the mat every quarter to find out how much power I'd used, and therefore how many hundreds of pounds I owed for it. With the Energy kit, I could see from minute to minute how much the electricity was costing.

It may sound obvious, but although you might have an idea of which appliances use the most electricity, it's quite amazing to see concrete information on your screen which shows you not just how many watts are being used, but exactly how much this is costing. Until this information is real in your head, it's very easy to ignore it, and baulk at the bill when it arrived. The ability to view power consumption in real-time - and the cost - means you can start going about the process of cutting down your usage, and saving money in the process. (I could have lied and said I was only bothered about saving the environment, but let's face it, this is a nice bonus that comes from the motivation of having a little extra cash in your account at the end of the month.)

After the initial excitement of all this has subsided, I did a couple of tests just to see exactly what things cost. I discovered that, for example, boiling a kettle of water costs around 3p, while drying a load of washing in the tumble dryer increased the day's running total by around 30p. Testing the accuracy was easy, too, as you can the precise wattage being used by clicking on the main power meter icon. Noting the figure, which is shown to the nearest watt, I flicked on a 60W light and was amazed to see the power instantly increase by roughly that amount. Impressive stuff.

Better still, it's possible to view a graph of power use over time, so you can compare one day with another. For example, I could see two spikes of around 2kW between 12am and 6am one night, but nothing the next. Given that I'd set the dishwasher to come on during the night, I could deduce that was the source of the power consumption, particularly as I knew that it paused for around half an hour during its economy cycle.

AlertMe's graphs aren't particularly easy to see, as the line graphs are too detailed. Fortunately, AlertMe has partnered with Google to send the data to its new PowerMeter gadget. This means you can see a usage graph directly on your iGoogle homepage. PowerMeter shows area graphs, which are far easier on the eye. You can view the data by Day, Week or Month, with the latter two showing bar graphs to make it easier to compare overall power usage.

You can enter the cost of your electricity and currency, as well as view your current usage compared to a budgeted amount, so you can see, for example, if your usage is above or below last week's. I'm convinced that PowerMeter's 'Compared to others' graph is broken, though. For the last ten days, it's been showing my average usage as the same as a 1-bed apartment. Given I live in a 4-bed house, this can't be right, as I'm not that frugal.

However, this I'm a little worried that AlertMe's kit is giving me (and my wife, for that matter) OCD tendencies. Ever since I installed the kit, we've had the laptop signed in to AlertMe's website, constantly keeping a check on the power meter and current cost. We've even been turning lights off in every room except the ones we're in to see how much money it saves, and boiling only the amount of water we need, rather than a full kettle every time. That may be slightly laughable, or maybe we should view this frugality as obvious money-saving tactics we should have been employing all along.

Thus far, I'm uncertain whether this £70 kit is good value. On the one hand, it gives you information that's otherwise a mystery, such as the frightening amount of 'permanent' power being used by all those devices that remain on constantly like clock radios, PVRs, house alarms, fridges, freezers etc. On the other, though, is it going to enable to me to save any more money than I could by simply turning things off when I don't need them? That's a question I hope to answer in a month or two, when I discover whether we can use less power in December without resorting to ridiculous measures like trying to dry washing on radiators, or living in the dark.