Rosie Millard: Thrifty Living

Want to pay less for leccy? elementary, my dear wattson

i can tell you what I'll be doing this Christmas drinking orange squash, eating salad and listening to one of the junior Millards playing a musical instrument. By candlelight.

The reason? The arrival in the Millard household of the Wattson, an extraordinary gizmo that measures the total amount of electricity your house is using at any one time. It converts the information into a display of watts used, and then, for non-physicists like moi, if you tip it backwards, it converts all that information into the amount of money it would cost if your house stayed like that all year. How exciting!

The Wattson is very stylish, looking somewhat like a funky object in the V&A or Elle Decoration. Indeed, it was designed by three former students of the Royal College of Art. You can get it to indicate electricity usage via a system of mood lights; blue for low, purple for medium, red for high. The lights move around a bit. Blue, with "gentle breathing behaviour" indicates that you have, say, a single light-bulb on. Purple ("a little more active"), and you're watching I'm a Celebrity. Red, "very active", and you are boiling up a Pot Noodle, or tumble-drying a duvet.

After spending an engaging 20 minutes or so putting in batteries and clipping the little transmitter on to a cable by our fuse box, I was ready to try out Wattson. The only lights on were the halogen ones in the kitchen (about 20, actually, but our kitchen designer assured me this was the minimum a truly modern kitchen would tolerate).

Blimey! If we left only those on all year, our electricity bill would be about 2,700. Mr Millard switches on the kettle. Immediately, the digits do a little flurry, coming up with not 3,000, not 4,000, but an astonishing 5,670. Just for a cup of Nescaf!

I then attempt to blow up the Wattson by seriously over-revving it. All right, I decide; I'm going to switch all the lights on, up and down the house, plus two bathroom fans, a CD player, two televisions and the oven. And the kettle. How much? Go on, go on 7,824, the Wattson calmly tells me.

I decide to go for gold. "Go," I order our nanny (only jokingly; I wouldn't dream of ordering our long-suffering nanny around, ever). "Go, dear nanny, and switch on the TUMBLE DRYER." She beetles off. After a minute, the Wattson goes into digital meltdown, coming up with the astonishing figure of 10,100. And only on the low-heat option, too!

I call DIY Kyoto, makers of the Wattson. "Did you hit 10,000?" says Greta Corke, one of the trio of Wattson inventors. She sounds a bit too pleased about it. "Well, those electric heaters, which you can buy for a tenner, have the same effect as a tumble dryer. They are a false economy. You think you're buying something cheap, until you get your electricity bill. I'm much more aware of my electricity usage, now." How much has she saved, though? "Oh, around 20 per cent of my bill." Our bill is usually about 1,800 a year, clearly thanks to the 20 halogen lights in the kitchen, so it will be interesting to see what a difference the Wattson makes.

The device has been on sale for two months now, at 149.50. There's a companion bit of software, Holmes (geddit?), for download from the DIY Kyoto website that will archive your home's energy use and let you chat to other Wattson addicts.

It's strangely exciting, I have to admit. No sooner had I recovered from tumble-dryer shock than I remembered the box of low-energy light bulbs, recently bought but somehow, err, not installed. But now I have the Wattson to please, so why wait?

So it was up with the stepladder and on with the low-energy bulbs. This had a deeply pleasing effect on the Wattson; its lights went almost (but not quite) blue, and its digits crept down to a most gratifying mark, somewhere in the one thousands. Interestingly, a stew Mr Millard was cooking seemed to make no difference once the oven had reached its temperature. While it was heating up, it was ruinous.

Our house is now of a crepuscular nature. We boil water on the stove. We wear damp clothes. Well, not quite, but it's amazing what a little bit of information and some funky mood lighting can do to your energy footprint. And, hopefully, to your electricity bill.

www.diykyoto.com