Reading the small print, I thought I'd found the answer, "We reserve the right to monitor your usage, including time of day usage." (I should explain that the thing comes with a link-up to online software). Decent time-of-day usage data are highly valuable to an electricity provider, so they can optimise their output.
I've been very interested to see how much power different things use. The fridge and the central heating pump are our main 'background' users of electricity, taking 100-200 Watts each, but not all the time. I was relieved to see that the laptops use very little - about 40 Watts, and again, not all the time. Right now the monitor is displaying zero, although I have the computer plugged into the mains.
The little light by the power cable shows the laptop is plugged in and switched on, but the electricity monitor says it's drawing no power
This big users are predictable, but still startling. We all know that electric kettles use a lot of power, but seeing the monitor shoot up to 2.5 kW is a striking reminder of that fact. I'm sure it's going to encourage me to heat less water (so it's on for less time) and to make the tea straight away, so I don't have to reboil.
The washing machine also uses kilowatts, but I'm not sure I'm ready to switch to hand washing just yet. The real biggie, though, is the shower. We have an electric shower which is pathetically feeble, yet still manages to use 7.5 kW, and we use it for much longer at a time than the kettle. We really must crack on with those solar panels!
As well as power consumption, the monitor has a built in thermometer and displays the temperature. At first, I thought this was an added bonus. Most lists of tips for saving energy include advice to turn the thermostat down a degree or two, so a thermometer fits with that approach. However, this one is slightly different.
The accompanying booklet informs us that a temperature "below 17°C is considered too cold for healthy living," and "If flashing it is below 13°C, please turn your heating up." This thing is geared up to tell us to increase our heating, but will never tell us to reduce it.
Ever since it came into our house, this thing has been complaining that it's too cold:
Not only does it complain, but it consistently reads two degrees lower than the old fashioned thermometer we have on the wall. Call me cynical, but this company sells gas, too...
*We do keep our house cool but I have to agree that, even allowing for the two-degree error, 13°C is on the chilly side. This is because our central heating has broken, but that's another story.