Energy monitors: Compare features & prices Onzo Smart Energy Kit review http://www.which.co.uk/energy/creating-an-energy-saving-home/reviews/energy-monitors/onzo-smart-energy-kit/review/

I have had my ONZO meter for over a year now and found it helpful as you soon learn what the expensive power users are. Some early battery problems were eventually ironed out. I too find that when I am not at home it uses energy that cannot be explained. I have recently had some solar panels fitted. The monitor cannot detect this so the reading you get are for total power usage. I also have a problem trying to identify high usage in 'history', although the different categories are useful. I have managed to reduce consumption. I wish there was one for gas.

I was interested in getting this energy monitor after your positive review, and being an SSE customer when I looked on their website it appeared I was on one of the eligible tariffs, so I called to ask them to send me a monitor. However, one thing they do not make clear anywhere is that they will only send you this monitor if you are on one of the specific tariffs that includes standing charge. SSE customer services are very good, and the advisor calculated that it would cost me several pounds more each month to switch to the standing charge tariff. As this monitor was meant to be "free" I said I'd rather not switch - in effect the money saved in one year by not switching means I could buy another monitor anyway. And when I asked why I couldn't have the monitor anyway, even if the costing calculations would not be totally accurate as I was not on a standing charge rate (I didn't really care about this aspect anyway), but simply to monitor my electricity usage in kilowatts, I was told they couldn't send the monitor "to customers who are not on the tariff as the monitor communicates with an online system which can only be set up once the account has changed to Iplan. " I thought people should be aware of these caveats to what might otherwise be a very useful device.