This is a great looking unit. It has a fool proof instruction manual - however they didn't count on someone as foolish as me!

As you can see from the unboxing - this device is pretty svelte. Once on its stand and plugged in, it will nestle unobtrusively on a bookshelf.

Smaller than a paperback book

Set up is fairly straightforward.  Plug in, set the date and time, set your tariff costs, pair the device with the sensor.  That's where I came unstuck.  I was left facing the "WAITING" screen for ages.

Pairing

I tried everything. I even went to the back of the manual to find out how to reset the damn thing. I know a true geek never reads the manual but it was late and I was desperate... Then, inspiration stuck.

Take a look at the back of the unit.  There are two small black buttons.

Left button. Right Button

One of the buttons is for pairing the electricity sensor, the other is for pairing the gas sensor.  Like a fool, I'd been trying to pair the electricity sensor with the gas unit.

As anyone interested in usability knows, such things are never the fault of the user... ahem...

I was being daft, but a small label next to each button wouldn't go amiss on the next version of this device!

Once paired, I clipped the sensor around the live wire coming in to my meter. Then I plugged the sensor into the transmitter.

Near the meter

The transmitter is fairly small, so it's easy to rest it somewhere in your utility cupboard.  The sensor wire is quite long, should you not have a shelf near.  The transmitter has a range of about 30 metres according to the manual.

Both the gas and electricity sensors have multiple inputs - should you have a complicated setup such as three-phase electricity or an unusual boiler.  The Duet comes with one set of sensors for each - you can buy more if you need.

Lots of sockets

The majority of the size of the units is taken up by battery housing.  The batteries should last a year - there's a display on the Duet to tell you when they're getting low.  You can buy AC adaptors for the units if you have power sockets nearby.

Pairing the individual plug-bugs was simplicity itself.  So I've ended up with this rather fine little display.

Success!

Having done the electricity, I left the gas sensor for another day.

It's already an addictive little display.  Switching on the halogen lights in the kitchen doubles the number of kW of electricity the house uses.  Something as switching off a TV from standby is enough to make a noticeable drop.

The Duet is smarter than most other monitors I've seen.  Rather than just showing you how many kWh you've used or how much your electricity is costing, you can set a "limit" for the day.  It suggests about 10kWh per day for a small family - the speed dial then tells you whether you're over or under your daily "allowance".

Our current energy supplier allows me to crudely track my usage based on my meter readings - here it is.

Electricty Usage

I don't know whether 12kWh a day is particularly excessive.  I mean, all I've got running are a fridge/freezer, a FreeView box, a TiVo, my home server, my security camera, my DAB alarm clock, my ADSL, my WiFi router, my cordless DECT phone, my phone chargers, my...

I'm going to unplug stuff now. I may be some time...