Non tester. But a confused person who as tried to use British Gas....
It is a shame that a device that is such a good tool to show us the direct relation between leaving the lights on, tv, computers on standby rather than off, and how much it cost to tumble dry your clothes is so expensive.
£250 for the device, quoted to me by a local plumber who came to quote for my new boiler.
The British Gas person who came out to give me a quote, has managed to confuse me thoroughly by talking about loft insulation, cavity wall insulation, Green Deal, free smart meter, hydro flow requirements, all to the tune of 4k, but dont worry, British Gas will give you your cavity wall insulation for free, and your loft insulation, when you sign up with Green deal and pay it back at £73 per month over 10 years. Simples!
Not so simples. I was told I would get a call from British Gas about switching my dual fuel to them and get £150 cashback.
The person who called me could not give me a quote for switching based on knowing my current kw per hour deal with current supplier (perhaps he could not beat it?). Not possible to tell me if he could save me money based on my current rates, he would need to know how much I had actually paid. I am on a standing order deal, so he said Sorry cant help. 
I was told I would get a call back about Cavity wall insulation and loft insulation. The person who called me back told me I could possibly not get the Green Deal unless I am a benefits recipient. Would I anyway buy a Green Deal survey? £150 only! He could swipe my card there and then and send somebody out, no problem!
Erm, why would I do that when you have just told me I cant have the Green deal because I am not on benefits? So, he agreed that I should just have the free cavity wall survey for now.
So, the inspector came out. £450 for the work, done internally, so would have drilling holes everywhere. Unless I wanted to pay £800 for scaffolding. So, total £1250. He said "It is a shame you did not do this last year, when it was totally free for everybody, but there you go!"
Not quite sure where my free cavity wall insulation and loft insulation went. But it is sure as heck not Free from British Gas like the sales person who came to quote me my boiler said.
My quote then, as it stands, is 4 k, and includes Green Deal survey, Cavity wall insulation (which I have to pay extra for as I cant have Green Deal. Loft Insulation (which I wont be offered unless I pay for a Green Deal survey which there is no point having as I dont qualify) So what am I paying 4 k for? A Worcester Bosch boiler, at almost £1000, a Free smart meter, Hydro Flow, installations costs for 3k it would seem.
So, to look at these numbers. 1k deposit, and nothing more. 3k repaid by paying £73 per month for 10 years. This is 8760k! My new boiler will be paid off in 10 years, and will cost me a total of 9760.
Plus the cost of the cavity wall insulation. And loft insulation, should I decide to find a supplier to get a quote from on my own....
Having a quote from British Gas has resulted in 3 new people all telling me different things, I have so far dealt with 4 people, not a thing has been done, and all the work has become more and more expensive witch each person.
Will I use British Gas! Hell no!
I think I am going to use my local plumber.