Just thinking on this very subject today.
Ask people what their Electricity/ Gas or Water usage is - although they may not know off the cuff - the information is available (on their bill) and if you want to read the meter regularly - you can soon learn your daily consumption and variations through season and differnt people staying in your house (Elderly relatives...!).
I have gone on too often here about how much difference "awareness" - down to the your daily consumption rates - makes to our consumption of utilities. We did a 1010 campaign effort and easily acheived 10% reductions in utilities usage - simply through being aware - and water was nearer 40% down - and electricity nearly 49% down compared with previous year
Many of us in the Highlands use Oil and /or wood for a portion - or all of our home heating. This is where it gets more difficult.
Wood - I know how much we get delivered as I stack it, chop it and saw it - although weight is a guess.
Oil (to get back on the thread) - I know how much we get delivered (approx 30% less than 2009) - but as we get a delivery 1.5 times a year typically - it is quite difficult to assess where and when the usage occurs. I reckon my Bamboo dipping cane is more use than The Watchman device many of us have.
An inline meter like that shown seems the ideal solution - even better a repeater that displays usage somewhere visible (next to Elec and outside/inside temps) ......but £200 unfortunately will take quite a lot of savings to cover.
Though if these could be subsidised greatly to encourage usage reductions........
