Theo explained on 15/11/2020 :
Gas is tricky - it's hard to measure without interposing something in the
flow (or maybe Doppler ultrasound?). That means you're left trying to read
the exist meter optically - does it give a pulse or something a sensor could
be attached to? Apparently it's illegal to strap on sensors, but a
non-contact way to read it might be feasible - worst case a camera pointed
at the digits. It would likely need to be tailored to whatever meter you
have.

Short term energy usage figures can be scary, unless you are trying to
track down heavy usage appliances. Daily logs, or weekly logs of usage
are much more sensible. I log almost without fail, once per week and
feed the data into a spread sheet of E, G and W. My sheet takes into
account cost per Kw and standing charge etc. and shows a weekly charge,
total charges for the week and running totals for each year, plus
projected charges for the entire year. All I do is fill in the date and
the three numbers each week.