"Roger Mills" wrote in message
...
In an earlier contribution to this discussion,
Geronimo W. Christ Esq wrote:

Andy Wade wrote:

4. Multiply by the declared calorific value (CV - see last gas
bill) to get consumption in Megajoules.

I've always wondered why this is required. Does the calorific value
vary ?

Yes, a bit. Looking at mine for the last 3 years, it has ranged from 39.0
to 39.6 - not a massive amount, but about 1.5%

Same here. Ranges from 30.9 to 40.7 over the last 5 years

Adam