Well yes but value is driven somewhat by house size within the same area. When a council is deciding what new builds council tax is to be,for example, they take into account house size (I know this from experience) as well as other factors.
My post was more spit-balling as to how
@purplesky idea would be implemented given larger houses tend to consume more energy on average.... It wasn't a definite decision. Given what I said about house size vs council tax, it was a possible and valid way to determine it.
Anyways,
@purplesky has now come back and said same amount for every household so a moot point