[derekgas]

There is another thread about this somewhere, I think entwisi started it, the cost of your gas bill will be massively variable from one house to another, number of people, amount of cooking, hot water useage, heating usage, glazing, insulation, etc, I know that emmamums system was not very economical, the boiler itself is about 70% efficient at best, if you have a condensing boiler, it could be well over 90% efficient. I could go on and on, again, but i wont lol.