I’ve been tracking my homes annual energy usage for several years now. For the last few it’s been fairly stable at around 19,000Kwh gas and 6,500Kwh electricity.
This year, with our new central heating boiler and maximised loft insulation, the figures are 15,500Kwh gas and 5,800Kwh electricity.
Taken together this reduces the carbon footprint of our home from 7.05 to 6.02 tonnes. The drop in gas usage is responsible for most of that, and is very welcome indeed. The electricity drop is good news too, though apart from forever going around turning lights off after my kids, I can’t account for any real changes in our usage, which is odd. However, I suspect it could be easily accounted for by something as small as using the oven a little less each week.
Now, if only I could find some reliable figures for the UK average to benchmark myself against…
Richard's Blog 
My British gas website account gives this. If you tell me the number of bedrooms, age, location, and whether detached I should be able to help. And number of inhabitants. Maybe.
I think I’ve found an answer here:
http://www.carbonindependent.org/sources_home_energy.htm
Average domestic use of gas across the UK is 18,000Kwh, with smaller and larger homes being arbitrarily classified as 12,000Kwh and 27,000Kwh respectively. It’s probably good enough to know that in a relatively large property I’m using less than the average gas consumption.
Always more to do though!