It is very interesting to compare gas usage and minimum temperature this season to previous years on a daily cumulative basis. This will show how each year's seasons differ from each other. This should give some guidance to gas usage in the current season compared to previous ones.
Cumulative minimum night time temperature.
This graph show the average cumulative daily temperature of the current season compared to previous ones. i.e. in January 2012, it has been warmer by an average of 2 degrees each day than the previous two years. Therefore, theory says that gas usage should have been be less this winter.
The graph moves upwards when it's warmer this season and downwards when it's colder.
Gas saved in 2011/12 compared to 2010/11 to date:17.8%
Cumulative gas consumption in kWh.
In 2008/09 season, I was not really concentrating on reducing gas usage but was just monitoring what I used. We have saved around 4000kW hours compared to last year and even more when compared to previous years. Undoubtedly, this has been down to the use of eTRVs during the winter of 2011/12 as we are saving gas even when it has been colder as can be seen by comparing the graphs. You can easily observe that I started using eTRVs in early February 2011.
When the graph downwards I'm saving; when it upwards I'm not!
Cumulative gas consumption in %.
This is the same data as plotted in the above graph but calculated as a percentage.