The 2011/2012 graph shows the night outside minimum temperature in red and the daily amount of gas used in kWh in blue. The light red and light blue are for the 2010/2011 season. You can see how I've converted my meter readings to kWh here.
eTRV 'Sleep' button: Since February 2011, we have been using Chalmor eTRVs on all radiators. To make major savings in gas usage, we are putting many radiators to 'sleep' during the evening cycle (including bathroom, utility room, dining room etc. etc.) using the eTRV Sleep button while having them all on during the morning cycle. This has reduced my gas consumption by around 20%!
November 2011: Very mild compared to previous years so only had gas on once per day.
December 2011: Gas in now on twice a day, but using eTRVs have allowed me to put most radiators on low or many put to 'sleep' in unused rooms in the evenings - this really reduces gas consumption noticeably. The eTRVs are programmed for Economy in the evenings except in used rooms and I have been over-riding the programming by turning off unused radiators downstairs in the evening as a trial. My target is to see if I can limit gas usage to less that 100kWhr when on twice a day - without being in any way uncomfortable!
January 2012: We still having the heating on twice a day and using the eTRV sleep button to turn off unwanted radiators in the evening cycle. If we get cold during the day we light the fire. Wow! We have saved 32% of gas used so far compared to last year due to the use of eTRVs - this is projected to be 20% over the full year. This is even taking into account that we have had the heating on twice a day every day (due to 'return to nest' syndrome) whereas we often only had central heating on once a day on many days in previous years.
February 2012: Much colder so far than last year but this seems to have changed mid-month and warmed up by quite a bit.
March 2012: March so far has been warmer than last year so maybe we will be able to turn the heating off soon? I actually turned it off on the23rd as it has been so warm - June seems to have come early!
April 2012: Had to turn the heating back on in early April as you can see from the graph! Day time temperature went from upper 20s on late March to low teens in early April for a late winter cold snap! Wow! April is turning out to be colder that April for the first time since I've been measuring gas consumption. This has severely dented my gas savings as I've had to had to have gas on througfhout April for the firsty time. Oh well...
May 2012: Well, I thought summer was on it sway at last after such a cold April. However, I seem to have got it wrong with night time temperatures dropping down to the '5's and day time temperatures low teens.