Our house is quite a large old 1932 four bedroom detached house and the central heating boiler is a 20-year old Potterton Netaheat ( Boiler efficiency database ) and is not as efficient as a modern condensing boiler.
The central wall-mounted boiler controller is of a similar vintage, but does exactly the same as any modern controller. The radiators and water heating are controlled separately - which is a must. Depending on the season, we have the gas heating on twice a day for 2.5 hours in the morning and evening.
To understand the gas usage data presented on this site, you need to understand how we use the heating on a daily ands seasonal basis.
Summer: The gas room heating is turned off completely using the boiler controller. We only use gas for cooking and heating water (controlled by the boiler central controller) from around may to October. We try and turn heating back on to twice-a-day heating as late as possible in the autumn and off as early as possible in the spring.
Spring and autumn: These are the seasons when most gas can be saved by turning radiators on only once per day in the morning for as long as possible. On the occasional day when its a bit chilly we light a log / coal fire to avoid turning the central heating on. We have done this for as many years as I can remember.
Winter: We have the gas central heating on twice a day. We have it on for 2.5 hours in the morning throughout the house (except unused bedrooms where radiators are turned off permanently). In the evenings of 2011/12, we have used eTRVs to put most radiators to 'sleep' automatically (i.e. turned off) in the evenings. This has considerably reduced our gas consumption through the winter months.