Well, after handing over a very large cheque to the oil man, I've been giving saving energy (so money) a great deal of thought. Problem we have is our oil boiler is a combi, which wouldn't have ever been my choice. We can supplement space heating with wood, which hasn't changed in price (yet), but hot water is now costing a fortune, both because of the fuel and also the poor insulation. I've checked the insulation, discovered a rat has been removing it to get to the warm tank and have repaired it . We're off to town on Monday to buy an axillary hot water tank. 100 litres with a standing load (heat loss) of just 1.07Kw per day. It's a mains pressure unit, as they all are here, which will simply be fitted into the hot water circuit pipe on the wall. Then the boiler will go off, or be turned down to its minimum of 30C and the new tank switched on. Electricity prices have been capped to a 4% increase here, so by my calculations this installation will pay back in 18 months.
If you have a hot water tank, give some consideration to the insulation, because it could be costing you a lot.