If you have a water cylinder it should be properly insulated, if not you could be losing £40 a year. A cylinder jacket only costs about £15 from all good DIY shops and fitting is an easy job, so there is no excuse.
All the jacket comprises of is thick insulation that you wrap around the cylinder, like a jacket. Most modern cylinders will have the insulation all ready fitted to it, so a jacket isn’t required, but if you have an older cylinder, or you can feel the heat coming off the cylinder you should consider getting one fitted.
The payback will occur in 6 months! So this measure will fit nicely into the Green Deals Golden Rule.