Newer cylinders, such as Worcester’s Greenstar range (www.worcester-bosch.co.uk), have thick built-in insulation, but older cylinders don’t. Fitting a British Standards cylinder jacket should cut heat loss by more than 75% and could save you around £25-£35 a year, according to the Energy Saving Trust. These jackets aren’t expensive - Screwfix has one for just £9.99 (product code: 43483, www.screwfix.com). If your cylinder already has a jacket, check that it’s adequate - it should be at least 75mm thick.
2. To fit a cylinder jacket, remove it from the packaging and allow it to fluff out. When it has expanded, tie one of the jacket’s straps around the cylinder (towards the top) and slide one of the insulation panels underneath (ensuring it’s the right way up) and up to the top of the cylinder. Do this with all the panels and once they’re roughly in place, thread the tops with the cord provided and tie in place around the hot-water pipe at the top. Ensure the panels are evenly positioned around the cylinder and then secure the other straps.
3. As well as a cylinder, some boilers have a cold-water tank, usually located in the loft. The loft floor should, of course, be insulated (around a quarter of the heat in an uninsulated house is lost through the roof, visit www.energysavingtrust.org.uk for more details), but not the floor under the tank because heat rising up from the rooms below will help prevent the tank from freezing. That said, the tank itself should be insulated.
4. The easiest option is to buy a tank jacket, available from DIY stores, which you should just be able to slot over the tank and secure in place. If your tank isn’t a standard size, there are DIY solutions. You can clad the tank in polystyrene sheets or rigid loft-insulation sheets, and tie them in place with string. Make sure the sheets extend down to the floor, especially if the tank is raised, and cut out holes for the pipes with a craft knife.
5. Don’t forget to insulate any water pipes in the loft (see my How-to Tip), as insulating the loft floor will make the loft itself colder because less heat will get through from the rooms below. One of the hazards of this time of year is burst pipes, so don’t take any risks. Insulate your home’s hot-water pipes everywhere you can access them, including under exposed floorboards, to reduce the risk of them freezing and to keep the water in them warmer.