Insulating a hot water cylinder

Many people think that an uninsulated cylinder is providing a useful source of heat in an airingcupboard, but in fact it squanders a surprising amount of energy. Even a lagged cylinder should provide ample background heat in an enclosed cupboard but if not, an uninsulated pipe will.
Proprietary cylinder jackets are made from segments of 80 to 100mm (3 to 4in) thick mineral-fibre insulation material wrapped in plastic. Measure the approximate height and circumference of the cylinder to choose the right size. If necessary buy a larger jacket rather than one that is too small.

If you should ever have to replace the cylinder, consider buying a pre-insulated version, of which there are various types on the market.
Thread the tapered ends of the jacket segments onto a length of string and tie it round the pipe at the top of the cylinder. Distribute the segments evenly around the cylinder and wrap the straps or string provided around it to hold the insulation in place.
Spread out the segments to make sure the edges are butted together and tuck the insulation around the pipes and the cylinder thermostat.