Hot Water Cylinder Insulation - When is it needed?

Your hot water cylinders require decent insulation so that the water remains hot and you do not spend money heating it again.

At a certain time of day, hot water cylinders are heated up and only used if you operate a hot tap. You must have a high degree of insularization so that the water remains hot anytime you choose to use the tank and you don't have to turn it on to reheat the water.

Many cylinders include or will have a special insulation cover known as a tank jacket, wrapped in dense insulation foam. You need to make sure the insulation is strong enough - 80 mm (three inches) is advised. You also need to make sure it suits tightly and is well sealed if you have a tank jacket, with no holes that will let the heat flee.

When should I add extra insulation?

If you have a hot water cylinder and its insulation is less than 80 mm (3 inches),  you can consider adding some more.

If a hot water cylinder is used in your hot water system, then you need to ensure it is properly insulated. The cylinder itself could have been made without insulation, or before it left the manufacturer, it may have been covered in spray foam instead of an insulating jacket.

There is just about 25 mm (one inch) of insulation in certain insulated cylinders. If you have a pre-insulated cylinder, at any level when there is a void to fit a thermostat or immersion heater, you can typically see how thick the insulation is.

  •  If the insulation is too thin, a tank jacket (or a separate jacket) can be fitted to get you to the 80 mm required.
  •  You can insulate as a priority if you have a cylinder with no insulation because you're spending a lot of money heating up water that cools off before using it.
  •  If you have a hybrid boiler that heats water on-demand, so you don't need cylinder insulation.

For professional insulation, please get in touch with one of our team members here.