Hot Water Cylinder Insulation can save energy and money
Have my neighbours done this?
What is it?
It keeps the heat inside your hot water cylinder
What will it save me?
Potentially saves over £150 per year
How do I get it?
DIY job to fit an insulating jacket over your existing uninsulated cylinder
What does it cost?
Costs around £30 to do it yourself (2013) or up to £150 fitted by a contractor
What are the technical details?
Hot water cylinders have a large surface area; they are often heated to a high temperature and have a significant heat loss. This will cause the water to cool down quickly and require the boiler or immersion heater to switch on again to re-heat the contents. Insulating the cylinder will save a lot of energy and money. If your hot water cylinder has no insulation at all you could be wasting over £150 a year.
The recommendation is to use a 160mm thick sectional jacket tied around the cylinder or a factory applied foam covering at least 80mm thick. Older cylinders may have no insulation (bare copper) but normally have a sectional insulation jacket tied around (80mm thick red jacket). Older foam insulated cylinders are likely to be less than 50mm thick.
In either case, the easiest solution is to add another 80mm thick jacket over the existing insulation, remembering to cover the cylinder thermostat. In addition, the pipes should also be fitted with preformed pipe insulation. Sufficient heat will still escape to keep the cylinder cupboard warm enough to “air” clothes, but not enough to warp the cupboard door.
Fitting another jacket to the cylinder is a fairly simple DIY job and should cost little more than £15 or £30 if you need to fit 2 jackets. Fitting pipe insulation is also quite easy and adhesive tape can be used to hold the insulation in position around bends.