Without good insulation your hot water tank can lose a lot of heat and waste fuel and money. A 75mm (3”) insulation layer is a minimum requirement (most foams are less than 29mm, equivalent to a wrap-around jacket of less than 58mm).

We recommend that you fit hot water tank insulation to a thickness of at least 75mm (3”), such as by fitting a tank jacket.  This can be funded through the Green Deal or if you are in receipt of benefits through ECO or NEST.

Investment (Tank Jacket): Under £10
Financial saving: Up to £32 / year
Carbon dioxide saving: Up to £110kg / year

Fitting a tank jacket is an easy DIY job but be careful of hot pipes and do not cover the tank thermostat. Tank jackets are available from most DIY stores. All hot water pipes in the hot cylinder cupboard should also be lagged; this is also an easy DIY job. If possible you should also insulate the ‘primary’ hot water pipe between the boiler and hot water tank.

Investment (Pipe Lagging): Around £20
Financial saving: Up to £16 / year
Carbon dioxide saving: Up to 50kg / year

Hot water cylinders should also be fitted with a thermostat set to exactly 60 degreesC (no lower or higher). If you do not have a programmer or timer fitted we recommend that you do so, in order to prevent water being heated at times when it is not needed.  You will need to employ an electrician for this unless you are using a plug-in immersion heater in which case a timer adapter plug can be easily fitted. See

If your hot water is heated from a renewable source, you could consider replacing electric showers with showers powered by hot water from a nearby insulated hot water tank as this could save money.