Reducing Heat Loss from your Central Heating and Avoiding Cold Weather Damage

pipe_insulationAs mentioned in the loft insulation section, insulating your loft properly will reduce heat loss through the upstairs ceilings and as a result will increase the likelihood of your pipes freezing in cold weather and so they should also be insulated or ‘lagged’.

All pipe work that is not under the loft insulation must be lagged, as well as cold water storage tanks, expansion tanks and overflows. It is advisable not to install (and in fact to remove) loft insulation directly below the water tanks.

Another reason for lagging pipework is to reduce heat loss – if your boiler is a long way from any hot taps in your property then there will be a significant heat loss occuring every time hot water is required.


Pipes can be lagged with the following:

  • Mineral wool mat

This comes on a roll and should be applies as with a bandage, ensuring an overlap and no gaps. Stopcocks bodies should also be insulated.

  • Preformed split foam insulation

This comes in different lengths and with different internal specifications depending on the size (diameter) of pipe that you are lagging. It can be cut to size very easily and can be mitred for 90 degree bend and special shaped sections can be obtained for taps and these can be joined to the main body of the insulation by pushing the insulation up against them once in place and taping with strong tape such as gaffer tape, but not so tightly as to compress the insulation and reduce its effectiveness.

If you are lagging copper pipe in a modern house the pipes will most likely be 15m and 22mm with these sizes replacing the imperial ½” and ¾” sizes. It is also possible that plastic pipes have been used for some applications and these can be lagged as with copper.

Both of these types of insulation can be ordered online – you will find everything you need at Wickes with FREE delivery on many orders! Click here for more information

Hot water cylinders

Hot water cylinders should be insulated with a jacket to prevent them from cooling rapidly and a good quality jacket will save you money and increase the availability of hot water in your home. A well fitted 3” thick jacket will cut heat loss by up to 75% – the cost of these is around £10 and they will normally save you £10-£15 per year, making them absolutely essential.

Almost all cylinder jackets come in sections or segments that are assembled on the cylinder and held together with cords or belts are various points along the height of the cylinder. This system makes the jackets easy to fit around pipe work entering or leaving the cylinder as well as the outer body of the immersion heater and the thermostat and associated wiring which should not be covered. Care should be taken not to apply too much pressure to the jacket segments as this may compress the insulation and reduce its effectiveness. For best results, jackets should be fitted by following the manufacturer’s instructions.

New cylinders are supplied with a bonded foam jacket and do not require insulation – they are already more efficient than a standard cylinder with a jacket fitted, are more compact, and should be chosen as a replacement if your cylinder has reached the end of its life or as part of a new central heating and / or hot water system.

Cold water tanks

Cold water storage tanks must be completely insulated against the cold and the tank insulation should extend down to the insulation on the loft floor – additional loft insulation matting can be used to fill any gaps. If a return or vent returns water to the tank it is essential that this is allowed to continue and how you do this will depend on your own installation. Jackets should be fitted in strict accordance with the manufacturer’s instructions. Cold water storage tanks can also be insulated with polystyrene insulation board cut to size, noting that it should not be fitted directly to the top of a tank and that a secure wooden lid should be put in place first.

Where to buy central heating insulation materials

If you would like to undertake this work yourself and you are looking for suitable materials, you will find everything you need at Wickes with FREE delivery on many orders!