Ecotip – The 60 degree reminder

WHATEVER ENERGY-SAVING tips the government may put out this winter, here is an explanation of last winter’s message to ‘turn your gas boiler settings down to 60 degrees to save energy and £££’.

Most gas boilers are condensing models – either combi boilers which heat incoming water directly from the mains or store heated water in a cylinder. The system is controlled by a room thermostat that tells the boiler when to switch on and off to regulate room temperature, and boiler controls to set the temperature of the water to radiators and hot taps/tank. The latter are the ones involved in the 60 degree message.

While creating very hot water, then having to add cold water to make it usable is daft, the main reason for reducing boiler temperature is to allow the condensing boiler to work at maximum efficiency, as it recovers heat from the combustion exhaust gases rather than discharging it. You can get gadgets to control the system’s efficiency automatically, but a simpler approach is to keep the temperature of water flowing to the radiators as low as practical to heat the house, and the temperature of hot water at a reasonable level, with 60^oC as the starting point. If you can cope with a lower temperature, then so much the better!

The same simple advice does not apply to hot water tank systems. Bacteria can develop in a warm water tank, so it is important that this temperature climbs above 60^oC on a regular basis to kill them. This suggests that 65^oC is the right temperature for the boiler controls (the temperature of water in the tank will be lower than the boiler temperature). If you have separate controls for hot water and radiators, then the radiators can go down to 60^oC, as above. If you had the time, patience and easy access, you could change the boiler temperature at different times of the day or certain days of the week, as heating the water to 65^oC twice a week is enough to prevent bacteria growth.

Finally, turning down the room thermostats will save money, but may not be comfortable. Yes, you can wear thermal underwear and ski jacket indoors, but draughts may be the issue. Please do a draughtproofing survey of your house and check whether there are simple changes to be made (see www.draughtbusters.net for advice on how to do this).