Cylinder Thermostat can save energy and money
Have my neighbours done this?
What is it?
A device that helps stop the water stored in a cylinder from getting too hot
What will it save me?
Could save over £60 per year depending on your hot water use
How do I get it?
It needs to be installed with other controls by a specialist contractor
What does it cost?
Costs around £120 fitted (2013)
What are the technical details?
A cylinder thermostat is needed to maintain the temperature of water in a cylinder connected to a central heating boiler. Not having one will cause the boiler to keep switching on and off, which is very inefficient, and could allow the water to become too hot to be a scalding hazard nor too cold to allow harmful bacteria to thrive.
The thermostat should be set at 60oC and fitted towards the bottom half of the cylinder so that the central heating boiler will heat the majority of the water in the cylinder. As the water is heated it will rise to the top of the cylinder by convection, so it's normal for the water from the top of the cylinder to be hotter than the thermostat setting.
There are several types of cylinder thermostat with the older ones being mechanical with a bimetal strip sensing the temperature and operating a switch. More modern ones will be electronically operated and the thermostat may be in two parts with a solid state sensor attached to the side of the cylinder and connected to an electronic control box.
However, a cylinder thermostat is only part of the equipment needed and this would need to be fitted by a heating contractor. To work correctly, the thermostat needs to operate a motorised valve fitted in the cylinder heating pipe and be connected to the programmer.