Boiler computer could save 30%

The dramatic rise in fuel prices has had unexpected positive effects in highlighting the need for us to be more efficient in our use of energy.

At the very least householders will be turning down their central heating thermostats.

Simply reducing the temperature by one degree will have a positive effect and savings of more than 5% are possible. There are also products available that can increase your heating system’s efficiency without resorting to throwing away your current boiler.

Boilers often fire up unnecessarily when there is still sufficient heat within the system. When this happens the boiler is re-heating water that is sufficiently hot and the excess heat is wasted up the boiler flue - this is called dry cycling. It is like flooring the accelerator on your car when it cannot use any more fuel - the excess fuel goes out of the exhaust without being fully used.

Thermostats on French ballons  (boilers) are normally set to a skin-burning 85°C when a maximum temperature of  65°C is more than adequate - the extra is just wasted energy.

Typically, boilers are designed to work most efficiently with an 11°C difference between the flow (hot water out) and return water temperatures eg. out at 66°c and back at 55°c. The boiler setting is fixed and usually set to cater for the coldest external temperatures.
As most boilers have nothing more than a thermostat and timer to control them the optimum level of efficiency can never be achieved.

By fitting a “boiler computer” system efficiency can be greatly improved.
These continuously monitor flow and return values and internal and external temperatures, and based on this information control the boiler and increase efficiency.
Essentially this boiler computer controls the system based upon actual demand and not just what the thermostat says.

For the technically-minded the method used is called ‘variable thermal response’ and the controller constantly varies the threshold settings and firing cycle.

Genuine savings can be achieved - typically around 17% but as much as 30% is possible.
Installation is relatively straightforward entailing the fitting of highly accurate electronic sensors to the flow and return pipes of the central heating system (strapped to the pipes) and to an external atmospheric sensor.

Connections are external to the boiler and most already have convenient spare connections in their junction boxes for external controls.

Perhaps as a repercussion of spiralling fuel costs some boiler manufacturers are now building in this level of control as standard. If you are looking for a new boiler, check to see if such a control system is part of the package.

Although you will pay more this is a one-off while your heating bills are for life.
As a guide expect to pay between €650 - €1,200 dependent on boiler size.
 
This column is written by Marc Asker from EcoPower