Installers are being reminded of the impact improvements to the fabric of a building can have on the efficiency of a heating system.

Martyn Bridges, Director of Technical Communication and Product Management at Worcester, Bosch Group, is calling for heating engineers to consider the age of the entire heating system, and the heat loss of the property, when replacing a standard efficiency boiler with a modern, condensing appliance.

Martyn explained: "Given that around 80% of houses in the UK were built before 1960, the majority of our properties have been designed during a time where energy efficiency was not at the forefront of homeowners' minds. Modern improvements such as adding double-glazed windows and fibreglass roof insulation significantly improve a property's heat loss, and this can have a knock-on effect for the most suitable water temperature inside the radiators.

"When a heating system is first installed, the radiators in the property will be sized on the original heat loss of the property. However, as homes are improved to be more efficient, fewer kilowatts of energy are required to heat the building and the radiators in place could then be considerably larger than actually required.

"With this in mind, the flow temperature of the boiler to, and return temperature from, the radiators can often be reduced accordingly – allowing the boiler to condense fully while still heating the living space to the desired comfort level."

Martyn continued: "It's important for installers to remember to check the age of the system when changing a boiler in the property and if possible, trace back the history of heating system. In the event this isn't possible as the house has changed hands since the original heating system was specified, it would be advisable to undertake a full heat loss calculation for the property. From this new calculation, installers can determine whether the radiators are now larger than needed and if they are, can take the necessary steps to replace or run them at a lower temperature to ensure homeowners are provided with a highly efficient heating system."

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