Field trials carried out by Dunham-Bush in conjunction with a local authority have shown that fan convectors optimised for use with low grade heat from condensing boiler plant use up to 30% less energy than underfloor heating to maintain the same design conditions in classrooms.
The tests were carried out on two similar schools with similar boiler plant to provide a direct comparison.

'Better insulated school buildings lose less heat, which means that classrooms and other spaces are subject to greater temperature fluctuation due to internal heat gains and solar heat gains,' explained Dunham-Bush technical director Dave Shuttleworth. 'In order to achieve maximum energy savings, it's important that the heating system responds quickly to these changes.

'Clearly, underfloor heating is slow to respond to changes, whereas fan convectors offer a very fast response so that the heating is controlled in response to demand in the space. Furthermore, fan convectors have been designed to work with a wide range of water temperatures, making them ideal for use with low grade heat from condensing boilers and heat pumps,' he added.

Dunham-Bush Avant-garde fan convectors, for example, are configured to operate with lower flow and return temperatures (e.g. 55°C flow, 35°C return at peak loads). Their combination of low water content and low thermal mass ensures a rapid response to changing conditions, while the low return temperature also reduces standing heat losses from pipes.

Additional energy savings are achieved by reducing pumping energy by up to 87%, while an optional brushless DC motor reduces electrical power consumption by up to 50% compared to standard motors.