Trial shows fan convectors use less energy than underfloor heating
Field trials by Dunham-Bush and a local authority have shown that fan-convectors optimised for low-grade heat from condensing boilers use up to 30% less energy than underfloor heating to maintain the same design conditions in school classrooms. The comparisons were made of two similar schools with similar boiler plant,
Dave Shuttleworth, technical director, explains, ‘Better insulated school buildings lose less heat, which means that classrooms and other spaces are subject to greater temperature fluctuations due to internal heat gains and solar heat gains. 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 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.
For example, Dunham-Bush Avant-garde fan convectors, for example, can meet peak loads with flow/return temperatures of 55/35°C. Their combination of low water content and low thermal mass is said to ensure a rapid response to changing conditions, while the low return temperature reduces standing heat losses from pipes.
Additional energy savings are achieved by reducing pumping energy by up to 87%, and an optional brushless DC motor reduces power consumption by up to half compared to standard motors.