The inside line on... zero-carbon daytime heating

CJ asks Andrew Brewster, technical services design engineer at CA Building Products, whether low-energy daytime heating is just hot air.

What is SolarWall?

SolarWall is a metal solar cladding system, which absorbs solar radiation, even on cold days. This creates a current of warmed air that circulates into the building and supplements or overrides a central heating system.

How much energy can it save?

Testing by the Building Services Research and Information Association (BSRIA) on a metal-clad factory in County Durham revealed that it reduced gas bills by 50%. SolarWall was installed on the south-facing wall of the industrial unit and tested for a full 12 months. The BSRIA report describes the cladding as producing "a significant amount of heat".

How does it work?

SolarWall is a perforated metal cladding that can be mounted as an extra skin to a building either as retrofit or new-build. It contains no liquids or wires, instead low-energy fans draw air heated by the sun through the perforations into a cavity to collect and be distributed around the building.

Are there any further developments?

We have also joined forces with AmbiRad to create an energy-saving heating system for commercial and industrial buildings. The idea is to team up AmbiRad's heating and ventilation equipment with our SolarWall. On a sunny day the transpired solar collector can deliver all of the buildings heating and at night or on cloudy days the AmbiRad system will supplement the temperature to the required degree.