Published on: Aug 13 2014
As aluminium is the most abundant metal in Earth, it’s a wonder that it’s not used for everything, but surprisingly, steel is still the most common material for radiators – in the UK.
The reason for this is that steel has typically been a much cheaper material to produce than aluminium, which whilst more abundant, requires more energy and effort to extract from the bauxite it’s deposited in.
It wasn’t always steel – in the mid 1800’s cast iron radiators (patented in 1861 by Messer’s Briggs & Nason) were the d’rigeur in Victorian Britain and the original design has been much copied ever since. The cast iron ‘school radiators’ are still fashionable in renovated period properties.
However, Cast iron does have some drawbacks, and not only weight related. It’s a very slow transmitter of heat, and takes an age to warm through and eventually radiate heat into the room. It is also quite brittle and prone to casting flaws, making it vulnerable to cracking and failures that are hard to repair. Aluminium on the other hand is a very lightweight material that can be reshaped and manipulated without compromising its considerable strength.
Pressed steel radiators, mass manufactured since the late 50’s have driven down the cost of central heating such that 80~90% of homes now have them. They have revolutionised the domestic central heating markets, and there are hundreds if not thousands of manufacturers and suppliers.
On the continent however, Aluminium (aluminium) radiators are far more widely used despite the cost disadvantage compared to steel.
This is mainly because aluminium radiators require far less energy to heat up. Aluminium is an excellent thermal conductor having an emissivity of 236w/m2K – nearly 5 x that of steel. This facet lends itself perfectly to radiators, meaning you don’t have to run them for a long time before it has an effect on the temperature of a room.
This responsiveness avoids the wasted energy of heating an unoccupied room and, in turn, results in lower water, gas and electricity bills. Indeed, looking on any radiator retailer’s website will show you that the BTU or Watt heat output of an aluminium radiator is considerably higher than an iron and steel radiator of similar dimensions.
Because aluminium radiators are so quick at getting to the desired temperature, it makes them very suitable for areas of a house that are only used occasionally such as an attic or a conservatory. Therefore, an aluminium radiator is much easier to manufacture, transport and install, making it a cheaper option than steel and cast iron from start to finish.
Aluminium is considered to be more environmentally friendly than steel or cast iron due to the relative ease in which it can be formed into complex shapes and is easily recovered and recycled. The lower melting point of aluminium means less energy is used during it’s initial processing, and because it is non-ferritic, is easily recovered from unsorted scrap materials. Whilst aluminium is the most abundant metal on earth, it still makes sound environmental sense to re-use to use aluminium that has already been extracted from the earth, rather than continually extract new raw materials which ultimately requires disruption and disturbance of the natural world.
ThermaSkirt is manufactured from typically 60% recycled materials, and takes best advantage of aluminium’s unique properties. ThermaSkirt has lower water content than a steel radiator of similar output (typically 1/2 to 1/3rd) which combined with its far higher emissivity, results in a very rapid response to heat demand.
Response times and even comfortable heat all around the room at low level, means that typically ThermaSkirt is at least 13% more effective and energy efficient than steel, and up to 25% more efficient than cast iron radiators.
By skirting the room at low level, it is possible to run ThermaSkirt at a lower flow temperature than conventional steel radiators, which can generate further cost savings and efficiency at the heat source such as the boiler. It is even possible to run a ThermaSkirt system on renewables such as Ground and Air source heat pumps.
