Radiant heating has naturally been used for centuries and is far more commonplace than you might think! Radiant heat is the warmth which is given off from a body. The sun radiates infrared which travels through space and only turns to heat upon touching a surface, we know the sand on the beach becomes very hot when the sun has been shining, this too is radiant heat, the heat given off from the sun and sand is radiant heat. This general warmth in the sand also heats the surrounding air. People naturally absorb and emit infrared, so when you receive a warming hug, you are actually receiving radiant heat.
So how does radiant heating work in my home? Infrared radiant heating panels become very hot, they need to run at about 80 degrees C to give off a very specific wavelength of infrared, the panel radiates infrared energy, like invisible sunlight, this shines across the room warming surfaces, the walls, floor and furniture, these warmed objects also radiate warmth to heat the air, making our room into a large mass radiating warmth feels lovely and cosy! We also receive this radiated infrared energy, it feels just like gentle sunshine soaking into our bodies – a perfectly natural way to make ourselves warm.
Radiant heating panels use electrical energy to make themselves hot and to heat other surfaces creating a warm thermal mass, this takes very little energy. The thermal mass gives off heat to warm the air, this is a more efficient way to heat air as now it is touching warmed objects and it will stay warm. As every surface has a similar temperature then there will be no convection of warmed air or circulation.
We commonly call the heaters in our home radiators, however they do not really radiate or give off much heat at all, they warm the surrounding air which is usually trapped inside the fin arrangement, this helps guide the hot air upwards and out into the room whilst also drawing cold air from the floor back inside to be heated. These are convection heaters, they rely on the principle that hot air rises to circulate the room. Convection of warm air means the actual starting point of the air temperature is very hot and gradually it cools as it moves around the room, so your thermostat should read an average but this obviously depends upon where it is positioned! Reheating the air over and over is now deemed a wasteful use of energy.