How does Infrared Heating work?
This is how Infrared heating works.
The main points
Feeling warm or cold does not actually depend on the temperature of the surrounding air. For example, skiers and mountain climbers do not freeze even in extremely cold, but sunny, air. They are bathed by rays from the sun, which include infrared. We experience this heat directly on our skin and by rays reflected by the environment (snow, stones, earth etc.). When infrared waves touch a surface, heat energy is released regardless of the surrounding air temperature. So people on a winter sports holiday are able to sunbathe despite the low temperatures - all thanks to Infrared.
An experiment at the John B. Pierce Laboratory, USA, clarified the different human perceptions of heat:
"Test persons in a room with a temperature of 50°C (122°F) of warm air and cooled walls froze deplorably; when in a room with a cool air temperature of 10°C (50°F) and warm walls, they broke into an unpleasant sweat."
Feeling warm has nothing to do with air temperature. It is all about absorption of infrared from our surroundings (warming up) or stopping ourselves losing radiation (cooling down) to a "colder" outside.
If we think of this in terms of heating devices, then it implies that instead of having to heat volumes of air any more (i.e. Cubic Metres of air in a room), you only have to heat surface area (i.e. Metres Square). Give or take, this implies about 32% less "installed capacity" requirement from your Infrared heaters when compared with Convection-type heating. This is the fundamental reason Infrared heating is so energy-efficient. (More detail on energy-efficiency here).
So systems that "heat the air" (blow heaters, convection radiators) are less effective heating systems than those that "heat the surroundings" through radiation (infrared heaters, stoves & fireplaces) because:
What are Infrared Rays & How do they heat you?
Infrared lies just under the visible light range beyond the "Red" end of the visible light spectrum. These wavelengths are longer ("infra") than waves in the visible light spectrum. The longest of these wavelengths is Red. Hence the name "infra red". Even longer-wavelengths in the Infrared Spectrum are called "Far Infrared", which therefore also explains why you will hear this term.
How do Infrared waves heat you?
Infrared waves do not need a medium such as air or water to travel through. They travel as easily through air as through the depths of space, producing heat only when they strike an object such as the surface of the earth or a wall of a house. When radiation from Infrared panels hit an object (walls, ceilings, floors, interior objects), the rays cause molecules they strike to oscillate. The energy continues to be absorbed by the molecules in that object until they oscillate at the frequency of the radiation, at which point the radiation is then reflected. In other words, all objects in a room become radiators. IR continues to radiate through a room until all its energy is absorbed and all objects warm up and begin reflecting heat back. Humans feel this oscillation as warmth. Peoples' first reactions in being in a room warmed by Infrared are always one of surprise. They feel so warm, but they cannot immediately detect the source of the heat.
How do the panels work - what makes them "Far Infrared"?
The energy-efficiency of Far Infrared panels critically relates to their surface temperature of 85-100°C.
The “elements” of Far Infrared heaters are typically ceramic plates containing very highly stretched and densely-wound carbon or nickel cores. The high density of the wound “core” allows a very much lower input wattage to produce the desired output temperature evenly over the whole surface of the heater. There is no “magic” material here producing infrared for “no resistance”. It is very densely wound, very thin core material that being so thin and densely coiled, it draws much lower input wattage to reach only a “low” temperature (100°C being “low”). The ceramic is also an ideal host, as it is electrically non-conductive, has excellent heat transfer properties and implies no other impedance (electrical, thermal or “state” - which stays the same over a large temperature range).
The key to the energy-efficiency of Far Infrared is the low, constant surface temperature, which influences the low power input and defines the wavelength of emitted radiation as “far” infrared - being 7 - 15 microns. This is critically important when weighing the slightly more expensive purchase price of properly certified, tested panels that output 100°C against the much cheaper (to purchase) panels of various origins claiming to be "Far Infrared" but which operate at temperatures either well below or well above 100°C: they cannot by definition be outputting the correct wavelength heat to qualify as far infrared, nor can they therefore be making the energy-savings claimed by their salesmen.
For example: a Panel made for European Voltage (240V) imported into the UK with no optimisation for UK voltage (230V) actually runs too cool (and some even still come with their European plug baked on. Now there's a clue!). A panel that runs too cool will convect, rather than radiate and you will need to have it on longer therefore using up more energy.
A panel made for 220 Volts will run far too hot, making it neither safe to use domestically, nor energy-efficient. Again there are suppliers in the UK who do this. Check the panel temperature! It must be between 85 - 100°C!
If you are in any doubt what you are being offered, please come to us for clarification.
Is Infrared harmful?
"Infrared Radiation" has nothing to do with "Ultraviolet Radiation" which is beyond ("ultra") the shortest wavelength in the visible spectrum ("Violet" - hence "Ultraviolet"). Infrared is classified as a "Non Ionising" radiation (lacks the ability to physically alter the molecules it strikes) whereas Ultraviolet is an Ionising Radiation. Unfortunately however, because the word "Radiation" applies both to Ultraviolet and Infrared waves (and other more extreme wavelengths) people may be hesitant to accept the safety of Infrared devices because of the word "Radiation". The governing body for non-Ionising radiation (The ICNIRP) states of the health implications of Far Infrared (IR-C):
"The contribution made by the IR-C spectral region (3–1,000 miu m) is normally of no practical concern from a health hazard standpoint."
If it helps, remember that Far Infrared heaters are used in modern saunas and in Baby incubators and the wavelength they emit is 7-15 microns - which is equivalent to the "vital range" of heat radiated from the human body itself. Just remember police helicopters have cameras to detect the "Infrared Radiation" humans naturally emit. We perceive warmth when we're absorbing Infrared and we feel cold when we're radiating it out to our environment. We are Infrared heaters ourselves!!!! Infrared is a perfectly natural, safe form of radiation that actually possesses certain health benefits which we look at in more detail elsewhere on this site.
Is Infrared Heating new?
No it is not. Heating by infrared radiation is as old as the use of fire by man. The Roman hypocaust heating system was the first central heating system! It functioned solely by infrared. The Romans constructed a chamber to enable the passage of steam under the floor tiles. The floors warmed up and radiated heat into the room, whilst leaving the actual air temperature of the room unaltered and fresh.
The tiled stove is another legendary example of radiated heat. A correctly placed tiled stove warms up the inside surface of a house's external walls, increases their surface temperature, leaving the temperature of the air in the room cool.
Radiant heating is by far the most natural and comforting form of heating for man - because it mimics the heat of the sun - and because when the fires went out, things remained warm! If your central heating goes off, things cool down rapidly because only the air has been heated!
The paradox of the last 50 years is that a less efficient way of heating - convection - created by central heating systems - has come to dominate becuase it became cheaper than any radiative form of heating.
What is now new about Far Infrared, is that a technology has now emerged, that allows us to produce Radiative heat again - cheaper than the convection-based (oil, gas, heat pump) alternatives.
New Incentives for Infrared
"Radiant Far Infrared" products have now been approved by the Department for Energy and Climate Change (DECC) in the "Green Deal" - an initiative designed to encourage people to invest in effective Eco Technologies and payback any costs of finance from the savings they make from their bills. Green Energy (eu) was instrumental in helping achieve this official recognition and it means you can be sure our products are those approved for use in this initiative (because they do what they say they do). We can discuss our performance figures with Decc and the BRE: our competitors can't.
Get free training excerpts here!
Green Energy (eu) and its trade partners all insist their installers take accreditation training in Far Infrared Heating. WE ARE THE ONLY ONES IN THE UK TO DO SO! Here are some excerpts taken from the standard training course for Far Infrared Heating.
Author: Greenenergy (eu).