|What is radiant heat?
How does radiant heat work?
What are the advantages and differences against other forms of heating?
How does radiant heat affect our us and our health?
IS RADIANT HEAT?
Radiant heat is widely regarded as the most comfortable, healthiest and most natural
heating form available.
It is based in principle on the primary
source of heat we know - the warmth of the sun. It warms you and the objects around you
instead of the air that you breathe.
The warmth felt from the suns rays is not
warm air but actually infra-red energy.
HOW DOES RADIANT HEAT WORK?
Like the sun, radiant heat moves in straight lines, warming all the objects in it´s path
which in turn act as small heat convertors, giving off their own gentle heat thus
preventing people losing warmth to cold objects such as walls, floors, tables, chairs,
The key aspect of radiant heat is its transmission by electromagnetic waves.
Air is transparent to the transfer of
energy, which occurs directly from warmer to cooler objects.
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ARE THE ADVANTAGES AND DIFFERENCES AGAINST OTHER FORMS OF HEATING?
The biggest difference between radiant heating and conventional heating systems (hot air)
is that, radiant heat controls the rate at which your body loses heat. Hot air systems
just put air into the room without heating the objects.
The air quality of your home is cleaner because dust and other air pollutants such as
mould, fungi, bacterium and viruses are not blown as with conventional "forced
air" systems. The absence of air vents also creates a quiet and peaceful atmosphere
in your home.
Radiant heaters are safer, more durable and more cost effective than all other forms of
During tests in the United States
carried out by the American Society of Heating, Refrigeration and Air Conditioning
Engineers (ASHRAE), a room was built containing every form of heating commercially
available. Test subjects invited to participate were exposed to the different types of
heating and asked to set their own comfort levels using thermostats marked only with
numbers and showing no temperature settings. The results showed that when exposed to
radiant heat, the test subjects selected temperature levels on average 5.6ºC lower than
any other form of heating.
Radiant heat is clean - fabrics and painted surfaces stay brighter and fresher because
radiant heat carries no grimy fumes and dust to soil them as with systems that heat the
air. Cold surfaces such as walls and floors attract grime and dust more readily than warm
Thermostatically controlled high consumption oil-filled
radiators (1200W-1500W) switch themselves off when the room reaches its desired
temperature. Most people budget that they will be on standby for approximately 50% of the
time, however, in general they run for at least 75% making them an expensive heating
Conventional heaters allow the heat to collect unevenly where it is most likely to escape
- the ceiling and along walls. Because the temperature with radiant heat in a room remains
relatively constant, heat loss can be reduced by up to 25%.
Rooms heated by fan heaters lose heat as soon as they are switched off because they only
heat the air, not the objects, which in turn heat the air.
The lower temperature required for a radiant heat
system helps to maintain natural humidity and lower static electricity levels.
Humidification is unnecessary with a radiant system because radiant heat does not alter
residential air moisture content, which is generally adequate if the air is not dried out
by combustion or by increased infiltration of cold, dry outside air.
No heat is as healthful and safe as
radiant heat, which produces no chemicals, dust particles, odours or fumes, thus making it
more appropriate for asthmatics, arthritis sufferers, persons with allergies or chemical
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HOW DOES RADIANT HEAT AFFECT US AND OUR BODY?
People actually accept radiant
heat better than any other form of heating which is why the principle is used in
incubators for keeping babies and chickens warm.
Your body has its own heating system which helps sustain life. Marvellous though it is,
the human heating system alone can't keep you comfortable. For while the body generates
heat, it also loses heat. Body heat is given off in winter by radiation, convection, and
in a minor way, evaporation.
Radiation is the transfer of heat by direct rays from your body to cooler objects
around you. Place your hand next to a block of ice and you'll feel a chill as rays of heat
leave your hand. Similarly, cold walls and floors draw heat from your body.
Convection is the transfer of heat from your body caused by the movement of air
around you. A fan cools you because the draft pulls heat from your body. Even warm air
will chill you if it moves rapidly around you.
Evaporation is the transfer of heat from your body caused by water drying on your
skin, as when you step from the bath.
This only plays a minor part in body's the heat loss.
Your body acts like a radiator - when you are not doing any work, your body produces about
400 BTU´s /hr. You give up about 100 BTU´s /hr by expiration (perspiration and
breathing). Another 200 BTU's are lost by radiating towards cooler objects around you.
The rate of heat
emission from the human body is influenced by the air temperature, the air velocity and
the mean radiant temperature to which the body is exposed. Low air temperature has the
effect of increasing body heat loss giving rise to the sensation of cold. Conversely, the
body feels warm when mean radiant temperature and air temperature are increased and the
air velocity is reduced. In terms of achieving comfortable warmth, experiments show that
increasing the mean radiant temperature has approximately twice the impact of raising the
This explains why radiant heat is so
effective in providing comfortable warmth. Therefore, your surroundings affect the rate at
which you give off body heat. If the body is properly balanced with the environment, you
feel comfortable. Several things influence this such as drafts, cold walls and floors,
losing as much as 50% of a bodies heat - a bare foot on a cold floor or an arm brushing
against a cold wall.
With radiant heat, surfaces are not
prone to loosing heat, so it is not necessary to overheat your home to maintain a
comfortable temperature. When the objects in a room are warm, the comfortable temperature
remains with a lower expenditure of energy. As the heat is distributed evenly throughout
the room - radiant heat provides true comfort.
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