There are significant disparities between the kinds of electric infrared heaters available; and major differences in their effectiveness and suitability in differing outdoor settings.
The principle of radiant heating is well-established, and there are important distinctions to be made between long wave and medium or short wave emitter quartz lamps.
Electric infrared energy travels in a straight line from the heat source, spreading out over distance, and is directed into specific directions by optical reflectors. For successful comfort heating, there must be reasonably even levels of heat throughout the area to be heated. Proper mounting heights of the individual heaters, accurate heater spacing, and heat wattage must all be considered to generate effective heating levels.
Short wave high intensity quartz heaters work like the sun and have a warming effect the instant the heaters are switched on. Short wave heaters warm people and objects in the beams range rather than the air; resulting in a pleasantly fresh warmth rather than stuffy warm air. Long and medium wave heat has comparatively poor heating characteristics, especially when used outdoors, as it relies on heating the air and does not penetrate to the skin to and warm up the person.
In addition as long and medium wave heat warms via the air, it is susceptible to air movement and therefore not easily and reliably directional.
In reality, a medium wave filament, which only heats up to around 900º Celsius, is more suitable for curing and drying processes rather than for outside heating applications, although cheap heaters with medium wave filaments can and are sold as exterior heaters! Long wave heaters are most suited to heating inside areas where a low level of heat is required and it is acceptable for the heaters to be in use for some time to pre-heat the area before it is occupied.
Short wave lamps
Short wave halogen heat lamps consist of a tungsten
filament heated by an electric current to a temperature of
some 2200º c. At this temperature most of the emission
(95%) is in the short wave infra-red band.
The moment short wave heaters are switched on, warmth is apparent, so the heaters only need to be switched on at the times an area is occupied.
For heating applications a red or gold coating encloses the halogen heat lamp to filter out the intense white light and provide a more aesthetically pleasing warm light.
What to look for
When selecting a patio heater, it is important to consider
the place in which they will be situated. As a rule, most
heaters should only be mounted horizontally, however,
there are a few that have been designed to work mounted
vertically.
A short wave outdoor heater should always have a highly reflective, long-lasting reflector which focuses its heating energy. A major benefit of being able to adjust the beams direction is that high intensity heating can be given at lower level even though the heater is mounted much higher.
Don't pay for features you don't
need
Some heaters are marketed with a high IP (ingress proof)
rating, for example, IP65. Before paying extra for it, ask
yourself, if it is really necessary for your application.
Many heaters are installed under some cover, like an
awning or parasol, which provides some protection. If so,
then IP24 is usually a sufficient rating for permanent
outdoor installation.
If a heater has an IP65 rating, check whether it can be re- lamped. In a heater with a wire guard, the wiring is normally such that the heater will either need to be stripped down by an electrical engineer for re-lamping or returned to the factory, which is both expensive and inconvenient as the heater will be out of service for some time.
Beware cheap Chinese copies of quartz patio heaters - the old adage "you get what you pay for" applies to most things in life including patio heaters. These heaters only use ordinary glass which does not allow heat to pass through and can shatter under the heat duress. The component parts give poor heat output and an inadequate lamp life of around 12 hours rather than 1,100 - 7,000 hours.
Consider ways to make cost savings
The running cost of most electric patio heaters is around
9p per kW hour, and there are several ways to ensure that
costs are kept low without compromising on heat for those
using the outside space. As we have seen, the efficient
nature of short wave heaters mean that they can be left
switched off when the area is not in use; as they work
instantly when heat is needed. Several control systems are
available that both enable heat output to be varied
between 30 per cent and 100 per cent, and also control,
the periods when the heater itself operates. These
controllers can stop the heater turning on when the
ambient air temperature is sufficiently high not to
warrant them. Some switches can ensure the heater only
comes on for a specified time period to avoid it being
left on when perhaps no one is present. There are also
options for PIR switches that detect movement and
automatically turn the heater on when people are in its
direct vicinity or combinations of the above to suit any
individual circumstances.
Increasingly creating a pleasant and comfortable area for smokers is a pressing need for many businesses wishing to avoid a downturn in profits as smoking bans hit home. Some careful research into the options available for heating will ensure that the heated outdoor area can help to improve profits, rather than becoming drain upon them.
Choosing the Best Electric Heater for your
needs
Ask your self:
How much heat do I actually need?
Do I need heat all year even when the outside temperature
is below freezing?
Where will I mount or stand the heater?
What power source is available
Does the heater need to weather/rain proof?
If buying a parasol fitting heater, how often will the
parasol need to be taken down?
Who controls the heater?
The customer? perhaps a timer switch is called for?
Me? Perhaps a controller is needed to adjust the
temperature?
If you know the answers to these questions, the heater(s) will usually choose themselves, however, we are always pleased to speak with our customers and make recommendations based upon your specific circumstances.
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