Infra-Red Heaters
This style of heater works on the principal of infra-red radiation just like
the sun only without the ultra-violet radiation, so you won't get a sun tan
from working under one of these heaters. This style of heater uses a 4"
diameter tube with a reflector over the tube much the same as florescent
lighting. There is a gas burner at one end and an exhaust termination at the
opposite end of the tube. Tube heaters can range in length from 10 feet to
70 feet and BTU ratings from 40,000 to 200,000 BTU's. At my last count there
were about 12 different manufacturers fabricating their own version of the
product which is testament to the popularity of this form of heating. There
are two basic types of infra-red heaters. One uses an open flame visible
from floor level and concentrates a large amount of heat in a small area.
This unit is a "High Intensity" infra-red heater and does not have a
chimney. The products of combustion from this style vent into the work space
and are exhausted by a wall or roof fan that is interconnected to the
heaters. The open flame of this style limits the applications and is
therefore not as popular as the other style, referred to as a tube heaters.
Tube heaters can be used almost in any application including requirements
for closed flame or "sealed combustion" such as woodshops or spaces where
volatile or combustible liquids are used or stored. This is a popular
choice for landlords as it permits a wider range of possible tenants.
Infra-red heat, heats objects, not air and therefore the opening of a
shipping door does not cost you all the heat that is lost with a suspended
unit heater. All the heat with tube heaters is concentrated in the floor
slab, inventory stored in the area and / or the machinery at floor level and
not up at the ceiling like with suspended unit heaters. The efficiency is
higher with this style of heater and savings from 33% to as much as 50% can
be realized over suspended heaters. Combustion air can be ducted directly to
the burner from outdoors (required in sealed combustion applications) which
means there is no wasted energy from chimneys and no change in the building
pressure. Because this system operates like the sun, if you are outside of
the area focused by the reflector it is like stepping into the shade
outdoors. This fact means you can heat a tiny little area of a large
warehouse to 70 degrees and have the rest of the area at freezing
temperatures. In fact you can have many areas under the same common roof at
different temperatures. You could not achieve this with suspended unit
heaters that heat only the air as the heated air will migrate to the colder
zones. This fact alone is why the savings are so great with tube heaters. A
typical tube heater will use a motor rated for about 1/15th horsepower to
propel the gas flame through the tube versus a motor rated for 1/3 to 1/2
horsepower for a unit heater. This saves a considerable amount of hydro
costs. There is no air movement with tube heaters as there is no fan to blow
the heat around like with unit heaters so dust control and air quality
becomes easier. Tube heaters do not have to be installed in a straight line
for the entire length of the heater. Once past the first 20 feet the tube
can be turned 90 degrees or 180 degrees to concentrate more heat in one area
such as a shipping bay. The exhaust can be terminated through the roof or a
nearby sidewall. Tube heaters generate a fraction of the noise of unit
heaters and are virtually maintenance free by comparison. The reflectors on
tube heaters can be angled to increase the base area of coverage and are
even used in arenas to keep spectators comfortable right at ice level. We
have customers that cure manufactured concrete wall sections with infra-red
heaters. Like sunlight, darker objects in the path of the light rays will
absorb more heat than a lighter object, so floor coloring is important. The
best example of this is a black car and a white car parked beside each other
on a sunny day. The black car will get hotter and absorb more energy. The
following is a recap of the benefits and features of tube heaters.
- Higher efficiency, over 90% and fuel savings up to 50%
- No air movement therefore reduced circulation of dust and odors
- Reduced hydro costs to operate versus unit heaters
- Greater ceiling clearance versus unit heaters
- Sealed combustion for more applications in rental spaces
- No change in building pressure
- Reduced noise levels
- Able to heat a small area versus an entire warehouse
- Heat is retained in objects and floor not the air that reduces
recovery time when overhead doors are opened
- Payback in fuel savings over unit heaters
- Reduced heat stratification, heat is at the floor not the ceiling
- Virtually maintenance free
- Will qualify for energy rebate from the gas company
Drawback... yes there is one. The up front installation cost is about 25%
more in new construction and about 35% more in a retrofit when changing from
unit heater to tube heater. Most of this cost is in adding a second roof
opening for the exhaust or combustion air and rental cost of a scissor lift
for the installation. It is this writers recommendation that infra-red tube
heaters are the way to go for comfort, efficiency and long term economy.
