Horizon Energy Systems has been involved in
the design, testing, patenting and manufacturing of Radiant Barrier Systems
(RBS), since 1986. During this time there have been many products labeled
as a "radiant barrier" but most fall short of the true description of this
relatively new building product.
In the content below I will attempt
to explain what I've learned from decades of research and hundreds of hours
spent behind an infrared camera watching heat move.
Below
are terms describing the effects of radiation you may have never heard before,
the most important being "emissivity". Most home builders, architects and
engineers I've spoken with for the last 20 years have not been exposed to this
type of information despite years of university studies, myself included.
It was only through extensive research at libraries that I became aware how
easily infrared heat moves into and out of our homes.
Should you have any
questions after reading the information
below regarding how our patented products can help you lower rising energy costs
and make your home more comfortable, and why our products are superior to what
is available currently, drop me an email with your questions and I will attempt
to answer them.
Brad Lindsay, Horizon Energy
Systems
UNDERSTANDING HEAT
There are three methods heat
moves: Conduction, Convection and Radiation. While all three are
understood and recognized, it is my opinion only one method of heat flow needs
to be controlled: radiation. Conduction and convection are paths that heat can flow while infrared
radiation is a source of energy. All heat starts with radiation.
Control radiation and energy wasting convection and conduction are diminished as
well. Infrared radiation is an electromagnetic wave that travels
effortlessly through the air and changes
into convection and conduction once it strikes a surface.
Conduction
and convection are excited molecules creating friction which in turn allows heat
to move. Put a pan on the stove full of water, turn on the heat (gas or
electric), and the metal pan will conduct the heat from below into the water
through conduction.
Convection is the movement of a fluid (air is a fluid),
which is heated and moves due to changing the density. A Lava Lamp is a
great tool for watching the movement of convected heat. The less dense
bubbles of color, heated by the light below, travel upwards through the colder
(more dense), clear liquid to the top. Once it cools off and loses heat,
the density increases and it falls back to the bottom of the lamp to be heated
again. Looking closer we find the source
of heat is the radiation from the light element blasting infrared heat
from the bulb to the glass container at 186,000 miles per second (the speed of
light). Put a true RBS between the
element and the jar and there will be no "lava lamp effect" as there will be no
movement of heat. But what is a
"true RBS"?
To understand how a radiant barrier works we need to look
into the past where we can find the inventor, Sir James
Dewar. Dewar was a pioneer in liquefying gasses which required very
low temperatures, close to absolute zero (minus 359 degrees Fahrenheit).
Once liquefied, there was no method to store these super low temperature liquids
so Dewar invented what became known later as the "Dewar's Flask". This
flask was two glass spheres, one inside the other each coated with silver which
had a vacuum between the two surfaces to eliminate connective losses. The
Dewar's flask later was marketed as a product we all grew up with called the
Thermos Bottle. Ever look inside a Thermos bottle? It's very
reflective and very high performance and
can be very effective for keeping coffee hot or ice tea from getting warm.
In short, keeps heat from moving into or out through the shell.
Why
does it works so well? A Thermos bottle has two reflective surfaces facing
each other without contact. This
is a true radiant barrier. To fully understand why this works you
must first learn what emissivity is and how it affects our energy bills, our
comfort and our lives.
Imagine for a moment, a home completely
protected in a membrane that mimicks the performance of a Thermos bottle.
It would reqiure very little energy to stay comfortable during the hottest days
of summer or the coldest winter nights as heat would be reflected at the
building shell.
UNDERSTANDING EMISSIVITY
Let's let Webster
start with the definition:
Emissivity explained in layman's
terms
Webster's
definition: Main Entry:
emis·siv·i·ty
Pronunciation: "e-m-i si-v-i tee
Function: noun
Inflected Form(s): plural -ties
Date: 1880
: the relative power of a surface to emit heat by radiation : the ratio
of
the radiant energy emitted by a surface to that emitted by a
blackbody
at the same temperature
Ok, in layman's
terms: Emissivity is the ability for radiant heat to leave the surface of
an object. It matters not what the density, mass or thickness of the
object, only the surface. As can be seen below in Fig 1.2, emissivity (E
factor), plays a significant role in how heat moves into or out of our
homes, our cars, our bodies. The higher the number, the faster infrared
heat can emit from the surface. Pay close attention to the values of all
building materials.
Fig
1.2 EMISSIVITY OF
VARIOUS COMMON MATERIALS
Material
Emissivity value
Gold, polished .03
Metalized Film Radiant
Barrier .04
Silver, polished .04
Chrome .05
Aluminum, polished .04
oxidized .78
Brass, polished .04
oxidized .61
Iron, polished .21
oxidized .69
Copper, polished .05
oxidized .78
Human skin .98
EMISSIVITY OF
BUILDING MATERIALS
Wood .95
Glass .94
Paint, average of 16
colors .94
Brick, common red .93
Concrete .92
Plaster, rough coat
.91
Source: Handbook of
ChemistryIf you are still reading, let's examine how a radiant
barrier should be manufactured.
Start with the most reflective surface you can find, then face it towards
another reflective surface without touching the other one. Herin lies the
trick and also what has taken me decades to overcome the design
considerations.
There are many companies claiming to have a radiant barrier
but fall short of this description. As soon as the reflective surface is
laminated to another surface, be it bubble pack, foam, plywood, cardboard or a
flexible membrane, you lose all the emissivity properties that allow a RBS to
work. There must be at least two low emissivity surfaces facing each with
as little contact as possible to be considered a true radiant barrier
system.
All of our products have this feature designed into them for
this purpose. High performance, lower energy costs and more comfort.
If you understand the content above you will be on your way to
purchasing the most efficient RBS available anywhere at any price available here
at Horizon Energy Systems. Should you have any questions regarding the
content above, please feel free to send us an email with your questions and we
will attempt to address them as soon as possible. The only thing worse
than buying the wrong product is putting into your home or addition and finding
out later it was not done correctly and cannot be removed. Do it right the
first time and let us help you choose the right product for your
application.

If your new home or addition does not
look like this before the exterior is installed, you will be paying too much for
energy and comfort....forever.
Do it right the first time. Click on
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more.
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