Welcome to Sigma Radiant Barrier Technology

At BRT, we specialize in providing top quality, effective, affordable solutions for insulating your home, business, or agricultural buildings.

The most cost-efficient path to raise the energy efficiency level of any household or building is to improve its insulation. A better-insulated house will cost less to heat in the winter and less to cool in the summer, thereby saving you money all year-round.

One of the top ways we have found to cost-effectively improve the insulation value of any building is through the installation of Sigma’s ThermFlux 3100 Series radiant barrier technology. We are right now the main distributor and installer of Sigma’s ThermFlux 3100 Series radiant barrier. We have installed hundreds of thousands of square feet in a variety of different buildings over the past few years. The results when installed correctly have been astonishing. Below is some more information about Sigma radiant barrier. And some of the benefits it offers.

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Sigma - Radiant Barriers

Sigma Labs produces a series of radiant barrier products specifically designed to block radiant heat energy from entering, or leaving any building. Unlike conventional radiant barriers that require reflective films to be laminated to a reinforcing scrim, Sigma radiant barriers include single-layer fabric to which the reflective surfaces are directly deposited. The resulting product has a higher strength and greater resistance to corrosion.


Why Radiant Barrier?

“Traditional” insulation yields traditional results. Furnaces and air conditioners run constantly, energy bills are high, and discomfort in a home is accepted as being normal. Insulation systems can be designed to make a structure more comfortable and efficient – virtually eliminating cold corners, hot second-stories, and discomfort near exterior walls. It’s all due to the aluminum component of radiant barrier! Aluminum is most effective when combined with an air-space and stops 95% of radiant heat loss when there’s an air-space between the heat source and the aluminum. Air-seal this assembly and total heat loss approaches zero! The result is a thermos bottle form of insulation system.


Radiant barrier technology has a long list of benefits when installed and used correctly – in houses, shops, livestock barns, essentially any building envelope. These benefits include:

    • A cooler building in summer, and warmer in the winter.

    • A more stable inside temperature and environment, diminishing cold or hot corners in a building or barn.

    • Lower heating and cooling costs

    • For livestock, it can help decrease Black Globe Effect - See below

    • Helps create a more stable structural environment, decreasing expansion/contraction cycles that gradually weaken and destroy a building envelope.


How Heat Works in Structures

Heat is transferred in a building in three ways: radiation, convection, and conduction.

CONDUCTION is direct heat flow through matter via molecular motion. It results from actual physical contact of one body with another. For example, a cooking pot on a warm stove receives its heat via conduction. In a wall, heat conducts through objects in direct contact with each other. Heat conducts through studs, drywall, and yes, insulation installed without an air-space. Heat is always conducted from warm to cold, and always moves via the shortest and easiest path.

In general, the denser a substance, the better conductor it is. Solid rock, glass and aluminum are very dense and therefore are good conductors of heat. Reduce their density by mixing air into the mass, and their conductivity is reduced.

The percentage of heat transferred by conduction through the air is comparatively small. Two thin sheets of aluminum foil with an inch of air space between weigh less than one ounce per square foot. The ratio is approximately 1 of mass to 100 of air - most important in reducing heat flow by conduction. The less dense the mass, the less heat will be conducted!

CONVECTION is the transport of heat within a gas or liquid, caused by the actual flow of the material itself (mass motion). In building spaces, natural convection heat flow is largely upward, somewhat sideways, but not downward. This is called "free convection."

For instance, a warm stove, person, floor, wall, etc., loses heat by conduction to the colder air in contact with it. This added heat activates (the warms) the molecules of the air, which expand, becoming less dense, and rise. Cooler, heavier air rushes in from the side and below to replace it. The popular expression "hot air rises" is exemplified by smoke rising from a chimney or a fire. The motion is turbulently upward, with a component of sideways motion. Convection may also be mechanically induced, as by a fan. This is called "forced convection."

RADIATION is the transmission of electromagnetic rays through space. Radiation, like radio waves, is invisible. All materials emit infrared radiation (IR) if they have a temperature above absolute zero (-459.7 F). This includes the obvious sources like the sun or a radiator, but also icebergs, humans, animals, furniture, ceilings, walls, floors, etc. Read more about IR in the links below.

Being all objects radiate infrared rays from their surface in all directions, in a straight line, until they are reflected or absorbed by another object. Traveling at the speed of light, these rays are invisible, and they have NO TEMPERATURE, only ENERGY. When an object is heated, its surface molecules are excited, causing them to give off infrared radiation. When these infrared rays strike the surface of another object, the rays are absorbed and only then is heat produced in the object. This heat spreads throughout the mass by conduction. The heated object, then transmits infrared rays from exposed surfaces by radiation to other objects.

The amount of radiation emitted is a function of the EMISSIVITY factor of the source's surface. Emissivity is the rate at which radiation is given off (EMISSION). Therefore, when infrared radiation strikes an object, some of the energy is reflected (bounces back) and some is absorbed. Some of the absorbed energy is then emitted away as more radiation.

Here’s an example. Take four iron radiators and heat them to the same temperature. Wrap one with aluminum foil (extremely low emissivity), paint one with aluminum (low emissivity), one with ordinary enamel (more emissive), the fourth covered with asbestos (highly emissive). The radiator wrapped in aluminum foil will emit, or give off, a mere 3% of its radiation. The enamel and asbestos will give off a considerable amount of radiation (even more than the original iron!)

Materials whose surfaces do not appreciably reflect infrared rays, i.e.: sheetrock, wood, glass and rock, have absorption and emissivity rates ranging from 80% to 93% - meaning that they easily give away their radiant energy. Most materials used in building construction -- brick, stone, wood, paper, and so on -- regardless of their color, absorb infrared radiation at about 90%. It is interesting to note that a mirror of glass is an excellent reflector of light but a very poor reflector of infrared radiation. Mirrors have about the same reflectivity for infrared as a heavy coating of black paint.

The surface of aluminum has the ability NOT TO ABSORB, but TO REFLECT 97% of the infrared rays which strike it. Since aluminum foil has such a low mass to air ratio, very little conduction can take place, particularly when only 3% of the rays are absorbed.

TRY THIS EXPERIMENT: Hold a sample of FOIL INSULATION close to your face, without touching it. Soon you will feel the warmth of your own infrared rays bounding back from the SURFACE. The explanation: the emissivity of heat radiation on the surface of your face is 99% - the absorption of aluminum is only 3%. It sends back 97% of the rays. The absorption rate of your face is 99%. The net result is that you feel the warmth of your face reflected.

For more info on radiant barriers and radiant heat please visit the links below:

More on why Sigma is one of the best radiant barriers to use


When a high reflectivity, low emissive material like Sigma's ThermFlux 3100 Series is facing into an open and vented space like an attic, it is called a radiant barrier.

A radiant barrier works by reflecting 95% of the infrared or radiant heat that strikes it, and by not emitting over 5% of infrared or radiant heat through it. By preventing radiant heat from entering or escaping, a radiant barrier reduces the energy spent on heating and cooling and can make the home significantly more comfortable year around.

Stronger, Lighter, & More Durable

At a fraction of the thickness and weight, the ThermFlux 3100 Series is over twice as tear-resistant as the competition when tested to ASTM D4533. This means it will continue to hold nails and staples under pressure. Up to 50% lighter and thinner than competing radiant barrier products, ThermFlux 3100 Series rolls make storage, transportation, and installation easier. What’s more, ThermFlux 3100 Series products do not have to sacrifice any strength or durability to do so.   

Faster, Easier Installation

Sigma’s ThermFlux 3100 Series radiant barrier installs easily, with both lightweight and excellent tear-resistance that make remodeling work a breeze. Never before has a radiant barrier or reflective insulation been so strong while still so thin and lightweight. The weight makes it possible to bring up entire rolls at once, and the durability ensures worry-free installation with staples or nails, making ThermFlux 3100 Series radiant barrier a key component of any contractor or energy auditor’s portfolio. 

Sigma’s ThermFlux 3100 Series Testing

Every single roll of the ThermFlux 3100 Series radiant barrier is tested for emissivity and reflectivity, and corrosion and aging prior to your shipment. The product comes with high reflective metallization on both sides and frequent perforations for breathability, but the product can be manufactured with the metallization on one or both sides, and with or without perforations, depending on your specific needs. ThermFlux 3100 Series radiant barrier conforms to the following specifications:

• 95% Reflective and 5% Emissive when tested to ASTM C1371

• No Delamination or Bleeding when tested to ASTM C1313

• No Loss of Reflective Surface when tested to ASTM D3310

• No Growth of Fungi or Mildew when tested to ASTM C1338

• 6.9 Perms of Water Vapor Transmission when tested to ASTM E96

• 0 Flame Spread and 10 Smoke when tested to ASTM E84 with ASTM E2599

• 0 Flame Spread and 7 Smoke Developed Classification when tested to CAN/ULC S102.2-10 (For Canada)

• 46.8 MD and 27.4 CD Trapezoidal Tear Strength when tested to ASTM D4533